Making fiberglass mold?

Question

how do you make a mold for fiberglass and what are i thing i need to make one

Answer 1

Simplest approach is a wood framework with "Bondo" (an auto body filler), to shape it out.

The Bondo uses a hardening agent (I'd suggest the colored agent, to help with mixing)

As to what tools you'd need, that really depends on what kind of mold you're making..... saws, shapers, etc for the wood framework, and mixing spreading tools for the Bondo.  Once it has set, then you can go back and sand it with a fine grit paper.

To actually start producing parts, you'd need some mold release, and if this is a large mold, perhaps a fiberglass chop gun.

If you are using acrylic sheets, then you'll need a heat booth, and vacuum lines, to help pull the acrylic into the mold shape.

(There would actually be one mold for the acrylic, to shape it, and then fiberglass is chop/sprayed to the backside)

Gelcoat is used to provide color to the mold, and then the fiberglass is chopped/sprayed over it, to produce things like the booths you'd sit on at McDonald's, or Burger King.  Once the fiberglass has set, you pop it out of the mold, and the color is bonded to the fiberglass.

Most large molds require some structural reinforcement too...wood or steel that you would add to the fiberglass.  For example, if you ever looked under one of those booth seats at a fast food shop, you'd see a wood frame under the fiberglass.  Some spa manufacturers will reinforce their shells with brackets, etc.... these are usually covered over with the fiberglass, or at least anchored to the fiberglass, before the part is pulled from the mold.

Oh yes, there's usually some trim cutting involved too...which would require a die grinder.  VERY messy work.

We'd really need more details from you, to give more specific advice.

Have Fun

Answer 2

To learn it RIGHT - would mean I'd have to type a book for you.

First thing you should do is watch this video on youtube:

http://www.youtube.com/watch?v=DEa5_WHQZ...

Then watch other videos from this dude. Then read a book or get on a fiberglass forum like Werksberg http://www.compositeforum.werksberg.com/

Then try it out on some cheap stuff --- using cheap gel and fiberglass materials. Don't skimp on the PVA (and/or wax) or you'll never get the mold off.

You WILL mess up - but don't worry. It took me years to get it perfect.

I order all my stuff from www.fiberglasssupply.com. You can get your resin, catalyst, fiberglass, catalyst dispenser, chip brushes, PVA, gel coat, mould-release wedges, and anything else you need from them. Ask them for "end of roll specials" on the chopped strand mat (CSM). I got an 11 inch wide by 50 yard roll of CSM for $12.

To "tint" the gelcoat, you need the specific tinting stuff. You can buy gelcoat that is already colored, but the most common is white. Some tooling gelcoats are harder and made to build your moulds. Some of those are orange, black, or other colors.  I wouldn't try to tint your gelcoat while you are learning. You can always scuff and paint your finished part.