Tips for working with plexi/acrylic

[Cannibal23]

Common terms
- Plexiglass, Perspex, plex, plexi, acrylic, all refer to the same chemical compound (Polymethyl methacrylate - PMMA). wich hence forth in this document shall be refered to as plex or plexi. Another compound known as lexan has a simaler appearance to plex however may handle diffrently. this document is intended for use with PMMA based products only.


Please note these tips are a in my own words summery version from what i understand of what was said all over the net. A link will be at the bottom to some conversation about this

*******Cutting*********

i have heard success using the folowing :

Drimel - use the cutting wheel. typicaly you hear that you should use a low rpm to cut as a high rpm has more of a tendancy to melt (so they say). i have recently heard otherwise so if you have some scraps test out whatever way you prefer to see what suits you best. Drawbacks of using the drimel is that the cutting wheel on this device works like a very fine grind stone and thusly cuts by friction resulting in the plex getting very hot and melting a little so cut a little wide of your lines. also due to this abbrasion meathod the edges of your cut will be not very clear. very scratched up and a pain to polish.

jig saw - I have never used one for this but from what i hear you need to use a fine tooth hacksaw blade. the edges left over will likely be alot less rough then with the drimmel. from what i can tell with this cutting meathod you could potentially chip the surface of your peice when the blade retracts. so make sure its a sharp blade. beyond that you should be carefull of the vibration here as if your blade binds up it could cause cracking.

score and break - This meathod is exatly what it sounds like. you make a cut on the surface of the plex i would say 1/4 of the way through should be enough to make sure it stays on the lines you want. then put one side of the plex on something like a table and press on the side that remains hanging over to flex that cut open. doing this in a sharp and abrupt mannor should cause the plex to snap roughly allong the lines you have cut into it. this leaves a more clear edge (except for the little bit you cut).

hack saw - yes the tried and true old school meathod. works ok but if you have alot of curvs ... well lets just say its time consumeing. again make sure your blade is very sharp. has about the same finish as with the jig saw meathod.

scroll saw - like a band saw, except the blade isn't continuous. This allows you to do piercing work - like a custom fan grill. The blades can be incredibly thin.


**********Cleaning ,polishing, scratch removal**********

Cleaning - Plex has a very soft surface as it is just plastic. Unfortunately this lends itself to scratching easly. it is best to wash and then wipe if there is some dirt on it. rather then just wipe. DO NOT use alcohol based cleaners. i have heard that this can make the plex crack. personaly i just use soap and water with a very soft cloth. try to use a clean cloth to wipe it down with. if you use a dirty one you may find soemthing stuck to it may scratch the surface of your plex.

Scratch removal - lets say you do manage to scratch the surface area of your peice. dont dispare. you might could recover. apparently there is some products for plex that you can use to remove scratches and polish it back to being clear. They have diffrent numbers associated with them depending on what they do. Try using Novus #2 (scratch remover) then polish with novus #1(...polish..) for a perfect finish.

Novus#2(RED) is the scratch remover
Novus#1(blue) is the polish
check it out
http://www.tapplastics.com/shop/product.php?pid=113&


Polishing - Again you can use the same compounds as you did in the previous section. it also works on the edge peices too after some sanding. you need to use a very high grit sand paper to flatten out and smooth the edges over. i hear once you think your done with the sand paper that you can use toothpaste to give it an even nicer finish. or instead you can use the stuff from the previous section Novus #2 then polish with novus #1. There is another method to polish the edges. this is called flame polishing. this can be tricky so i strongly suggest trying it on scraps till you get the hang of it. essentually what it entails is using the heat from a flame (not the acctuall flame itself) to soften and melt the flat part of the edge and allow it to melt down into the scratches you made while cutting out your work. best tools for this seem to be propane torches butane torches, or any other device that does not have a yellow / orange flame (leaves icky carbon on your work). you want this flame to be controled so propane torch / butain torch is perfect. WARNING! do not use flame polishing on edges that you wish to join to something else. The melting process typicaly mildly deforms the edge so it is not flat anymore makeing it more diffuclt to glue and get a good seal.



********* Glueing and afixing your plex**********

Fixing to other plastics - if you are trying to stick some plex togeather to create a complex shape you will need something to glue it togeather properly. forget crazy glue guys. here is what you want to use. IPS Weld ON #4. there is also an IPS Weld ON #3 and it is fast drying. probably best to take the longer drying kind though. most likely it does a better job.
http://www.tapplastics.com/shop/product.php?pid=131&

fixing to wood - dont know whats the best for this if i find it iw will edit this document

fixing to metal - i have experimented with epoxy and it seemed to work ok to a particular extent. the problem seemed to be when the steel flex. plex is more rigid then the lite steel used on case sideings and thusly seems to break the bond to the steel when and if the steel tries to flex. perhaps the gauge of plex i used was too thick. i think it was 1/8 inch. anyways if you do decide to glue to steal its a good idea to sand the steal with rough sand paper as well as the area of plex that will acctually be glued. this allows the glue to get a better grip on both peices. again if you know something i dont ( and you most likely do ) please share with us and i will add it to this document.

Rivoting - if you need to rivot plex to lets say steel it is better if you can use aluminum rivots. they tend to not take as much pressure to crimp and snap the end off as steel rivots. this should prevent your work peice from cracking while you apply nessasary force to pop your pop rivots. also please remember that it is a good idea to not put rivots in on the very edge of your peice. good practice is to leave a healthy area between the edge of your plex and the hole you make to rivot. for example
if this is how thick your plex is | | then you should leave about this much space | | before putting a hole to rivot. this should ensure that you dont ruin your work at its last stages and have to start all over.

Bolts - lots and lots of diffrent shapes types and sizes here folks. find one that suits the look your trying to get best. Concider countersinking your holes so that the bolt heads dont stick out. the Benifit of bolting rather then glueing or rivoting is that your plex can be removed and washed if required. i supposed you could remove the other types mentioned here but it would only create alot more work for you (have fun drilling out those rivots and not scratching your plex). one remaining thing to say is that if the excess threads on the bold stick out alot you may want to concider marking them, removeing the bolt and cutting off the extra.


