Handle-shaping without electricity
I've made and shaped something like twenty fly rod grips the old-fashioned way. After the epoxy between the single rings of the rubber band-compressed handle has dried, I cover the adjoining reel seat and the blank above the handle with several wraps of hasking tape, for protection against slips. Then I sit with the butt section in my lap. I start with a coarse wood file (which cuts away any protruding epoxy in a stroke or two) and rasp away, turning the blank after every three strokes. I work free-form, stopping frequently to test the feel of the emerging grip. (You can remove more cork, but it's hard to put it back.) You can shape any style of grip you want, including those that include "burl" (compressed wood chip) rings and custom indentations for thumbs or palm pads.
When you've got it near the proper size, switch to sandpaper wrapped around a paperback novel; first coarse, then finer paper. I can't match the polished-woodlike finish of commercial grips, but what I end up with is smooth, good-looking, and comfortable.
I also use preformed grips. I have no preference, but some of my favorite rods have manually shaped grips as described above.