Help needed for 3D casting for a costume.

[d_stilgar]

I know this might not be the right place, but I need help.

I want to make a 3D mold of my girlfriends legs to make a mermaid fin costume. I really do not know where to start. I know that I need some sort of 'paste' or 'gel' that sets into a rubbery consistancy and that I should apply that to her legs and torso and then wrap that in plaster strips so it will have a hard case around the mold of her body.

From here I do not know how to progress. The end result should be a perfect fit on her legs and torso, but also have the outside look like a fin. It would also be nice if it were neutrally buoyant and waterproof. It of course needs to be flexible since she will be moving in it.

My idea:
I could recast her legs from the mold, and then sculpt the fin out of a hard wax or possibly some other hard material. I could then make a mold of the sculpted fin. Finally, I could take the cast of her legs and suspend it in the mold for the fin. I could then pour in the stuff that turns into a foam rubber fin that I could paint.

I do not know what materials to use or what they are called. I am skilled and patient. I like to do it right the first time, but will do it over and over until it works. I need help on what materials I should be looking for and help on the process unless noone sees a better way. Thanks a million.

-Daniel

[Omega]

I would imagine nobody here has experience with that...

Watch mythbusters. They do that kind of thing in a few of their episodes but i forgot the names of everything and how you're supposed to do it.

[opengswede]

hmm, all the rubbery materials that you can mould I can think of are probably too hard to make it look like a flexible fin. I'm guessing you what your g/f to be able to flip her fin using her legs.

The solution I can think of is cloth, a textile that looks the way you want (you could paint it as well). Perhaps reinforced with steel wires or a metal frame to get an even narrowing of the fin as it runs down her legs. The difficult part will be the knees which is where the "flip" will be generated.
Try a firm piece of textile, or perhaps the material that is used in scuba gear (wet suit) if you can afford it.

This way might not support a close inspection though...

However, you might get away with it if you dress the textile with something on the outside... perhaps small pieces of plastic (to get the fishy look :)(scales)).

The tip can be moulded in platic or plaster, depending on what easy or durable you want it. Only you know what your plans with this lower body-work will lead to...

-.erik

[d_stilgar]

Hard rubber is for making a hard, but flexible mold to cast. When you finally cast it, it would be with a softer material.

[tybrenis]

I am also kind of looking to get into this. I am certainly no expert, but you could try...

Use strips of plaster cloth and cover her legs in them. Then slather on some plaster, and allow it to dry. Cut it down the middle so you have two molds.

Then you could cast that in something like ballistics gel (thats what mythbusters uses).

I dunno, just my ideas. Do you want her to be able to fit her legs back into the thing?

[d_stilgar]

Yeah. That's really the whole point, to make a costume.

[opengswede]

ballistic gel will probably break if one tries to move inside it, it is fairly rigid. It is also expensive. Apparently I don't really understand what you want, how the material is supposed to look like, act like on touch, move in relation to underlying motions, etc.

There might be trade-offs that you have to consider.
And again, I'm not sure if you'd find a material that is "perfect", at least not one that is mouldable. I'm still voting for wet suit material, it handles water, it feels slippery on touch (if wet) it can probably be painted easily, it is easy to cut and with a metal foundation it can be shaped the way you want it.

unless you really want to mould something. then a gel of some kind will probably work, just bare in mind the flexibility, enough stress and it will fall apart.

I'm not saying I'm an expert so take my word with slightly more than a grain of salt.

-.erik

[AKA_RA]

why dont you use latex? i mean, i dont know anything about it, but i thought that is what people usually make this sort of thing out of. is it expensive?

[Mach]

I believe that you are describing alginate. The same stuff that your dentist uses to make impressions of your teeth. Alginate goes on first and then a layer of plaster bandages can be laid down on top to form a shell. I don't remember all the key steps but you can pick up the book: Techniques of Three-Dimensional Makeup - by Lee Baygan

Also check : http://www.makeup-fx.com

The learning curve and the costs for what you are describing are very steep. You might want to check here first. $250 will be minor compared to how much you would spend trying to do this with custom rubber compounds (some of which can cause allergic reactions...:eek: )

http://www.mermaidrentals.com/mer.htm (doesn't appear to be netscape/mozilla friendly)

[d_stilgar]

I've been to mermaid rentals and I also emailed the guy there with some questions. He politely declined releasing some tips --which is fine he makes a living off this. If you look at the girl swimming you can see how bad the fin is pushed between her legs. I don't want that. Plus, the fins that you can buy just don't look as good.

I would rent one, but I want an exact fit. My guess is that he sells them for around $3,500. I'm not sure how much of that is profit, and that number is a guess, but the deposit is $2500 for a rental, so I might be close.

I also just want the challenge and want to learn how to do this sort of stuff.

[crazybillybob]

For Life casting you want to use Algen or some quick set latex.

Then make your fin out of plywood or blue foam from the home center. You'll have to make a casting of your gF legs (use plaster in the algen mold that you made). Now you'll need to make a big mold (includes the fin and the leg section)so that you have one peice. The Tricky part is that you need a void between the plaster legs and the outer mold. Check out WilletFx's work log and you get the Ides Animatronic eye Prototype page 8 (http://www.thebestcasescenario.com/forum/showthread.php?t=979&page=8) He's doing a head but it's the same principal that you need to use. Pics are better then my babbling.

See we do play with things other then just Pc's here! :)

CrazyBillyBob

[d_stilgar]

That is precisely what I was trying to explain before. Have the cast of her legs somehow suspended in the mold for the fin. Thanks for the help with the materials. I'm gonna have to talk to someone who really knows and has experience.