********Shapeing********

preform shapes - if you heat plex up it will become plyable enough to mold it onto diffrent shapes. probably the esiest way of doing this is with the element of your electric stove at home or other simaler device(space heater maybe?, basebord heater? heat gun? my fingers after typeing this much?). essentually try to keep the parts you want to bend warm to the point that they can bend fairly freely. i tried this for the first time last night so i am not an authority on it but it seems fairly easy. i heated up the plex by holding it over the element (not touching) untill it was somewhere between rigid and playdoh. keeping it at this state allows you to form your shapes without haveing to worry about the plastic drooping too much or getting bubbles in it. by heating it, while bending it should prevent little stress cracks that later could show up as little white lines. once its warm enough you can use other objects to help you mold the shape you want. be ware of heavly textured surfaces as i think that could imprint a pattern on the surface of your plex if its hot enough. Finaly, once you have accieved the desired shape you can dunk(if its small enough) your work in cool water to harden the plex again.

this about sums it up for now. i will likely be updateing this with any new info or experiances i come accross. if you see something that is in correct or have another / better way of doing something you see here feel free to comment. if you have a tip or a trick please try to make an obvious heading at the top of your post denoteing what it has to do with for example

****** glueing******

this way people can more quickly find the things that pertain to them.

thank you for your time


here is the link to the thread i found
http://www.twistedforums.com/forums/archive/index.php/t-1354.html

[Cevinzol]

Nice article.
You might want to add that Plexiglass and Perspex are the same thing (Polymethyl methacrylate - PMMA). Perspex is the UK trade name for it. Also Lexan is similar but I believe it handles differently. Anyone more knowlegable should comment on working with lexan.

scroll saw - i dont know what this is but i keep hearing people use it. will edit this entry to include any info someone wants to add
A scroll saw is like a powered copping saw or jewlers saw. the blade is attached to an armiture at both the top and bottom and the motor does the sawing for you - like a band saw, except the blade isn't continuous. This allows you to do piercing work - like a custom fan grill. The blades can be incredibly thin.

[DaveW]

Very nice article. You could put something in about using a hot glue gun when attaching Perspex to metal, some people find that if you epoxy first then get the edges with the glue gun it helps to hold the thing together. It won't look reat though.


Thinking about expanding this for etchings as well? Good work so far though mate.

-Dave

[Cannibal23]

A scroll saw is like a powered copping saw or jewlers saw. the blade is attached to an armiture at both the top and bottom and the motor does the sawing for you - like a band saw, except the blade isn't continuous. This allows you to do piercing work - like a custom fan grill. The blades can be incredibly thin.

this sounds like an ideal tool. would allow you to cut out some very interesting shapes. any experiance using this tool? if so does it bind up alot? what blades do you use. how does it leave the edges. does it chip the surface at all. anything we should know about it like speed settings or things it dosent seem to do well with?

[Rankenphile]

Great tips.

[Cannibal23]

*****Drilling

if possable use a drill press. it does a much more accurite job. the hole will pretty well always be perfectly strait and perpenddicular to your work peice. it gives you more control then an electric drill or a drimel. it seems to be a good idea to drill pilot holes and then enlarge them with a bigger drill bit afterwords. i have heard this can help prevent cracking.


*****Etching

I use a Dremel with the 1/32 adn 1/16 engraving tips. Some people also use sandpaper. I keep the dremel at a fairly low speed(either the lowest or second to lowest) I find the faster it moves the worse your mistakes are. IE when you make a mistake at highspeeds, it usually makes a big gouge in the etch. I like to just let the dremel rest in my hand, so I am not putting ANY weight down on it. Then I just wave it back and forth across the etch at a fast speed(or at least start slow then work your way faster until you get used to the tool)

[Cannibal23]

i figured it would be a good idea to start pileing info up in organized places rather then have to go on safari every time i wanted to know something. just figured that while i was doing that i might as well make it easy for everyone else too.

[Malatory]

this sounds like an ideal tool. would allow you to cut out some very interesting shapes. any experiance using this tool? if so does it bind up alot? what blades do you use. how does it leave the edges. does it chip the surface at all. anything we should know about it like speed settings or things it dosent seem to do well with?

Blades are small metal blades 14-20 teeth per inch.

this is what a scroll saw looks like.

http://www.malatorymods.com/workshop/scrollsaw.jpg

and

http://www.malatorymods.com/workshop/scrollsaw2.jpg

the Edge depends on the blade. More teeth less sanding.

[qoou]

its a great tutorial but i have to point out that its wrong, there different types of plexiglass with different properties.

acrylic - an all around type of plexiglass, comes in most colors but not uv reactive.

lexan - more resistant to scratching, not as many colors, expensive.

PVC - Scratch and Crack Resistant, probably the most scratch resistant of all plexiglass. comes in various colors.

Copolyester - comes in only in clear, has the highest impact strength.

polycarbonate - probably the worst form of plexiglass. scratches easily, but comes in all sorts of colors, cheap.

[DaveW]

its a great tutorial but i have to point out that its wrong

Actually, he's not wrong. If you re-read it, it says:


Plexiglass, Perspex, plex, plexi, acrylic, all refer to the same chemical compound (Polymethyl methacrylate - PMMA). wich hence forth in this document shall be refered to as plex or plexi. Another compound known as lexan has a simaler appearance to plex however may handle diffrently. this document is intended for use with PMMA based products only.

Which is entirely true. Although what you've said is also right, and the information you've provided is helpful, you're not making many friends with your attitude.

Cannibal, don't be discouraged. This guide is damn useful, and i'll fill in any blanks where and when i can, as i'm sure the rest of guys will-and i'm sure thats what qoou meant as well. :)

-Dave

[qoou]

hey i thought the tutorial was great, i just had to point out that he was wrong in one part. no need to fight or get discouraged.

[OvRiDe]

Qoou,
I must a agree with Dave.. what Cannibal said was not incorrect, nor do I think what you said was completely incorrect, except for the point where you said Cannibal was wrong, and about polycabonate.
In his opening statement he spelled it out that he was talking about PMMA based products, where as you were quoting facts about 4 other completely different compounds. And of course they would have different characteristics then PMMA based products. BTW Plexiglas, Perspex, Acrylic are name brands for Polymethyl methacrylate.


