Fibreglass thickness


New Hunter
Hi there

I'm ready to start molding and casting a few clay sculpts of mine, and wondered what thickness of fibreglass sheet I'd need for helmet/chest armor. There seems to be several different thickness' around, and as I can only see them in internet pictures, I don't know which one would be best.

It'd be lovely if anyone with experience in this matter gave me a nudge :)

FIberglass is sold by weight. Whether it is matt, or cloth, it comes in oz/sq ft. For most costume helmets, two layers of 3/4 oz matt is good. One layer of 3/4 oz matt and one layer 10 oz cloth is better. I always finish a fiberglass lamination with a layer of cloth because someone is less likely to get a FG splinter.

Another thing I would like to pass along is that polyester resin smell terrible. In the event that you might not encase you head in something so pungent, I recommend using epoxy, or urethane resin in place of polyester.
Thanks for the info :)

One last thing, will the epoxy be as strong as the polyester resin if used? This would be really useful if true, as polyester resin is more dangerous than epoxy (Am I right or wrong there...)
The epoxy will be stronger than regular polyester resin. But the key to glassing is a tight lamination, meaning, make sure you work out your air bubbles. The less air entrapment the stronger your finished product will be.

You may also want to try slush molding with urathane resin. Depending on how you've molded your pieces this can be a quick, easy, odorless way of reproducing your sculpts. It is more expensive than fiberglassing though, and is the opinion of many not to be as durable.
Maybe you could post some pics of the molds so we could tell what method would suit you. Size and shape makes a big difference.
I've hit several snags with the epoxy resin plan, the first being the price and availability of it. If I put a Gel coat over the top of ployester resin would this reduce the odour? Although I highly doubt it as I suspect this is polyurethane as well(?). Alternatively, is there anything else that could be used as a surface protector?

Also, if I did bite the bullet and use epoxy, what would I do if I wanted to use gel coat to give it a smooth finish? Are epoxy resin and gel coat compatible?

Maybe you could post some pics of the molds so we could tell what method would suit you. Size and shape makes a big difference.

At present I'm still latexing most of the pieces, so haven't got any of the molds finished, but the biggest one will be a standard fett helmet sized 1 piece mold (at least, that's the plan) I'll try and throw up some pics of the WIP soonish
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