Foam for Pattern making

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#1

Hi everyone. I am making a new helmet from and existing design.I want to reduce the size a bit and other features and add some to other areas. here is my plan
I was going to cast a plug from a existing mold of the helmet i am modifying. I want to be able to work with this to make my changes.
I thought about plaster but i think it would be too heavy and messy and dusty and that amoung might crack.

any recommendations on some two part foams or some good easy to work with (ie can easliy sand and cut and form) casting resins?

any other ideas welcomed too.

Cheers
Tom

#2

Make a rough multi-piece fiberglass mold from the existing helmet. Using that mold, apply mold release, and pour expanding urethane foam into it.
You’ll then have a copy of the original to modify as you like.

#3

molds so i was thinkin AB poly urathane foam into mold and then you have it. just want to get good detail and have it sand and work easily.

#4

Be carefull with poly foam. Not many mold releases will release it, if any. I would coat your mold with wax+ seran wrap before pouring the foam.

If you use plaster, you can mix it with just about anything. I used PVA + Plaster + Chopped glass. It was hard as a rock and wont crack. Even used epoxy and plaster with no issues.

#5

Use finish care mold releases, with the 1000P wax. Its a helmet not sure i could get saren warp down without wrinkles. I like the idea about chopped fiberglass in plaster too.

How is that for sanding down and such? the plaster filled with glass and PVA