Polymethyl methacrylate (PMMA) or poly(methyl 2-methylpropanoate) is the synthetic polymer of methyl methacrylate. This thermoplastic and transparent plastic is sold by the tradenames Plexiglas, Perspex, Acrylite, Acrylplast, and Lucite and is commonly called acrylic glass or simply acrylic. The material was developed in 1928 in various laboratories and was brought to market in 1933 by the German Company Röhm (GmbH & Co. KG).
You can read more about it here.. http://en.wikipedia.org/wiki/Polymethyl_methacrylate

LEXAN® is a registered trademark for General Electric Company's brand of highly-durable polycarbonate resin thermoplastic intended to replace glass where strength justifies its cost.
More info can be read here.. http://en.wikipedia.org/wiki/Lexan

Polyvinyl chloride, commonly abbreviated PVC, is a widely-used plastic.
Again you can read more about it here..http://en.wikipedia.org/wiki/Polyvinyl_chloride

A transparent copolyester with very high impact resistance, Spectar® sheet is the brand name for extruded Polyethleneterephtalate Glycol (PETG) copolyester sheet.
And yet again.. Bayplastics (http://www.bayplastics.co.uk/Product%20Materials/prod-barlo-spectre.htm) and Eastman (http://www.eastman.com/Brands/Spectar/)

Polycarbonates are a particular group of thermoplastics. They are easily worked, molded, and thermoformed; as such, these plastics are very widely used in modern manufacturing. They are called polycarbonates because they are polymers having functional groups linked together by carbonate groups (-O-CO-O-) in a long molecular chain. The characteristics of polycarbonate are quite like those of polymethyl methacrylate (PMMA; acrylic), but polycarbonate is stronger and more expensive.
They make eyeglass lenses out of polycarbonate because they are stronger, lighter then glass lenses, and they are more scratch resistant then plastic lenses. And from experience.. polycarbonate lenses are more expensive then plastic or glass lenses as well. Which is why along with the information above, I would say that your evaluation of polycarbonate isn't completely accurate.
And of course you can read more about polycarbonate here.. http://en.wikipedia.org/wiki/Polycarbonate

So keep in mind before you say someone is wrong, it would be a good idea to make sure that you are talking about the same thing, and that you have all your facts straight.

[DaveW]

Wow Overide, when you beat em' back, you beat em' back good.

-Dave

[qoou]

you're not making many friends with your attitude.


i don't that can help make cannibal's thread better...

Anyways...

maybe i should said that he could use more info, he said earlier that all the plastics could be treated the same(besides the lexan). they cant.



Plexiglass comes in many different names, colors, and thicknesses. The types are very important as some are more flexible, scratch resistant or heat retardant.


i just didnt know constructive crititsizm was a sin these days.

[OvRiDe]

i just didnt know constructive crititsizm was a sin these days.

It's not .. but saying some one is wrong, is not constructive. There are better ways to go about it, rather then just saying they're wrong.

[DaveW]

Hey qoou, i'm not trying to put you down bud. I did say that the info you provided was helpful, i'm just saying that telling someone they're wrong isn't constructive criticism. Don't take it personally, i know you meant well - but not everyone else does. It's not in what you're saying, just in how you say. I don't think you've really offended anyone, i'm just pointing out that some day someone might take your form of criticism as an insult.

Worry not, you posted back, stuck up for yourself, everyone's happy again.

-Dave

[qoou]

i didnt want to offend any one i just wanted to help out.

Cannibal... i apologize.

[XcOM]

it takes a dumb man to run away,

It takes a wise man to stand up, admit he's wrong and apologise!

[Cannibal23]

i didnt want to offend any one i just wanted to help out.

Cannibal... i apologize.

not concerned about it at all dude. no worries. this is all for the greater good to get this NFO out there and have people use these experiances to help them expand their creativity. the information you and overide have provided im sure will be a usefull gem to someone in the future. btw do you have any lexan if so can you fool arround with the scraps from an old project and post some info on how it behaves? i think that would be a great way to partisipate here

[qoou]

actually as a matter of fact i do have scrap lexan i can fool around with. i bought some at home depot the other day just for that purpose.

[Cannibal23]

actually as a matter of fact i do have scrap lexan i can fool around with. i bought some at home depot the other day just for that purpose.


awesome. perhaps you can try cutting it with diffrent tools and post the results on what left a better edge what tool you used how to clean up the edges. something on bending it would be kool too. would sort of fit this thred. hope its not too small. dont burn yourself in the process ok dude. safety first.

[qoou]

i just got a new carbide cutter for my dremel that ive been dieing to try out.

[tybrenis]

awesome. perhaps you can try cutting it with diffrent tools and post the results on what left a better edge what tool you used how to clean up the edges. something on bending it would be kool too. would sort of fit this thred. hope its not too small. dont burn yourself in the process ok dude. safety first.

http://www.thebestcasescenario.com/forum/showthread.php?t=2145&page=2

My work log shows a bit of cutting, bending, and flame polishing (watch the video). A guide is coming to my site, www.powerpackedpc.com, very shortly. I have a lot of professional acrylics experience so if you have any questions I can help you with that, I can be your insider, lol.

[qoou]

sweet!

[jdbnsn]

This is a great tutorial everyone, learned alot from reading it. I did my first experimenting with plexi this weekend and I just sort of walked in blind, I wasn't aware of this tutorial yet. Anyway, I found it was quite easy to work with and has limitless possibilities. I thought I would share with you how I cut mine and also raise some questions I have. First off, I forget what names you were using for which tools ( I am sure you are using the correct terms, I just get mixed up) but I use what I call a jig-saw (the one with the thin, reciprocating blade which was pictured earlier) for cutting many wood types. I use the scroll saw (hand held version of a jig-saw-is my terminology correct?) also for many woods. But for plex, I preferred the band saw for open edge cuts (we have a metal cutting blade on, an old one that doesn't matter if it gets ruined so I can cut anything with it), but found for enclosed circular cuts especially small ones, the coping saw was perfect. It's a little old school and if you haven't seen one, this is what it looks like:

http://i51.photobucket.com/albums/f395/jdbnsn/misc/coping.jpg

The blade is about half as thick as a hack saw and the depth is usually quite shallow (my blade is maybe 2mm tops). I used it to cut I/O ports on a custom plate for the rear panel of my media center by drilling small holes and you detach the blade at one end, feed it through the hole and re-attach then you're ready to go. If doing fine, close, tiny cuts and are not comfortable using a dremel for fear of over cutting I would say this is a great option. Here is my plate:

http://i51.photobucket.com/albums/f395/jdbnsn/wooden%20mc/IOshield.jpg

For fine tuning even beyond the coping saw, I just used typical metal files:

http://i51.photobucket.com/albums/f395/jdbnsn/misc/files.jpg

Now for some questions to the plexi-pros:

I wanted to know first off, if I only have clear plexi but wanted to tint it, is there an easy way of doing this? My only thoughts were colored magic marker (not likely to look spectacular), some type of thin paint, window tinting (limited colors range and I hear it doesn't stick), or glueing on a colored transparency. Any ideas on how I could do this without buying colored plexi?
Also, if you are etching on plexi and lets say drawing a letter in a word, do your grooves need to be square with the surface to look right? Or can the be concave with the surface and still look ok?
Lastly, where can you buy large sheets of it? I think i looked at lowes and Home Depot and neither had it, I had to get some from tybrennis online. But if I needed a large sheet, the shipping would be way too much?
Thanks a bunch all!

