Yuppers, like Fuffuloo said, always use a respirator (not a dust mask). It may cost as much as your resin, but it'll prevent you from having related medical problems down the road. That resin is baaaad stuff. Also, I think respirators look pretty cool.
Ok, I started writing individual responses to your fiberglassing questions, but I realized it would probably sound vague without giving some timeline or list of steps. So, I decided it would be better to post this in depth tutorial I wrote up a while ago. I hope in the info below you'll find lots of things you knew how to do, then the few things you weren't sure about, and then finally how they relate to each other.
(Hehe I've been up since 6am so if anything is confusing let me know lol)
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Step 1, preparing the exterior (No Fiberglass Cloth until Step 2, we are working strictly with the resin and hardener)
<ul>[*]Mix a batch of resin and hardener (I mixed 2oz. for mine). and 'paint' a layer of it on the exterior of your piece. You will have
approximately 20mins to work with your resin (depending on temp) before it starts turning into globules and curing.[*]Allow it to cure (usually around 2 hours, but read your packaging for specific rates).[/list]It will look something like this after 1 coat:
<ul>[*]Mix another batch and apply a second layer of resin to the exterior. [*]Allow the 2nd layer to cure.[*]If after the recommended time your piece still has a little tack to it, you can put some baby powder on it.[*]It'll still be rather flimsy but will be stiff enough to hold it's shape under the weight of cloth.[/list]
Step 2, strengthening the interior
<ul>[*]Fiberglass cloth will commonly come in rolls or 8sqft. So, begin to cut your fiberglass into strips. The idea is to overlap the cloth and contour to the folds of each piece.[*]Using spray adhesive, gently adhere your strips of cloth to the piece. Use just enough spray adhesive to hold it in place while you work with the resin. The spray is not meant to make your armor strong or keep the cloth on there permanently.[*]Mix a batch of resin and hardener.[*]Begin to paint the mix onto the cloth. You want the resin to go all the way through, so you will need to apply pressure with a brush or your gloved hands to get the resin to soak through the cloth and onto the piece. [*]Smooth out air bubbles with a roller or your gloved hands (i think fingers work well since most surfaces are pretty curvy).[*]Allow to cure.[/list]Here is the inside of a piece after the fiberglass has cured:
Here is the outside of the piece:
(I held this up for the picture but it's a good idea to wear gloves when handling, because the stray strands are pretty spiky)
At this point, you could add more layers of fiberglass or continue by sanding, filling, priming, painting, etc.
After a coat of primer:
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I'll actually bondo, sand, and re-primer that piece but hopefully that gives ya the skinny on fiberglassing

-Vex