Not a "Dumb Question" by any means. (A very
good question, actually.) If you will, this writer would like to offer a few thoughts on this subject based on his experience. Others, of course, might wish to weigh in.
"Resin" per se, most often refers to cast polyester resins: liquid (synthetic) resins mixed with a catalyst--and most often various colorants--poured into a mold and allowed to cure. There are many different forms of cast polyester resin, but this writer is not a chemist able to know, let alone explain, these differences. So for our purposes, and because there's little difference in every day use, let's just lump them all under the heading of "cast polyester."
Cast polyester is probably the most commonly used brush handle material today. It's readily available in rod form commercially and also as liquid "casting resins" which many artisans use to "roll their own." Cast polyester machines ("turns") easily with proper tools and techniques. It takes and holds fine detail well, polishes to a brilliant luster, and is durable in use. It's one drawback is that cast polyester tends to crack/break if dropped onto a hard surface like a tile floor. Otherwise, cast polyester is probably closest to the ideal brush making material.
Other commonly used brush handle materials include different woods, horn, various metals, acrylics, molded plastics, stone and metal composites, and most recently, Ebonite. Brushes have, of course, been made in other materials: early plastics like Bakelite and Catalan, (which have fallen out of use for very good reasons we won't go into), along with Amber, Ivory (from elephants and walruses), and many others.
Very briefly:
- Wood: depending on the species, wood is probably the easiest to machine. The largest challenge with wood, especially the rosewoods, is proper finishing. Wooden handles must be properly finished in order to stand up to the wet shaving environment. (A complex topic in and of itself, best left to another day. We might also include manufactured woods including those infused with epoxy or polyester resins under pressure.) Wooden handles are typically lighter in weight requiring the maker to add weight to the handle in order to achieve proper balance. Nevertheless, a properly-made wooden handle can be quite attractive and serviceable.
- Horn: Most typically from bovine species (Cows, Bulls, Water Buffalo, etc.) Horn can be made into quite attractive brush handles. However, unless properly dried, horn is subject to cracking ("checking") and delamination--problems widely discussed on the shaving forums. Properly dried horn is expensive and finding a reliable supplier can be a challenge, at least in North America.
- Metal: Brush handles can (and have been) machined from just about any metal imaginable: steel, aluminum, brass, bronze, silver, etc. Each has its own characteristics which, again, this writer lacks the expertise to discuss in detail. The most common disadvantage to metal handles is that unless the maker takes care, they will be unduly heavy.
- Acrylics: Comparatively hard transparent plastics sold under the trade names of Crylux, Plexiglas, Acrylite, Lucite, Perspex, and others can occasionally be found in brush handles. (Morris & Forndran, for example, made a few brushes from Lucite some years ago. This writer's limited experience with this material suggests that, due to its hardness, acylics are probably best machined on a metal (ideally CNC) lathe. This writer found acrylics difficult to polish and because of the way light refracts within the curves of a brush handle, found that even the smallest scratches are easily magnified, becoming quite distracting. (If you get the idea this writer doesn't care much for acrylics, you would be quite correct.)
- Molded Plastics: We use this term to refer to the molded plastic brush handles that occasionally turn up in some of the less expensive vintage brushes and also in the few contemporary Vulfix brushes this writer has handled.
- Stone/Metal Composites: These are "space-age" materials made from powdered or "atomized" metals--or metal combinations--or stones combined with appropriate adhesive binders. Such composites are easily machined on common wood lathes. They will take a certain amount of fine detail and, in the hands of the accomplished maker, can be made into quite striking brush and razor handles. Some metal composites (e.g., brass or bronze) will "age" to a nice patina. Such handles tend to be slightly heavier than cast polyester equivalents, but lighter than those machined from pure metal.
- Ebonite: Ebonite is a form of hard rubber that's been recently introduced to the wet shaving world--and become somewhat popular of late. It machines fairly easily, although due to its comparative softness, Ebonite doesn't lend itself to fine detail as well as metals or cast polyesters. Because it's a softer material, an Ebonite brush might be better able to withstanding a fall than (say) one in cast polyester. Finishing Ebonite does pose unique challenges as the maker must take additional time and exercise great care to remove all tool marks and "tear-out." (That nasty whitish "frizz" often found in between grooves.) For those reasons, Ebonite seems to best lend itself to handle patterns containing minimal detail. At least at present, Ebonite brushes tend to sell at a significant premium due to finishing time and raw material costs. Yet despite all that, when worked by an accomplished maker, an Ebonite handle can be quite stunning with its often vivid coloration and brilliant finish. This writer expects to see more Ebonite brushes become available as more major makers and at least one or two smaller ones introduce them.
Anyway, if there are any errors in the above; this writer hopes they will be quickly forgotten.