[tybrenis]

I wanted to know first off, if I only have clear plexi but wanted to tint it, is there an easy way of doing this? My only thoughts were colored magic marker (not likely to look spectacular), some type of thin paint, window tinting (limited colors range and I hear it doesn't stick), or glueing on a colored transparency. Any ideas on how I could do this without buying colored plexi?
Also, if you are etching on plexi and lets say drawing a letter in a word, do your grooves need to be square with the surface to look right? Or can the be concave with the surface and still look ok?
Lastly, where can you buy large sheets of it? I think i looked at lowes and Home Depot and neither had it, I had to get some from tybrennis online. But if I needed a large sheet, the shipping would be way too much?
Thanks a bunch all!

Hey,

Magic marker will leave marker lines and look like crap. Paint is very hard to get to stick to acrylic, especially if you can't rough up the surface, since you are trying to mantain transparency. I have heard of people using window tinting, but this is not very efficient, you are limited to only what you can fit into your kitchen pot, and is hard to come by (or atleast is for me). If you are just making a case window or something, you could use a tinted film and glue it beyond the window, so the glue isn't visible.

Honestly, the easiest and probably cheapest way to get colored plexi is to just buy it as such. Here are some good suppliers I have had success with in the past:

http://www.tapplastics.com/

http://www.mcmaster.com/

http://www.delviesplastics.com/

I don't know how big of a sheet you want, but if it is too big to be UPSed, it will have to go freight, which is pricey unless buying in bulk. I personally recomend going to google maps and trying to find some plastics suppliers in your area, sign shops and fabricators usually will give away scraps or sell them very cheaply, become a regular there and they will gladly cut all your acrylic or give you some scraps.

www.maps.google.com

Type in "plastics your-city-here" or something of the sort.

Good luck.

[jdbnsn]

That's a great idea, thanks again Tybrenis!
Jon

[tybrenis]

Glad I could help.

[Aero]

Or you can do it the TribalOverkill (look at the first few pages of Blackout) way and go to an autoparts dealer and get some adhesive window tint. Its a film that you apply and then sticks to the window. Its the same thing I'm using for my mod and hopefully will work :D

[jdbnsn]

Or you can do it the TribalOverkill (look at the first few pages of Blackout) way and go to an autoparts dealer and get some adhesive window tint. Its a film that you apply and then sticks to the window. Its the same thing I'm using for my mod and hopefully will work :D

We had discussed this earlier and there is some question as to how well it sticks. Please let me know how it works for you because if it works good, I may go this route too. Thanks!
Jon

[jdbnsn]

New question, how does the flame sanding thing work? I tried it on a little scrap with a butane torch and kept the flame away from the plexi using only heat, but as soon as it began to heat it bubbled and turned black. Hmmm, more practice perhaps?

[tybrenis]

Hey,

I can only give you a few tips. I assume you saw the flame polishing technique in my work log, right? Just remember to not get too close, and ALWAYS keep the torch moving. A butane torch isn't really ideal for this kind of application, professionals use a hydrogen/oxygen torch.

[jdbnsn]

Yeah, I saw your worklog yesterday again which made me think to try it. Hmmm... I have a heat gun paint stripper here that I have never used before. Maybe I'll give that a go.

[tybrenis]

Yeah, I saw your worklog yesterday again which made me think to try it. Hmmm... I have a heat gun paint stripper here that I have never used before. Maybe I'll give that a go.

Tell me how it goes, I've never tried using a heat gun for polishing.

[jdbnsn]

Still, no luck. I used a wagner power stripper which worker better than the butane torch, but I still get bubbling before the plexi smooths out no matter how slowly I have tried. I guess I just need to keep practicing.

[bobthecarguy]

Hey, just tried the flame polish thing. All I had on hand was a small propane torch for soldering, but it actually turned out quite good! Not a very hot flame so it required some close contact and I made off with only one small flaw! I did the full 80/120/220/400 sandpaper routine first and that made it pretty easy. I will be posting the pics in my worklog soon, this was one area that had me a little scared but now I wanna flame polish everything!

[jdbnsn]

Hey, just tried the flame polish thing. All I had on hand was a small propane torch for soldering, but it actually turned out quite good! Not a very hot flame so it required some close contact and I made off with only one small flaw! I did the full 80/120/220/400 sandpaper routine first and that made it pretty easy. I will be posting the pics in my worklog soon, this was one area that had me a little scared but now I wanna flame polish everything!


Yeah, I'd love to see your pics, I am thinking that I was not doing enough sanding. I'll follow your lead and try again.

[tybrenis]

Yeah, I'd love to see your pics, I am thinking that I was not doing enough sanding. I'll follow your lead and try again.

Sounds good, but we NEVER sanded the edges when I polished them... then again, that was a professional torch. :D :D

[bobthecarguy]

Posted the pics in the worklog.

What I would like to know is how to cut a nice smooth edge, the edge of the panel that was cut at the Plastic shop required little or no sanding but my Jigsaw cuts were BRUTAL! I am sure I was using the wrong blade for the job as it was actually melting the Plexi and partially resealing the panels behind the blade!

[jdbnsn]

Posted the pics in the worklog.

What I would like to know is how to cut a nice smooth edge, the edge of the panel that was cut at the Plastic shop required little or no sanding but my Jigsaw cuts were BRUTAL! I am sure I was using the wrong blade for the job as it was actually melting the Plexi and partially resealing the panels behind the blade!

