Thread: Working with Foam

You are the grandmaster of this stuff.

Do you think latex rubber would also work to make the mold? The stuff I've used is about the same consistency as milk, which I would think would give you a great smooth finish around the stock with no bubbles. Not sure about any seepage under the stock though...

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I think latex has one major drawback which is that it only dries in thin sections which means you'd need some sort of mother mold to hold it in shape. That means lots more draft and you kind of lose the flexibility that silicone gives you. That isn't to say it cant be done or isn't done. I just think that for this type of thing you can't beat silicone.

I went to the store and to my surprise they had dyes for the Alumilite! So i picked up a bottle of black and thought i'd give it a try. The results are pretty good if you just want a nice ABS-level black.


I had a little resin left over so i couldn't resist....

It's amazing to note the level of detail this stuff picks up. If your foam model were finished glossy, you would never have to finish your poured parts! they'd all come out the exact same way!

love peace and grease!

Amazing work on both the mold and this thread, GoHybrid. Your prose and completeness makes this a process that anyone should be able to follow and achieve similar results.

I'm jealous (but not jealous enough to prevent me from trying this myself when I get around to building a bezel, of course)!

Mods, make this a sticky!

I got the black bezel installed last night! I think it matches well enough that i can leave well enough alone. Sweet!





Parksgm, thanks for the props!

i think it cost something like $450 for a 4x8x4" board including shipping... but I do alot of prototyping and model making so it was something of an investment.

Freeman sells partial boards in lower thicknesses that you can get into for well under $100 i would think. If you check out the different types of RenShape on their website you can request a quote for a certain quantity.

this is a really cool method of fabricating parts from nothing... thanks for showing this... I got a question... when you do that bombs away pour... do you have to pour the whole mould in one shot, or can it be done in several pours?... I guess with something the volume of yours it's easy to just do it one pour, but what about larger parts? if a few mix & pours are done sucessively, would that work?

The pot life on this silicone is 1.5-2.5 hours so if you can't fill your mold in that amount of time then there's a better way to create that mold than a simple mass casting. Check out this video on glove molding for a process that might lend itself better to doing large parts.

It only took about 5-10 minutes, if that, to fill my mold which was about 40 cubic inches. If it's the speed of the pouring you're concerned about, it goes quite a bit faster than it looks. The other alternative, vacuum degassing, obviates the need for the bombs away method so you can pour deaired silicone at a much higher rate.

I'm told silicone will stick to itself in the absence of a proper mold release so i suppose if you wanted to modify an existing mold you could pour on top of that... Does that answer your question?