Any tips for molds

tubachris85x

Well-Known Hunter
Hey, Im in the same boat as you, but I think one way of doing it is making the sculpt out of some hard clay, make a plaster mould of it, and then using that plaster mould, cast the vacu-form mould out of resin or some hard material of the sort...

-tubachris
 

tubachris85x

Well-Known Hunter
There are diagrams I found online that have all the pieces minus the helmet, with all the measurements, Im using that for the molds I will help make for the group Im gonna be working with soon. Fortunatly, one of them already has a vacu-form machine...

-tubachris
 

CombatBaby

Well-Known Hunter
mdf is cheap and easy to make molds out of. I use it to make molds for guns and things like stormtrooper/biker scout armor.

otherwise sculpting out of clay works like a charm. Depending on what material you use, making a negative to make another (harder) positive may not be necessary.

this should be very helpful http://www.tk560.com/stormtrooper.html

-=QuinN!
 

tubachris85x

Well-Known Hunter
I always thought about using MDF for making the molds, but I dont have any wood working tools for it.

-tubachris
 

drcrash

Hunter
Consider sculpting in pink (Owens Corning) or blue (Dow Styrofoam(TM)) insulation foam, making an intermediate plaster waste mold, and casting a sturdy buck in that.

Don't vacuum form directly over pink or blue foam. You won't crush it, but you'll scrunch any protrusions stretching plastic across it.

There's a couple of relevant threads about this going on over at tk560.com.

Here's one:

http://www.tk560.com/phpBB2/viewtopic.php?t=418

There's another thread about hot wire cutters & jigs for sculpting foam, in the vacuum forming forum.
 

tubachris85x

Well-Known Hunter
Consider sculpting in pink (Owens Corning) or blue (Dow Styrofoam(TM)) insulation foam, making an intermediate plaster waste mold, and casting a sturdy buck in that.

Don't vacuum form directly over pink or blue foam. You won't crush it, but you'll scrunch any protrusions stretching plastic across it.

There's a couple of relevant threads about this going on over at tk560.com.

Here's one:

http://www.tk560.com/phpBB2/viewtopic.php?t=418

There's another thread about hot wire cutters & jigs for sculpting foam, in the vacuum forming forum.


What would I use to cast the buck out of after making the waste mold from plaster? Really dense resin or some kind of liquid cement hardner?


-tubachris
 

drcrash

Hunter
What would I use to cast the buck out of after making the waste mold from plaster? Really dense resin or some kind of liquid cement hardner?
-tubachris
For short run stuff, or an intermediate mold I wouldn't form directly over more than a few times, I might use something like water putty or gypsum cement, with drywall tape reinforcement.

For something really durable, I'd probably go with a resin impression coat, and lay up some fiberglass of some sort under that. Maybe just a healthy layer of Bondo-Glass. (Which is not like regular Bondo. It's not easy to sand, and it's much stronger, because it's filled with glass fibers instead of little microbubbles.)

If I still wanted to be able to sand and modify it easily, at the expense of making it somewhat less durable, I might start with a layer of regular Bondo. Then, deeper than I'd ever want to sand away, a healthy layer of Bondo-Glass for overall strength.

BTW, don't trust me on this. This resin/glass stuff is all still on my to-do list, not something I've actually done. (Today I'm experimenting with hot wire cutters for the foam part... I'll get there eventually.) I have done plaster waste molds and reinforced water putty casts, but not fiberglass.

Paul
 

Tim Allen

Well-Known Hunter
You want the best way to learn to do molds. Go to the " YouTube" web site and type in Resin Molds, Mold making, or some other variation of that. They have tons upon tons of how to videos showing you the material needed to make accurate and structural sound molds.
 

drcrash

Hunter
I dunno, I was using an electric saw (portable jigsaw) when I was 12. I don't see vacuum forming as being that dangerous. You might get a painful burn, but probably nothing disfiguring or even permanent, and you probably won't cut off any appendages. The most dangerous part is trimming the plastic with Sharp Things.

Whether it's something a 12-year-old ought to be doing depends a whole lot on the 12-year-old.
 

GrottyFurball

Active Hunter
Umm you have to put plastic in your oven. I think thats a bit more dangerous than using a jigsaw. The only people I've seen get hurt with a jigsaw were really stupid. It's practiaccly impossible to hurt yourself with one unless you're trying to.
 

GrottyFurball

Active Hunter
Also, any vacuum forming molds have to taper outward towars the bottom and have no "lips" for the plastic to get caught on. The most tricky part of it is designing you molds to get around this issue.
 
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