I’ve been working with 2-part epoxy for quite a few years now. If memory serves, I think my first experience was the cylinder head repair on my 327 Chevy racing motor when I was 17 years old. My Dad showed me how to use JB Weld to fill a crack between two valve seats, and that repair served me well for many years.
After that it was miscellaneous repairs here and there with those little double-plunger tubes of Devcon, LocTite, etc., that you get from the local home improvement store. You know the kind. 5, 10, 30 minute cure times depending on how fast or how strong you need it to be. Squirt some on cardboard and mix it up with a toothpick. I’ve also played around with those sticks of putty that look like a big Tootsie Roll with mixed results. More recently, in 2008 I build my first laminated wood speargun thanks to the help of my good buddy Phil Herranen. Phil started out shaping and glassing custom surfboards, and later on got into building custom spearguns. If there’s anything you need to know about fiberglass, composite weaves, wood, or epoxy, Phil’s your man. He also does HVAC and sheet metal fabrication on high-end custom homes in the Santa Cruz area if you’re in the market.
I don’t want to bore you with all the science involved, but epoxy is basically a chemical reaction between two liquids; a resin and a catalyst. Mixed together in the proper ratios, molecular bonds begin to form causing the liquid to become a solid. I tend to paraphrase just to simplify, but that’s about as much as you need to know to start using the stuff. I’ve been using West System for the majority of my boat projects just because I can get it on the cheap from Port Supply, and I’ve been mixing some serious quantity recently. 105 resin and either 205 fast or 206 slow hardener as the catalyst. For filling and fairing there’s any number of “fillers” I use for thickening to various consistencies, and for that, I pretty much eyeball the proper amount of powder until I get the thickness I’m looking for.
Recently, my sailing buddy and dock neighbor Kevin on S/V Toucan used some of that new fangled West System Six10 to do some small repairs on his boat. It comes pre-thickened to a ketchup-like consistency with each part separated inside of a nifty little tube that fits a standard caulking gun. The tip that screws on the tube does the mixing of the resin and hardener as it’s dispensed. It couldn’t be simpler or more convenient. With somewhere in the neighborhood of 300 screw holes I needed to fill in the cockpit, rather than mix 105/206 with 403 thickener and squirt each hole with a tiny little 2cc syringe, I figured I’d give it a try. Needless to say I’m pretty impressed.
At $25 bucks a tube and $2 each for the mixing tips (retail markup on this stuff insane), you certainly don’t want to mess around. Once you crack it open and start dispensing, you have about 45 minutes of working time before it kicks off and hardens up in the tip, thus rendering it completely useless. If you don’t use the whole tube before the tip solidifies you can install another mixing tip and keep working, or when you’re finished you can cap off the tube and use the rest another day. Either way the tip is shot, so definitely buy some spares. One tube wasn’t quite enough to finish all the holes I needed to fill in the cockpit, so I still had to resort to mixing A & B, plus powdered thickener for the last few. But I can say that with our Port Supply discount I would certainly consider bringing a half dozen or so tubes and about 20 mixing tips along with us when we finally cast off the dock lines once and for all.