Heya! By unceasing demand- Welcome to the FRP/Fiberglass 101 tutorial.
This tutorial will discuss safety, materials, and usage of Frp/ Fiberglass for your cosplay and other art projects. Any further questions, mail me at firstname.lastname@example.org
Polyester resins carry a distinct aroma. Yum. This is a Styrene Monomer. MEK, acetone, gasoline, etc.- many solvents have this tasty aroma. This should warn you that they're likely fireball prone and something you DON'T want to breathe, yeah?
Work in a WELL ventilated place. Many of these fumes are heavier than air, and will fall to the floor and collect. I use a fan in a window to draw the air/fumes out, and a FLOOR level fan to drive the heavier fumes up and out.
The first thing you should have is a respirator- not just a dust mask. A dust mask is great for particles of dust from grinding or sanding, but will not stop fumes. Keep your respirator bagged, as the filter/cartridges continue to absorb vapor and will be exhausted if left out, leaving you with an expensive 'dust mask'. Use citrus oils, cloves, etc., to check and see if your cartridges need replaced every so often- if you can smell lemon- it's time to replace the cartridges.
BTW... NO SMOKING. “Yoga, FIRE!” Even the fumes from a catalyzing resin will ignite acetone or solvent fumes! An odd odor- and then BOOM! Be careful.
Methyl Ethyl Ketone Peroxide/MEKP- this is the catalyst for polyester resins. If you get this on you you'll get a chemical burn. Remember Fight Club? “THIS, is a chemical burn.” Oh yeah- it can blind you, too. Respect, yo.
Wear rubber gloves whenever you deal with this stuff. The latex in most rubber gloves bothers my skin, so I use a plastic liner glove, and then a rubber outer glove. It's a pain, but it's better than the alternative.
Wear your safety glasses. Pretend you're Dexter.
Polyester is used in boat-building, fish-tank construction, etc., and of course- all our fav hobby and cosplay projects. They're easy to buy and use, and the results are dependable.
Polyesters are heat-setting resins. Heat alone will cause them to harden if left alone for months. Since you probably don't want to wait that long for your prop or project, you can add a catalyst (MEKP) to make it harden and cure very quickly. The catalyst causes heat, and the resin hardens. That's it in a nutshell. This is called polymerization. This is a one-way ticket- once it's set it's done.
You can adjust the time it takes to set up by varying the amount of MEKP/catalyst added to the resin. Also by using cold or heat. Polyester resins are catalyzed by volume- 6-8 drops of catalyst (MEKP) per ounce of resin= 20-25 min working time at 72 deg Fahrenheit. You'll lose some resin in your learning curve as it catalyzes too quickly and becomes a rapidly hardening blob in the cup. Cuss, and add less next time! So in the summer when temps are roasting- use less MEKP. Winter and cooler weather- it will take longer unless you add external heat, or more MEKP. Start with smaller amounts of catalyst until you have a feel for it. A test batch is a good idea, then you know exactly what to expect.
So it's all about the heat- either by added catalyst or ambient temps. Again- careful with the MEKP/catalyst- if you get it in your eyes, I hear braille is cool.
Many people also use EPOXY resins, which are very similar to Polyester resins, but the ratio of catalyst to resin is very specific- think cooking vs baking. In cooking you can play with the recipe and probably still be successful. Try this in baking and you're just washing out pans for fun. Epoxy is used commonly in marine applications. I don't use it, haven't any experience with it, and therefore say POLYESTER!
On to materials.
Fiberglass matte, cloth, or woven material is actually glass fibers. Dude. The resin and catalyst are mixed, and then brushed onto the cloth or matte glass. The resin then sets up and hardens, forming the glass into the shape it was laid. Some people have even used cotton t-shirts soaked in resin to form the base of those funky shaped audio speakers.
What you're probably looking to use are called chopped strand matte, and is what will come with most store-bought kits. There are many more options here from heavy construction 'wovens' for strength, to cloth and 'veil'- a very thin glass for uber-detail work. Usually all you need is the chopped strand matte.
I know, I know- so here's the skinny.
Take all your safety precautions- ventilation, glasses, gloves, respirator, and a clean work space. Spread out a plastic garbage bag or lay out a pieces of cardboard larger than the pieces of matte you intend to soak in resin. I use fountain drink cups to mix my resin. Always have a cup of acetone nearby for your brushes and other tools. Use the wooden stir sticks found in the paint dept. for mixing. Use a 'chip' brush to apply the resin to the matt. A chip brush is the standard natural bristle brush with wooden handles. A smaller brush is generally better for details.
Mix your resin and MEKP/catalyst, dip your brush into the resin or pour if you have a lot to dole out at once, and brush it over the matte until no white/dry fibers remain. Lift the piece of very malleable resin soaked glass, and apply it to your project. Use the brush to stipple or dab down the surface so it's smooth. Watch for air bubbles and 'chase' them out to the edges with the brush.
Don't forget to clean out your brushes with acetone when you're finished, or else your brushes are. Always remove any catalyzing resin left over in the cup AWAY from any acetone or solvent- remember? BOOM! The fumes from the catalyzing resin will ignite solvent fumes!
As the resin and glass begins to set it can be cut with a razor knife- again, careful Slash. Cut your excess away while it is still in this 'green' stage and you'll save yourself a lot of time and effort with power tools from saws to grinders.
This is the uber-basic procedure. Set up your project, catalyze resin and wet out your glass fibers, then apply, and cut/finish. After it's set you can apply bondo, gesso, paint, etc. for the finish you want. Oh, yeah- don't add polyester resin to your freshly sculpted foam or foam-core as it will nom nom nom your project and send you into tears. The alternative is to apply coat after coat of white glue to a foam project until it acts like a sealer over which the resin may be applied. This is how the Buster Sword was created.
These are the very basics. On request I'll put together more of these on advanced techniques, gelcoats, bodywork, and construction, but with this basic info and the examples from the Buster Cleveland page you can get started. Do your homework, plan out your build, and ask questions if you don't understand something. Be good to you.