Can anyone find out if Craft Foam can be used in "Lost Wax" casting?

[RyanL]

I found it once before starting my project, but can not find it again. I'm wanting to make sure it will burn out of the investment without leaving a bunch of debris.

Thanks for the help. :)

[Ryan Mcdermott]

I'll tell you that you probably want to check the msds to see what
toxic chemicals will be released when you burn the foam off.

But *you* have to check it.

Google lost foam casting.

-Gibson

[Brian Aday]

Which type of craft foam? The green stuff used in floral arrangement's? Most of the casting I have seen is done with white Styrofoam or the blue foam used in insulation. There is no way around the toxicity, they both put off some nasty gas. A respirator should be used. 

IIRC when using foam as a pattern for investment casting you wash the mold out with acetone to melt the foam. You may want to try that on what you have to see if it works. 

[Ryan L.]

I'm using the EVA craft foam, like the sheets you get at Michael's. I did a search on it and found that despite the smell it is rather harmless. EVA is even used in cigarette paper to make "fire safe" cigarettes.

[John Norman]

We've done it at 23b. You take the foam pattern (with a foam sprue glued on using Elmer's white glue) and bury it in plain old sand with the sprue exposed. It does not need to be sticky foundry sand, at least in my experience. In fact, I've heard that regular sand is better, as the spaces between the grains allow the gases from the burning foam to escape better.

You pour your hot Aluminum (or whatever) directly onto the exposed foam sprue and it automagically vaporizes away the pattern as it fills the mold. I'm sure it releases Chlorine and other bad stuff. Definitely do it outside.

Arclight

[Ryan L.]

Thanks for the help. I think I'll have no problem with it, though may need to do a cooling period after burnout and do a cleansing step to remove any ash.

Should be fun. :)