The biggest tip I have is - "Don't dip the handle!"
Here are a couple tutorials I did a while back:
Tutorial 1) Clamp the blade in a big spring clamp or woodworking clamp so you can get to the handle from all sides easily ( A parallel jaw wood clamp works really well). If you are going to make a lot of these, you can make a rotating wrapping stand like the ones used to do sword handles.
Wrap it, and check everything. If it isn't looking right, wrap it again....it won't look any better after the resin gets hard.
When all is looking right, give the handle a flame off with a small flame. This gets rid of the fuzz and loose filaments. Brush it off gently with a soft brush to remove any ash.
Look it over closely for places where strands overlap or have a bad twist. Adjust them if needed. Don't accept a sloppy job just because it will be a necker or camp knife. Every knife deserves a good handle. Hemp is cheap, re-do it if you are not pleased with what you see.
What is really important is to use a thin and clear resin. I like System Three Clear Coat.
Use a small flux brush and apply the epoxy very sparingly. It will soak in almost immediately. Done just right, it doesn't look any different. You don't want it to look wet at all. After you brush in the small amount needed, take a lint free cotton cloth and squeeze the handle. This will remove any excess. Set the mixing cup of extra resin aside to check as it cures. Set the spring clamp so the knife is sticking out horizontal off the edge of the table ( It's a good idea to put some papers on the floor). Let it sit for a few minutes, wipe off any drips or pooling, and turn over to reverse sides. Rotate every few minutes until the excess resin in the cup starts to gel. Once it gets thicker, don't mess with the handle any more. Let it cure for a day or two, and it should be rock solid.
Tutorial 2) 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.
