The Best Way to Clean a Shellac Brush
I’m a big fan of shellac as a finish, for many reasons. It’s a very forgiving finish. It’s a natural material and the solvent (alcohol) is also safe and natural. It dries fast, allowing me to apply multiple coats in a single day. It is capable of just about any desired sheen. It can be used over or under just about any other finish. It can be used to block odors or stains in a board. It’s durable enough for any type of interior woodwork, and it’s easily repairable if it does get damaged. Plus, when stored in a well sealed container in flake form, it has an almost indefinite shelf-life.
The only thing that can be a minor inconvenience with a solvent based finish like shellac is getting the brushes used to apply it thoroughly clean when you’re done. However, there is a very simple solution to this little conundrum – don’t clean the brushes.
Rather than spending a bunch of time and wasting a bunch of solvent cleaning out the finish left in the brush when I’m done applying, I simply put the brush aside and let the finish harden in the brush. This not only allows me to avoid cleaning the brushes, but the hardened finish also serves to protect the delicate bristles of the natural hair brushes that I like to use. Since shellac will redissolve in its solvent, letting the finish harden in the brush has zero detrimental effects on the brush.
The next time that I need to use one of my shellac brushes, it’s a simple matter of giving the bristles a soak in alcohol prior to use to soften the brush back up and make it ready for use. It typically takes about 20-30 minutes of soaking for the brush to be as good as new. I will usually use this time to do the finishing prep work, like masking off any areas that I might need to mask, protecting my workbench surface with some paper, cardboard, or a drop cloth, if necessary, cleaning the dust from the piece that is being finished, etc. By the time I have the prep work done, the brush is usually soft and ready to go.
When the brush is ready to go, I remove it from the alcohol and blot the excess solvent out of the brush into a few clean paper towels. At this point, the bristles should be as soft and supple as they were when the brush was new.
By the way, this will also work with traditional solvent based lacquer. Since this type of lacquer can be redissolved in lacquer thinner, you can let solvent based lacquer harden in the brush and just give the brush a soak in lacquer thinner the next time you need to use the brush.
Just don’t try this shortcut with any kind of oil based varnish, water based finish, or catalyzed (two part) finish, unless you like replacing brushes. These types of finishes don’t dry by solvent evaporation like shellac and solvent based lacquer. Instead, they cure by an irreversible chemical reaction. This is what makes these types of finishes so “durable” but also makes them near impossible to repair without completely removing the old finish. So once these finishes cure in the brush, you can’t do anything but toss the brush.
That’s why I like to stick with shellac. For me, for all of the reasons listed above, shellac is just about the perfect finish for the home shop.
Want to see this process in action? Check out the video below.
What type of alcohol?
Everclear 190 proof (pure ethanol) is safest. Behkol shellac solvent would be my second recommendation. If neither of these are available, hardware store denatured alcohol can be used. Just be more careful with it as the denaturants (like methanol) are very toxic.
Hi, would Zinsser Bin classify as this type of shellac that you can let the brush dry then soak in alcohol when you’re ready to use? Thanks!
Yes, it would.
Hi. I’m using shellac on furniture and have a question regarding glass: Will shellac that is colored serve to stain glass or is it too susceptible to being dissolved by water condensing on the glass? I can’t find any information regarding the use of shellac to stain glass. Therefore, I’m apt to believe it is a bad idea but I’d still like to know why. The glass I would stain would only be susceptible to water condensation, i.e., it’s between two protecting pains of glass in my front door.
If you are going to put the shellac between two panes of glass, it might work. However, I’d be concerned with the shellac chipping off over time. I’m not sure how well the shellac will adhere to the glass. I’d also be concerned that UV exposure and constant temperature swings would degrade it over time, contributing to the possibility that it might flake off the glass.
With all that said, I’ve never tried it, so I’m really only guessing as to what might happen. It would be worth experimenting if you can find a couple cheap scraps of glass. I’d coat one of the pieces of glass, put the two together and put them someplace to simulate exposure for a few weeks and see what happens. You may invent a new technique 🙂 .
Thanks Bob. I wonder whether sealing with a sealer might help. I’ll let you know…