looking for a expanding foam that is sculptable

[sabanknight]

Me and my brother are beginning to work on a Commissar and Techpriest costume duo, from the warhammer 40k universe. Still working on paper, but where we are hitting a wall so far is the techpriest backpack. We have supplies for the servo-arm, but the backpack/powerplant -not unsimmilar from the space marine powerplant- is where we are unsure. We currently are planning on making a wire skeleton for it and filling it with an expanding foam. Only problem is we do not know of a product that we can use that is economical to fill a backpack that is 3.5' by 2', can withstand wear and tear, and is sculpt-able with sanders and dremels. anyone have any ideas or products to help us out?

 

[DaddyfromNaboo]

Go the usual route, get an epoxy expanding foam (2K instead of 1K!) and then carve it into basic shape, then cover it in bondo or glass and then sand the heck out of it If you want to save on foam, then you might want to build a box beneath the backpack that gives you some dead space/empty volume.

 

[modelnutz]

2 options come to mind.

1) Smooth0on's Foam -It line....the 10 lb. density foam is pretty tough stuff...cuts and sands real well too. It can be coated with fiberglass/Polyester resin/Bondo without damage

2) get to an outdoor sign shop and see if you can score some urethane foam board. Very similar to the Smooth-On stuff...perhaps a bit denser

 

[Wesman]

What are you sculpting? Large trees or rocks? 2# urethane foam. Something with detail? 4-6# urethane foam. CNC or machining? 6-10# urethane foam. Look it up on line as there are several suppliers other than effects companies that sell it for stuff like floatation chambers in boats and insulation.

 

[RevMarx]

I just used some Smooth-On "Foam It 5" (5 pound) to round out the ends of a two liter bottle. It was shaped with a hand rasp. Not difficult at all. It will still need bondo though to make it smooth. I would say it's too expensive to fill that much space with (for me at least), so I would agree with ManfromNaboo and suggest filling the center of the void with something, like an empty box. I sometimes use ping pong balls (that I bought cheap at a discount store) or empty plastic Easter eggs (great time of year to get them too) to take up space in in the center of larger plaster or foam projects like that.

-Rev. Marx