Reinforcing plexiglass armor???


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I'm building a Halo Master Chief Mark VI suit and I will be vacuum forming thin plexiglas for the armor pieces. It's a pretty flexible and I'm going to need to reinforce it with something on the inside. I don't have the kind of cash to purchase Smooth Cast, so I was hoping you guys could give me some affordable suggestions.

Please and Thank You!
Why plexiglass? I would use ABS or HIPS for forming. Unless you were just talking about the brand name? Fiberglass resin with fiberglass mat is the best choice. Very affordable and it can be found everywhere.
From what I read in the 405th, the thin Plexiglas sheets (it is actually plexiglas material this time, not just the name of the brand) I purchased have worked for many people who built Halo armor. But the only problem was, they all said it's a safe idea to reinforce it... just in case. I've seen how durable foam is; you can drop it and kick your pieces around without having to worry if it'll be okay or not.
Psicorp7 isn't fiberglass a bit messy?
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Fiberglass is extremely messy.. I only work with fiberglass and am currently trying to work a bit with foam. I also built my own vacuform table and have done quite well with it but it has it's own place in armor fabrication. Bondo will bond to plexi glass but if you deside to go that way use the Bondo with fiberglass strand in it and if you use thin coats it would be much less messy. The only other thing I've thought of trying was to use Liquid Nails by running a wide bead around the borders. Liquid Nails bonds to Plexi glass as well and I would think it would help keep it more rigid but like I said, I haven't tried it yet. Feel free if you want to try it just let us knoe if it works.. Best of luck.:)
The reason I say ABS is that is what Stormtrooper armor is made of and it can take quite a pounding without any reinforcing. My set has seen dozens of troops and is just fine without reinforcing. Using ABS or HIPS will save you a ton of steps, money and hassle down the road. Having a material that can flex without breaking is more important than making a fragile material extra rigid and heavier so it will not crack. I only use plexi if I need to make clear visor or part.
I'll try getting my hands on ABS, it does seem like the better option. At this point I don't have too much of a choice though since I bought a lot of thin Plexiglas which was on a great sale (It's not really a waste if it doesn't vacuum form well because I can just use them for visors and whatnot later).

My concern about fiberglass is that since it does have an exothermic reaction, i think it MIGHT deform my plexiglass molds. I'm crossing my fingers and hoping that it won't, so that I can use all these plexiglas sheets now instead of watiting a week or so to pay for those ABS sheets to ship here and start vacuum forming all over again.

I'll post a picture of the molds before and after the fiberglass reinforcement is applied. wish me luck.
I guess my questions are:
what are your vacuforn molds made with?
what is your vacuforming capacity? Are you using a shop vac and table, or a machine with vacuum pump and reserve?

these will determine your material choice. The standard goto material for vacuforming is HIPS, as it is most forgiving. Both Plexi, and ABS require more heat control and vacuum to form.
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