Saw your pics, well done! As for the cutting, great question! I originally tried a table saw which didn't seem to work well, but might work better with a different blade. I use a band saw now and my cuts are much like the ones you describe and require lots of sanding. Maybe someone could throw us a bone on cutting techniques or proper blades?

[tybrenis]

Saw your pics, well done! As for the cutting, great question! I originally tried a table saw which didn't seem to work well, but might work better with a different blade. I use a band saw now and my cuts are much like the ones you describe and require lots of sanding. Maybe someone could throw us a bone on cutting techniques or proper blades?

Hey guys,

More tips and what-not. The edge sraping in your log was great, thats what I forgot to mention. Really, any type of metal with a nice edge will work, but pros use a small rectangular prism of cobalt, since it holds it's edge very nicely. You'll want to edge scrape after cutting.

For jigsaw and bandsaw cutting, you will want to use a metal blade, one with very high teeth. These tools aren't really ideal for plexi, but with a metal blade they do pretty good.

Always remember to never flame polish an edge that is to be glued, it screws everything up.

And finally, you will want to cut all acrylic that you can on a table saw. This is what the pros use. You will want a blade with the following specs:

- "Triple Chip" format, this helps IMMENSELY
- Carbide tips
- Atleast 80 tooth
- 0 degree rake/offset

Blades like this tend to be pricey, but trust me, are very well worth it. They do not melth the plexi and make nice, almost finished cuts. After they are cut you will just want to scrape them, glue what you need to, and then polish.

[guitar.child]

awesome I love this guide my new window is now complete. tahnks

[Cannibal23]

******** heat bending into tricky spots.

if you have been worried in the past about not cutting through the handle on your side panel because you would need to bend the plex to make a new handle here is how to do it.

take the paper off the plex

fasten your sheet of plex to an uncut side panel that matches the one you are going to or already have cut through. soak a clean cloth in water. it dosent have to be freezing cold but a lil chilly. place that on a part of your plex that your not bending as you will need to get your hands on it quickly. heat up the area to be bent with a heat gun at close range. you should heat it enough that you see it start to deform a a bit. remember to keep moveing the heat gun arround or you will get bubbles. once its hot enough all you have to do is take the wet cloth and wipe it with a little pressure (enough to bend the plex) where you want it to be molded. this allows you to hand mold some tricky spots without burning your fingers. the fact that the soaked cloth is a lil chilly should help to freeze the plex in the exact position that you were pressing it into.

i used this method 2 days ago and i am very happy with the results. hope that helps someone

[Erwin265]

Hi guys,
I've been surfing; trying to find as much info about flame polishing as possible, when I came upon this site and noticed the "butchering" that you've been doing on Perspex [I'm not sure if you're familiar with this name - it's what we call it in Australia].
I make display cases out of Perspex for customers [something to fund my numerous hobbies].
The BEST thing to cut Perspex with is a table saw; properly set up - with a dedicated blade that you use ONLY for Perspex. I would suggest the blade have at least 80 teeth [less works OK, but you have to move the sheet through VERY slowly].
Another thing you need is a zero clearance throat plate. If you're not sure what this is; where the blade comes through the table, there is an insert that sits in a rather large opening in the table top which can be removed [for access to the saw - for blade changing, etc]. The gap for the blade in this factory plate is quite wide [to allow you to tilt the blade for angle cuts] - make a new one out of wood - with no gap and start the saw with the blade fully lowered; then all you need to do is slowly wind the saw blade up to make a zero clearance plate [be sure that the new plate is held down safely [ie. NOT by hand!!] as you raise the blade [perhaps a few pieces of wood and clamps strategically placed]. The new plate also need a "splitter" - something to stop the material closing together after having been cut, behind the blade [this is very dangerous as the blade will grab the material and throw it with gteat force at the operator]. All this is; is a thin piece of wood [the same thickness as the blade] glued into the back of the saw groove that has been extended so that it won't get ripped out by the blade if it is fully raised.
Lastly, raise the blade only slightly higher than what is needed to cut through the Perspex sheet.
Just one more point; a jigsaw blade moves much too fast and will inevitably melt the Perspex [as described by another] - if you have no other choice of tool, try using a variable speed controller [available from most woodworking suppliers].
All the best - let me know how you go.

[Maz]

if you have the bottle of glue with the flexible needle on it and your glue is very watery.

you should have all of that.

get our edges as flat as possible and set them up. take your bottle and fill it 1/4 of the way to the top. squeeze out most of the air and turn it upside-down. release the bottle from your fingertips slowly and the liquid should stay in there.

when you get good at this practice, glue your piece. take the bottle using the same technique you just tried and put it along the edge where the two peices meet. though capillary action, the glue is sucked into the joint and you havent spilled a drop thanks to that technique.

for those who have gotten glue on your case or may in the future, my good friend jamaul (works at eagle plastics where i interned for a summer) taught me that one.


oh and if you use petrolium jelly on your bit while drilling it makes an opaque hole, or so im told.
and with a scroll saw , as long as it has a speed controller, is great for detail work, but i wouldnt use it to cut anyhing big, nor straight lines.

[Cannibal23]

thanks for the contributions guys.

[Maz]

A note about flame polishing.

you CAN use a propane torch. just find a way to plug the holes on the side of the nossle so oxygen cannot enter. (I used Aluminum foil) this is what makes the flame really hot. just go over the edge as if you were painting it and you should have a really nice edge after a few passes. it it looks good, stop. you dont want to overdo it.

Erwin could you post a pic of one of your cases? that is pretty much all i did for 3 weeks straight. well that, and clean.

[faolan01]

I've been doing a bit of work with plexi lately..mostly screwing around to see what works and what doesn't..and I've figured out a few things others might find helpful.

I've found the easiest way for me to cut designs in plexi is by using my dremel at low speed with a 1/8 inch drill bit and the line guide attachment. I've tried thicker bits, but they tend to chew up the plexi instead of making a nice cut and cause it to vibrate so much I was worried it might break the plexi. A smaller bit works well for finer lines and detail work, but tends to melt the plexi which builds up on the bit. The smaller bits also break much more easily (I've snapped 2) if you aren't careful or try to cut too quickly.

For smoothing out edges in a cut design and adjusting the shape of cuts, I've found that a metal emory board (basically an oversized nail file with a fine grit) works really well. You should be able to pick one up for about a buck at someplace like CVS. Follow it with 2000 grit wet sandpaper to get the edges really smooth.

