reinforcing my helmet

I saw a post about using fiberglass cloth with the resin to shore up the inside of a mask and it seems like its working pretty well. My question is, what if i put it on the outside as well?...
I saw a post the other night implying that fibreglass resin reacts badly with styrene. Is there anyone who has experience of this? (I was thinking of glassing the inside of my vacformed styrene helmet.)
If the styrene's thick enough, you shouldn't have a problem, just don't let the resin pool-up or become too thick anywhere. Thicker areas can build enough heat to soften and deform the plastic.
Eventually, the resin could attack and break-down the styrene, but most likely, the resin will be cured before that would happen. Once the resin is cured, it becomes stable. The reason resin attacks polystyrene is because the solvent in resin is styrene-monomer. I hope this helps clear things up better for you. :)
I used epoxy fiberglass to strengthen my styrene backplate.It worked like a charm,and it's rock solid.I had no problems with the heat warping the styrene,or any reaction from the epoxy.Hope this helps.

Thanks, Steve. That's reassuring. (I've since figured out that any warping problems will be insignificant compared to the problems of concealing the cost of the fibreglass resin from my wife!) ;)
a few corrections to make here from my experience in reinforcing.

Fiberglass Resin is what will eat away styrene and plastic slowly.

Casting resin is the solution. It will not eat away plastic.

So what I recommend for helmets is prewetting your fiberglass cloth with resin and laying it down very carefully.

If you have never done either glassing or resin casting I WOULD NOT recommend doing this since it can turn into a nightmare in that case !

Thanks for the advice, GM.

I'll try and source some casting resin and use it to stiffen the joins and the inside of the cheeks. I was wondering what brand of casting resin you recommended so I can look out for some here down under. Phil
tough one this is...its not like you could just get resin at your local store...You might try F/X solutions in Burbank, California...ask for W-65..its a white cast resin.

well you see that IS the problem. Every store for some damn reason has its own name for it...just ask for fast casting white resin.

that should do it.

"Alumalite" is usually way overpriced, but it's good stuff and you can usually find it at bigger hobby shops- one of my local ones even started carrying gallon buckets of their silicone! :)

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