Common term, is wire nut. Various styles, and brands and names. Should work. Try using upholstery thread, it is thinner, and strong, and makes for a neater wrap. Not bad at all though for the materials you have at hand. Keep at it, you will start fine tuning. It is time consuming, but like a good bow, take your time, it will come out fine. When you use the natural shafts, boo, shoots, etc. you want the thicker end for the point, and the thinner end for the nock. You can use an open end wrench for a measuring tool, to size your shafts when you go to cut them. for the boo, cut the second growth shoots, those with no culms, or dry, and dead culms. Other wise they will shrink, and wrinkle. Also no strength. Bundle them in lots of twelve or so, and wrap them well, and tightly, and put them in your attic or some dry warm place for a couple months or so, and take them out and look at them, if they are not dry, put them back. You can leave them there for more than a couple of months, if you want. But check them periodically for bug holes. Little $#$#@$!! beetles, like pine borers will bore a hole in them, and eat them from the inside out, and you will notice little holes, in the side, and real fine saw dust. they are ruined then. PUT THEM IN THE FIRE. You can put shafts in the sun, in your car, etc. and they will turn a nice yellow, to tan color. You straighten them, by heating them, but not too hot, or in one spot too long, or you will burn them. I use a Harbor Freight heat gun. Just keep moving the gun, and rotating the shaft. You can make a simple arrow straightener, out of a board, with a hole in it, or a limb, with a notch in it. A 2 X 4 cut with a half moon hump in the middle, and three or four inch sides like handles on each side of the hump. Then you can heat the shaft, and place the heated area on the hump and hold the shaft with some pressure on the hump, till it has cooled, and then look down the shaft, to see if the straightness has improved, and move on the the next spot that needs straightening, and leave the node section for last. Then when it is straight, you can sand the nodes, smooth, and even with the shaft. Some people recommend boring out the nodes. I do not! It weakens the arrow. the nodes are the weak spots of a boo shaft You can straighten the sections between the nodes, first, and then sand the nodes down, smooth, and you can use a spray can of lacquer to coat the entire shaft. They will be very nice looking, and the sanded nodes will be water proof. You can put a small dowel down in either end, and use it to hang the shaft, and spray it, and let it dry, then you can use four 0 steel wool to lightly sand it. You may have to put a couple of coats on it. You can sand the entire shaft if you want, but then seal it with lacquer. Some people use a pvc pipe, and put the lacquer in it, and dip the shaft in the lacquer, and then hang the shaft to dry. Which ever method works for you is the one to use. I use the spray can. There are many how to sections on here, and You Tube. Check them out, and you can see how other people do it. Nice first arrow. Now make a dozen more. Let us know how they fly.
Wayne