I also saw someone ask about using paint on plexi and saying they were having trouble making it stick. I've had really good luck with the Krylon Fusion spray paint. It's designed to bind well with plastics. If they don't have a color you like you can also try using a medium grit sandpaper, around 200 grit, to scuff the plexi first. It makes the plexi rough enough for the paint to stick and the paint will fill in the scuffs making the plexi look smooth again.

[Cannibal23]

if you must paint it remember to paint on the inside part so if it gets a ding in the side of it that the paint wont chip off. my mom used to do signs to look like stone with an airbrush some plex and i think the paint was acryic paint

[yusaku]

i would also suggest possibly some e6000 or similar glue its basically clear Silicon sealant in a scweeze tube. Also polycarbonate would probably be the lightest if weight is an issue, for carrying to lanparies etc. some one should do an all polycarbonate / carbon fiber mod!

[tybrenis]

For gluing acrylic you will want to use a solvent glue, such as a weld-on from a brand like IPS. I personally just use methylene chloride, this is my favorite solvent for gluing most plastics. It works great on styrene, acrylic, polycarbonate, PVC, and more. I do not recomend trying to glue acrylic with an epoxy or silicon, this is a bad idea.

[bennyrux]

For what it's worth, I've read (never tried) that others have had success drilling holes in plexi in reverse. I don't think drill presses can be made to turn in reverse, but corless drills and other electric hand drills can be switched to turn in reverse. It prevents the drill from taking out a chunk when you drill thru the back.

-BennyRux

[Cannibal23]

when i drill mine i just use a drill press with sharp cobalt bits. wich is probably a little over kill but it works well for me. typicaly i cut the design out of the side panel first and get it prepaired and then duct tape the paper coverd plex to the underside of the panel. then i drill the holes in the metal and the plex at the same time so i know they will match up for sure. i dont use the rubber window trim, i just bolt the window onto the inside of the panel wich works out pretty good. if you pick good places for your bolts then you dont need to worry about the edges of the metal sticking out a little and cutting you. this also makes it more convieniant for cleaning if the window gets dirty you just unbolt it and wash it

[ajmilton]

I've been lurking for a week or two, decided to toss in a little information i found on working with plexiglas - the "official" plexiglas website has a couple of pretty decent manuals on fabrication and forming:

fabrication:
http://www.plexiglas.com/literature/pdf/134.pdf

forming:
http://www.plexiglas.com/literature/pdf/135.pdf

i haven't worked with any of it yet but there's lots of charts and pictures and whatnot.

[fragged]

I havnt read all the replys but I thought I might mention the methods my old school used to use to bend acrylic. Both methods we were told to allow the acrylic to heat till it was flimsyish (experiment), and then bend it slowly, once we have our angle, we had to ether manually hold it there or use a vice, or scrap wood to hold it till it cooled down (Took about 5 minutes), also, Acrylic is a soft plastic, that is you can reheat it till your content.

Sharp Bends
They used a strip heater which is basically a heater that heats about 30cmx2cm, and told us to use metal to block off the heat we didnt need (of course, we used gloves) this was capable of just about any angle I tried,

Round Bends
The second method seemed to be custom made for the tech room, they had another wall mountable thin heater (30cmx2cm) and two pieces of wood about 15cm above it on rails so they could move in and out as below
______...______ <-Wood
..-----...------ <-Rails
...\________/ <--Heater

(Excuse the crappy ascii art, the forums clear out all unneeded spaces :( (.'s are imaginary spaces :))
so basically you heat up whatevers hanging between the wood pieces, which move in and out to allow you to control your design

Hope this helps somebody,

-Fragged

[Acey]

I used jigsaw on acrylic/plexi coupled with Black & Decker's Piranha blades. Forgot the full code but there's 2 blades with 1xx-1 (finer) and 1xx-2 that gives clean cuts while the other 3 remaining blades are for wood work.

[drcrash]

You can vacuum form acrylics into all kinds of shapes, on a homemade machine that's not expensive or difficult to make.

Here's a shape I did recently, using a piece of acrylic fluorescent diffuser panel from the hardware store, because I like the funky texture:

http://i136.photobucket.com/albums/q176/drcrashpix/miscmasks/crackedice3cropped.jpg

http://i136.photobucket.com/albums/q176/drcrashpix/miscmasks/crackedicecropped.jpg

In the pictures, the acrylic is around the plaster life cast I molded it around.

(The yellow stuff around the nostrils is modeling clay I packed there to keep the acrylic from pulling in too much to get it off. The green cast in the second picture comes from taking it under fluorescent light and not color-correcting it.)

[Zephik]

That looks like it would be perfect for a mars mod! Put it on top of your case and make your case look like mars. Since you know how the rumors and pictures go about the face on mars. ^^

-SF

[intergalacticman]

as far as cutting goes, a jigsaw's vibration will crack the plexi and melt it from the friction. a hacksaw will only work if the peice is small, or it will become stuck, the way i did it successfully was by scoring it multiple times and breaking it. although it was time consimong and messy, it worked

[tybrenis]

That is not true intergalactic man. Acrylic is cut well with a hacksaw using a metal blade. I don't know what happened to you, but generally hacksaw are decent for cutting intricate designs.

Also, you can only use the score and snap method for acrylic 1/8" and thinner.

Also, using the proper blade with the acrylic correctly set up for cutting, a jigsaw will not break it as long as you take the necessary precautions. Also, acrylic will not melt if the jig saw is at the right speed. Any faster with the wrong blade would hook the acrylic, shake it, and snap it (probably what you did).

[intergalacticman]

about the hacksaw, i dont know, but, a jigsaw isnt the best way to go, a finer blade will melt the plexi, and a slower speed will shake it. i would know this because i cut plexiglass frequently. as far as gluing though, i agree, but dont use a glue gun or other stuff like that, but i use gorilla glue, and that seems to be mighty stable



That is not true intergalactic man. Acrylic is cut well with a hacksaw using a metal blade. I don't know what happened to you, but generally hacksaw are decent for cutting intricate designs.

Also, you can only use the score and snap method for acrylic 1/8" and thinner.

Also, using the proper blade with the acrylic correctly set up for cutting, a jigsaw will not break it as long as you take the necessary precautions. Also, acrylic will not melt if the jig saw is at the right speed. Any faster with the wrong blade would hook the acrylic, shake it, and snap it (probably what you did).

