HI i just have a quick question,
I'm modding an old compaq case and the paint on it is pretty thick, do i need to sand all the paint off before repainting? like get to the point where i can see the steel?
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HI i just have a quick question,
I'm modding an old compaq case and the paint on it is pretty thick, do i need to sand all the paint off before repainting? like get to the point where i can see the steel?
Not at all - you CAN if you want to - but if you go that far you'll need a special etch-capable primer for bare metal. There's no reason you can't just sand it down a little to clear the surface of any little imperfections and provide a key for the new paint to get a grip on. A layer or two of a decent build primer, sanded between and after coats will help you get a REALLY smooth finish....
Something else to consider is that the case may well not be painted at all - it's very likely it'll be powder-coated - in which case sanding it to bare metal will be a HUGE job....
well... uh, ive been sanding it by hand and it has been super difficult. In some parts im at the bare metal and other not...does this mean i need to sand it all to the metal and use that special primer? its only been the door, the rest of the case, well now i know better and wont sand it all the way, however parts of the door are already at the bare metal so should i just sand it all the way? Also what is powder coated? some parts of the door i sanded down way fast to teh metal, even before i realized i was sanding the metal and other parts are taking forever to sand down.
I used a palm sander (orbital) on my powder coated case, and it wasn't too bad. I either used 80 grit or 60 grit sandpaper.
ive been using some aluminum oxide fine sandpaper from m3. it doesn't tell me grit on mine. It just says fine, good for metal and wood. Does this mean i am sanding everything to the bare metal before i can add primer and paint?
You don't want fine sandpaper for heavy sanding. For that, you want coarse, or, at the very least, medium.
Well, i have sanded it to smooth already, i just want to know if i need to finish sanding this to the metal now that i have roughly 1/7 of the door sanded to the metal?
I'd suggest stopping where you are - put a couple coats of primer on, and rub them down with the fine paper -ideally, with soaking wet "wet'n'dry" and see how it feels - not looks - be your own judge - if you think it'll look ok and the primer appears to be holding properly to the case then start with colour
whats wet'n'dry? do i just wet my sandpaper? or pour water over the primer coat as i sand? or is it a product...?
Wet/dry sandpaper is sandpaper that can be used wet or dry. Here's how I would proceed. If you have most of the panel sanded already, you might as well go all the way.
Primer - dry sand with 400 grit. That way your base coat has something to bite to. You don't want the primer to be totally smooth, or else the base coat won't stick.
Basecoat - Dust coat until you get full coverage. Don't try and hog the paint on. It'll run. No sanding necessary unless you have dirt nibs. In which case, only sand enough to get the nibs out.
Optional - airbrush artwork or whatever else you're doing to the paint job.
Clear - after your clear coats are done, wet sand with 1000, move to 1500, finally 2000. Then use some 3M fine cut rubbing compound, followed by polishing compound. Wait about 30 days, and wax with car wax. Waxing sooner will seal in the chemicals that need to cure off and will basically turn your paintjob to gel.
The end result will be a mirror shine with no orange peel. Make sure you follow the directions on the can regarding coat times to the letter.
My latest paint job - http://www.thebestcasescenario.com/f...516#post252516
Yeah, so, I'm just gonna go ahead and send my case to you so you can paint it Kgreatthx! ;)Quote:
Originally Posted by SgtM
o wow... I dont need a mirror shine but thats very good advice, i will take note for when i do a case that needs the mirror shine. Im currently just aiming for a glossy, smooth black surface. I still need to do some researchin on how to do the glossy black, also trying to figure out if i can get the plastic front the same glossy black.
There are two ways to get a good glossy finish - the first is to use Gloss Black paint (no surprises there) as opposed to satin or matt black - the second is to use clearcoat after the black - then it won't really matter which black you use as the glossy shiny finish will come from the clear...
As for the plastic - you can paint that no problem - just give it a rough sand first to give the paint something to grip onto - if you want to be extra perfect - use a plastic primer on it first although that's not really essential it can help with long-term wear
Cool thanks for the great advice. I will give it a go :) Thanks again guys
OK i sanded it and the paint is sticking, however, i am having issues with paint, im getting wierd textures that look like scratch marks where i sanded it before (this is plastic). I tried sanding down teh paint on the pastic till it was smooth and repainting it but the same thing happens. Am i spraying wrong or sanding wrong?
You'll have that with light coats. As you add more coats, you'll notice that they go away.
I have given it 3 coats and its all been fairly thick imo and i still have that texture. Also, now it seems that in certain areas im getting something that looks like cracking but is actually just thick paint? Also im getting some bubbles in parts and its leaving a strange texture on the paint job.
The strange texture and bubbles is due to a chemical reaction. You'll want to sand it down. Check the can for coat times.
OK, thanks. I sanded down the bubbles and repainted, So far it looks good.
I went to check it this morning, but it seems that i sprayed on a coat thats too thick? i have areas that look like stripes because some parts are thicker coated than others will i need to sand this down and recoat a couple more times? I ahve like 4 coats on this piece of plastic already...
Easy fix. Spray a few more coats to really build it up, and then sand it all smooth with some 400.
O.o wow i need to get another can then... i need a lot of practice with the rattle can... this stuff is really hard to work with. thanks, i will try it again :-/
Just keep practicing and you'll get the hang of it. Rattle cans are a bit tricky but with practice you can get great results with them. The best advice is to read the intructions on the can and follow them closely, apply light coats to build up the thickness and color sand with wet/dry sandpaper. Keep the paper very wet and put a couple drops of dishsoap in the water.
what is the diffrence between wet sanding and dry sanding beside wet paper? Ive been cheap so i only have fine paper from m3, i dont even know what grit it is...
Pictures Please :)
of the sandpaper? or my awful paintjob? >.>
The "awful paintjob" (by the way .. I would call it the "unfinished" paintjob) ;)
wet sanding uses a different sandpaper, it's not much more expensive than what you've got. But the grit is rated by numbers, the bigger the number the finer the grit. It also lasts longer when you use it wet. You can get it in packs with a variety of grits at some home centers, hardware stores , or auto parts stores.
could not get pictures, camera is in cradle charging now, will try to get some up by this weekend. Is there some sort of product for touching up paint? I realized that the masking tape im using when i remove it leaves some of the primer showing so i have a thin white line on part of my case sidepanel. Should i jsut use permanent marker?
When it comes to paint Commando is your man .. check out some of his tutorials ... you'll save yourself time and heartache:
http://www.thebestcasescenario.com/f...ber.php?u=6128
CB
I actually sent commando a pm a while back asking about one of his paintjobs since the case he painted was the exact one im working with now. However, i have yet to hear from him.
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its hard to see the imperfections, but on the one of the whole body i have a series of scratches under the paint and on the front plastic part theres some wrinkly areas and such. However, the 400 grit wet sandpaper really helped, thanks for the suggestion! It was a lot better than before.
Body shops pretty much start with 400 grit for color sanding and end with 1200 or 1500 grit before buffing. So the finer grit you can get and use the better the end results. But be careful you don't sand too much with the rougher stuff, or you get to start over.
yea, i am going to sand the top again with 400 grit and repaint it. After that I'm out of paint and i dont really have a budget to go out and get more rite now. :-/ However its a lot better than when i first started so i need to thank yall a lot of your help.
That's what we're here for, helping each other out. It's why I like this site so much more than a lot of other modding sites.