Best Mold Making Material

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#1

As a lot of you probably know I am going to build a nose cone for a formula team on campus and I was wondering what the best material for one off mold use was. Things we don’t have are lots of money or specialized tooling. Things we do have are manpower and a large group of intelligent but somewhat inexperienced students.

Foam seems to be a good choice but I was wondering what type is the best for the price and what sealers would need to be used.
However I am making this thread to get any suggestions.
Thanks in advance!

#2

the pink insulation foam sold at home depot works really well.we have built a few full bodies with it.have you seen the west wx10?that whole body was built from pink foam.some of the flats where 1/4 masonite.we roughed the foam to shape less an 1/8 of an inch of final size.then painted the foam with cheap latex home paint.then its safe to cover with body filler.fill.sand.fill tell you get your shape the way you want it.you can wet sand the body filler and pull molds from that or shoot it with featherfill polyester primer.the primer helps to see flaws that dont show up on the different shades of body filler.if you use the primer then wet sand that up to 600 or so.then for the molds we did tooling gel coat and polyester resin.we used a 3/4 ounce chop strand for the first few plies.then switched to 1.5 ounce to bulk it up to a thickness of 3/8 inch.this method works well on race car bodies.its cheap.just takes time.

#3

So this foam is the best, I’m also looking and would like to know the best for what I’m doing. I am building a hood scoop, similar to the Subaru STI hood scoop.

Just wondering to to see what the best material would be for the mold. Im using carbon prepreg with an epoxy resin.

#4

if you are doing smaller parts.i would use the shaping foam.i bought some from fiberglass supply.its yellow in color.it shapes very easy.you can use body filler right over the foam.its a bit pricey though.thats why its not used on full bodies.for doing a small scoop this stuff would be the best.if you are not making a mold after you shape the foam.they also sell a sealer that will seal the pores of the foam.you can then lay up your part right over that.

#5

the foam is called (last a foam)looks like you would want the 6lb density.it comes in a few thicknesses.

#6

Yes I use Last-a-foam for pattern making quite a bit. One advantage is that bondo and acetone doesn’t attack it. I get it from AVT in Indianapolis.

#7

it shapes really nice too.