[Truffles]

Another method of cutting is Laser Cutting. It is extremely accurate and gives a good finish. It also takes much less time.
My workplace has a cutter which can fit up to 1100 x 1100 (mm) sheets. This is large enough to cut most things that I need to. You can get larger ones although obviously the price increases with size. The cheapest decent one that I've seen is around &#163;14000 (I believe that is about $27000).
You can plug your computer into them and they'll cut whatever you design with a beam of light. I wouldn't expect many people to want to spend that much money themselves, but it may be possible to persuade your work/school to make the investment for you ;)

[tybrenis]

I am currently building a CNC machine - it will be a CNC router. Eventually, I will use to it to cut out a new CNC machine for myself: this one will use a laser, probably CO2.

[Zephik]

So your making a CNC machine so it can make you a CNC machine? ...my god... thats brilliant!

[tybrenis]

So your making a CNC machine so it can make you a CNC machine? ...my god... thats brilliant!

Hehe... yup. As soon as my machine is done, it will be used to cut and drill higher precision parts that will be used to replace the hand made ones in the machine. Eventually, I plan on building a CO2 laser and then making a second machine that uses a laser to cut patterns in metal.

[sirkillalot617]

duno if anyone already posted this but heres somin for gluing plexi together
http://guides.pcapex.com/modding/diy_acrylic_cement.php

[Commando]

Man, a laser cutter sounds great. All I need to do now is sell my house. I might need to run that one by the wife.

[tybrenis]

Hehe. Just build you own. My router is costing less than $400 to build, everything included. Add a laser to that and its still probably less than $1200.

[Moofaa]

Ok, so from reading the information in this thread, I can pretty much cut acryllic to my hearts content just like the pros...

But what about painting? Specifically I had a mod idea that went something like this:

Sparing lots of details, I want a plexiglass side window that is transparent, but not so much that you can actually see the PC parts inside. Thats easy enough and could be acheived by using the methods to make a 'frosted' look.

Heres the kicker, I want it to look something like an early night sky, that is, I want a light blue that fades to almost black towards the top. (the idea being to kit-bash a model of a moon and mod it into the upper part of the plexiglass, and wanting perhaps to set a smattering of white LEDs for stars).

How to do this? I was thinking of sandpapering the plexi, to give it the frosted look, then attempting to spraypaint this side (it should stick since its roughed up?). I've heard there are some 'transparent' paints, dont know as im not really an artist.

[tybrenis]

That would be a bit tricky to do, but achievable. Yes, you would have to "rough it up" a bit before you sprayed it. They do indeed make transparent paints, but I have only seen them for airbrushes, never in spray paint form (that doesn't mean they don't exist, I just haven't seen them!).

Some transparent paints:
http://www.pearlpaint.com/shop~parentID~5486~categoryID~5484.htm
http://www.pearlpaint.com/shop~ocID~~parentID~5483~categoryID~5477.htm

[Moofaa]

Yeah lol, airbrushing is out I think. The paints not bad at all cost wise, but I would need a compressor/airbrush as I dont know anyone with all that stuff, and I dont plan on spending that much money for something I would only use for this project.

Maybe a blue tinted acryllic panel..sanded to get that frosted look, then use a dark blue/black spraypaint on it, spraying it so its denser towards the top/lighter at the bottom.

and of course, it would be lighted with a CCFL at the bottom... I might test this idea if nobody comes up with a definate answer. Have to order that acryllic online tho, no places around here sell it.

[MattMan]

Hey, I just did some work with some Plexi, and I know when I asked about it no one really told me if it was possible or not. And if this was previousely stated in this thread I am sorry.. I only had enough time to read through half of it.

If the advise that I am about to post is already posted, please PM, and I will edit or remove it if possible. Or any Admin is welcome to move it. My feelings wont be hurt.

A laser cutter works very well one plexi glass (they told me Acrylic specifically) which it did do the best. this device is alot easier and faster than any other device. the problem is having it accessible to you. Luckly I am fortunate enough to where my major has a full scale shope with paint booth vaccum formers metal and wood shop. and a laser cutter. basibly it super heats a laser onto a material to eitehr score it or cut through the material.

it works with any materal (metal, wood, or plastic) but certain types of clear plastics will burn to a nice brown instead of staying smooth and clear. The laser cutter is very accurate, and makes every cut smooth. working for cutting out, etching and engravings. Just have to know how to set it up.

best used with Illistrator to make your designs on.

Hope this was of help to anyone who needs it. Later.

[tybrenis]

Yes, CNC controlled lasers work best to cut acrylic as when your piece is done, it requires virtually no finishing work. Not only do they have the accuracy of a CNC and a laser, but the laser's intense heat leaves a beautiful edge that can otherwise only be attained through the use of flame polishing.

[_ferry_]

Just saw this topic, and maybe someone has mentioned it before, but acrylic wont melt while sawing it when you put masking tape (that tape looks like paper) on top of it. Don't know why, but it works :D
You can also draw the cutting line on it, and it prevents scratching.

[Intrance]

Just one on the cutting of Plexi.

I have just started doing some work with it (only small bits) but had a real nightmare cutting with the Jigsaw and dremmel (too much melting, to the point with a jigsaw fine blade that it welded itself back together behind the blade!!). So using a bit of ingenuity and a limited tool set I found that a tennon saw cuts the stuff blilliantly. The teeth are fine enough and the cut is not too rough, so a rasp and file and sandpaper does a fine job!! It is also very accurate on the straight cuts, and for the curves I use a coping saw.

[_ferry_]

And if you have troubles with cracks in your acrylic while making threating in it, for example with a m3 bolt in the side of a 5mm panel. Just rotate your screw quickly from left to right, and combine that with screwing it into the acrylic.

When you do this, the bolt gets hot due to the resistance, and it heats up. The plexi will melt a little araound the screw because to that, and plexi which melts wont break....

[Cannibal23]

wow who would have thought that my little wenie post about some tips with pmma would get 14000 views... thats insane but at least its makeing someones life easier. :-)

[SgtM]

Anyone have any suggestions on frosting plexi with sandpaper?

[tybrenis]

For frosting acrylic, you'll want to wetsand the whole way. This will eliminate swirl and scratch marks.

Start with 120 grit, then 220, then 300 or 400, and you can go higher if you wish. However, I've found that 400 to 600 is generally a very nice look.

