What they're using for brushes at The Smithsonian
This article is used by permssion from the author, Donald Williams.
The article was first published on a refinisher's e-mail list, in December, 1999. It is included in its entirety. Neither Mr. Williams nor The Smithsonian Institute endorse any of our products, nor are they associated with us in any way. This article is presented for educational purposes only.
Don is a refinishing expert for Smithsonian Institute.
I am looking for some good brushes for shellac - I have a 3" badger brush, which is fine for flat horizontal surfaces, but would like a smaller brush for legs and turnings. Red sable? fitch? any suggestions would be appreciated. I need a source also. Thanks, I am enjoying all the info this groop has to offer - Dave
Don Williams writes:
You must be prescient. I was just musing yesterday that I might do a piece on brushes, and now you've provoked me. So Groop, what follows is now Dave's fault.
I've been brushing shellac for nearly thirty years (I only look like a teenager : ) I have settled on using nylon brushes only, as I find the resultant product superior. Period. One of the problems that people have in finishing with shellac is using the wrong brush. Most often they use something that performs no better than a whisk broom, and the results show it. The brush choice is even more critical if you are doing watercolor shellac work.
For brushing flat work, I find that a 1", 1 1/2", or 2" brush is all I need for even the largest piece of furniture. My personal selection of brushes includes mostly golden nylon flat water color brushes. They run $15-75 per brush. But, like I said, they provide superior results and don't go bad if you care for them properly (more about that later).
My collection includes Windsor Newton Series 580; Windsor Newton Leow & Connell "La Comeille" series. I'm guessing that in the small box that holds my good finishing and touch up brushes resides the better part of $1500. But they've earned their keep and then some.
The logic behind the selection is this: to brush shellac properly you need to thin it down to a 1-2 pound cut, which is essentially water-like in its viscosity. In addition, since ethanol is one of the more polar solvents, water being the most polar solvent, it makes perfect sense to use brushes designed for water.
Finally, the highly cross-linked nylon bristle is virtually impervious to the physical or chemical effects of the acohol: no matter how many years you use one, nor how many hours a job takes, the performance of the bristle doesn't change, again if the brush is properly cared for.
The same cannot be said for natural bristle brushes, which as a bundle of protein chains do change their mechanical properties with repeated exposures to alcohol (they become less stiff and bouncy) while their chemical constitution remains relatively unchanged. This is in part do to the ability of proteins to absorb and adsorb polar solvents. Think of what happens to hide glue on exposure to polar solvents. In the case of water, it becomes gelatinized or liquid, the addition of alcohol unzips some of the polymeric structure. (Or even think about your own hair in the swimming pool)
I have recently found another type of nylon brush at the paint store that seems to work admirably for architectural-scale projects. Rather than golden it is a pale wheat colored bristle sold under the brand name Corona Edge with DuPont Chinex bristles. It is a rather unusual brush in that its tip is not feathered like a lot of high end nylon brushes for latex coatings: it doesn't look like it has "split ends." However, like other good quality brushes, it has a price of about $15-20 for a 1" and progressing upward as size increases.
If you must use a natural bristle brush bristle, make sure that you sculpt the tip of it for best results. You do that by dipping it in a dilute solution of shellac and letting it harden into its natural shape, then you shape the hardened tip of it with either files or sandpaper so that you get an even, smooth, flawless taper to the point.
So far the only natural bristle brush that provided anything like a decent result has been an oval sash painter's brush (I bought a half dozen about twenty years ago) from Johnson Paint in Boston.
For curved or carved surfaces, I have recently discovered the remarkable Loew & Cornell "Filbert Mop" which has a flat ferrule but a rounded tip. My success with it has been nothing short of astounding. I debuted it at last year's workshop and people were literally ooohing and ahhhing. It's that good. Run, do not walk, to the nearest art supply store and get one.
For touch up and inpainting I stick to the same brands of nylon brushes, making sure to have a good variety of sizes. For the best results in fine touch up on transparent finished surfaces, I use a type of brush called a "Rigger" which is inordinately long for its diameter. It is 2 or 3 times longer than typical round brushes, so I get an excellent load on to and flow off of the brush. However, because of their length and surface area, they need to be cleaned frequently during a project. For larger transparent work or painted surfaces a typical nylon round water color brush works fine.
The only viable alternative to nylon I've found for touch up is to use a Kolinsky sable watercolor brush, which does indeed provide a superior result. But if you want to use them, make sure to go to the bank before you go shopping. Unlike other sable brushes, Kolinskys are taken whole from the very tip of the sable's tail (thus a limit of one brush per rodent), and they naturally form a round, perfectly tapered tip that performs flawlessly. But be prepared to part with $75 for even a little one, and most are in the $100+ range for the real thing. If you see one advertised for markedly less, it may not be what it claims (I'm shocked, SHOCKED!) Other natural bristle brushes simply wimp out.
As for care and feeding of brushes, when I clean them I do not clean them 100% clean in alcohol, but rather to only about 95% clean. That way, after they are "cleaned" I gently form them into the proper shape and let them dry slightly stiff so they retain their shape perfectly. One of the bad things about nylon brush bristles is that if they get bent or warped you might as well throw them out or let the kids use them for their nails, and cheap brushes lose their shape after only a couple of uses. One way to tell is if the tip forms cleanly or is separated when wet. If the tip separates more than a millimeter, toss the brush.
I have taught this approach to brushes for shellac to tons of students, and the feedback I get is unanimously positive. For more on brushing technique itself, check out my FWW article from the Mesozoic Era. (Fortunately or unfortunately for you, FWW said "No thanks, our readers just aren't interested" in the dozen other finishing article proposals I sent them)
PS -- I teach a shellac workshop every year at Olde Mill Cabinet Shop in York PA. About 75% of the time is spent on brush work. Date for next year not set. Their catalog even carries (or at least used to) many of these brushes as "Don's Shellac Brushes" but you can get them at any decent art store.
© 1999 Donald Williams (used by permission)