The best resins for wrapped handles are quality grade commercial resins. Hobby grade from the hardware store are just asking for sticky handles. Use West System or System Three resin and you will be much happier. For impregnating ito and cord wrap, they excel, IMHO. System Three clear coat is excellent. Regular West system 105 resin and 206 slow cure hardener is also good. The clear coat comes in a small bottle set which meets the small makers needs better than buying quart cans of West System. The West system slow cure 206 hardener allows for careful application without rushing and drips.
Whichever resin you use, the first thing to do is mix it well, and as john pointed out, don't work from the mixing pot. Use two cups...one to mix and one to work from. I use the 2oz. take-out cups used for sauces, and they are perfect for mixing knife handle batches of epoxy. Many knife suppliers sell them, and the Big-box stores have them by the case. A case will last you and a dozen makes a lifetime, but they are pretty cheap by the case.
Once mixed, application is where people go wrong the most. It only takes a small amount of resin to impregnate the fibers. I use a disposable flux brush from HF and apply the resin sparingly. You want it to wick into the wrap, but not coat it. Brush on a very thin coating, turning the knife as you coat. It should soak in and disappear. If the handle gets a "wet" look, it has way too much resin. Keep a piece of cotton cloth handy, and when you think the handle is just right as to the amount of resin, wrap it in the cloth and squeeze hard. Remove ( and discard) the cloth and let the handle dry. I turn it every few minutes, looking for any drips ( which I blot up with cotton cloth) as the resin sets. Once the work pot of resin is set, I let the handle cure for a day or two. The final result is a wrap that looks like plain cord or ito, but is rock hard. I cringe when I see some of the resin coated handles in photos that are completely coated with a layer of "plastic" looking resin.