[slytherock]

Only advice I can had: make it uniform. dont go circles in one area, then straight on others. I'm thinking of something; maybe a polisher can make a good job on this... I will have to try it.

[Cannibal23]

ha ha an 18000 view thread is not bad for some dude with 1 rep eh lol. im so glad that everyone is helping out in here and getting the help and advice that they need. plex can be a little scarry when you first start out and are affraid of making mistakes.

[blueonblack]

I haven't had the opportunity to work with this stuff (I will call it acrylic as that seems to be a group term), but am planning a project with it and have learned that there are two kinds: extruded and cast. Given the differences I have read about I was surprised that no one had mentioned it. (They didn't, did they?) Cast acrylic is more expensive, though not prohibitively, and is supposed to cut/sand/form/machine and polish MUCH better than the extruded type. Supposed to have a higher density and higher melting point. Does anyone have any experience with these two different types of acrylic?
________
Jaguar Xk (http://www.ford-wiki.com/wiki/Jaguar_XK)

[Xperiment]

This link should give a fair bit of info on the differences between the two types.

http://www.acrilex.com/question2.cfm

[blueonblack]

Thanks very much, very helpful. :)
________
Life saber (http://vaporizer.org/)

[Twigsoffury]

What about Polycarbonate?

I'm having alot of problems trying to cut through the stuff its 1 3/4" thick.

any tips? It's eaten two hole saws and a couple drill bits. oh and a jigsaw blade. If you stop cutting at any point with it in contact the crap just welds itself around it.


strangest thing i've ever seen.

[A3DSAIL]

Polycarbonate (Lexan) is a thermoplastic that can be typically cut with a tablesaw using a circular saw blade with carbide teeth, utilizing the "triple chip" tooth design, as the preferred method. Blades for cutting thicker polycarbonate should have three to five teeth per inch with a hook or rake angle of 10- to 15-degrees. Circular saws should be run in the speed range of 6,000 to 8,000 fpm

Band saws can be used for trimming formed parts or irregular shapes. They should be run at 2,500 to 3,000 fpm and have 8 to 12 teeth per inch. Coarser (larger) blades perform better with thicker gauge polycarbonate sheet. Proper support of the part to be trimmed is important because vibration may induce cracking.

Routing can put a smooth edge on polycarbonate sheet and can also be used to cut curved or irregular shapes. Routers with at least 1-horsepower motor and speeds of 20,000 to 25,000 rpm are preferred, used with carbide-tipped or high speed steel router bits. Stock must not be feed too fast to prevent vibration and cracking. It is important to feed the sheet against the rotation of the router bit and to provide a fence for sizing when making straight cuts.

Edges may be finished by planing and sanding, which provides a smooth, matte finish, but flame polishing polycarbonate is not usually acceptable. Instead, after sanding to remove all the tool marks, a cloth dipped in a solvent such as methylene chloride can be used to carefully wipe the sheet's edges. Do not allow the solvent to drip on the sheet face as discoloration will occur.

Source: http://www.plasticsmachining.com/magazine/199609/polycarbonate.html

[SXRguyinMA]

I jsut placed an order with www.delviesplastics.com for some materials for my project, and this thread was very helpful! I order a bunch of extra, because I'm sure I'll mess up. But I'm going to take my time and see how it comes out!

[kalor_alros]

Lastly, where can you buy large sheets of it? I think i looked at lowes and Home Depot and neither had it, I had to get some from tybrennis online. But if I needed a large sheet, the shipping would be way too much?
Thanks a bunch all!

Depending on quantity, I found a couple places to check out, the prices seemed alright to me... the first, only if you're ordering in quantity, because they have a minimum price per piece (which seems dumb to me, but I guess that's why I don't sell plexi ;) ), the second seemed good. So:
http://www.professionalplastics.com , and http://www.delviesplastics.com , they are really the only two that I've looked in-depth at.

And a question of my own. Working with plexi, and wanting to make a waterproof enclosure. The panels are squared up, and I am concerned about the joint, first. I was thinking of making a square bracket with more plexi, and using ISP Weld-On to seal the pieces to each other. Is there a more effective way to do this, and would this work?

The second. I have two tanks of water, and need extrusion pipes running between them. The first part of this question is this... how far apart should they be? The are ID .250", OD .5", the walls of the tank are .5". The second part is making the holes where the pipe passes through waterproof. I've looked for gaskets, but that seems to be the wrong application. I was thinking of getting something like a barb from a watercooler or pump, and seating it in the hole, then connecting the pipe, but I'm not sure that will allow liquid to pass through them. Suggestions?

[cvitullo]

I was thinking of making a square bracket with more plexi, and using ISP Weld-On to seal the pieces to each other.
I don't see why that wouldn't work, as long as you sealed it well enough.

And after reading through all of this, just thought I'll add my experiences with lexan/acrylic. We used ridiculous amounts of lexan in my high school robotics team, and a dremel works great for cutting it. If you use a high RPM it leaves a fair bit of melted lexan on the edge to file off, but I didn't have any problems with heat distorting the sheet (1/16th inch, btw). Acrylic seems to be waaaay worse from a strength standpoint. I tried drilling holes through it, and it cracked every single time. I've seen some tips recommending drilling backwards, but I haven't tried that. From my experience, I don't think it'd work that well. Lexan's definitely a lot springier than acrylic, which I suppose could be a bad thing if you're using thin sheets over large areas, but 1/8th or 1/4 inch is pretty rigid. Hacksaws work great for rough cuts, and tinsnips work really well for small cuts. I used a bandsaw to cut a 4 foot section with no problems, just make sure to use a fine-toothed blade.
Be careful bending, it's really easy to go overboard on the heat. We had an absurdly ****ty bend in one part because we used straight up heat with no good edge to bend it on, so make sure you're prepared.
Like I said, drilling acrylic is frustrating. If you just drill normally, it cracks at least 95% of the time. I got 1 hole out of 9-ish to work well, but that's the only one I've ever succeeded with. Lexan has no problems, just drills straight through.
Also, if you ever mix up lexan and acrylic, just wobble it. If it makes a "woob-woob" noise, it's lexan. Only works for larger, thinner sheets, though.

Wow, that was a lot more than I thought it would be.

[AntraxLife]

anyone know how to frost plexi... anyone who can show or explain that to me ?!? :D im just a noob :D