Fixing Shellac

[Chris Jenkins]

Well last night my project went from ok to bad. I tried Amber Shellac by Zinsser for the first time. I added some denatured alcohol, but I don't know if I added enough to call it a 2# cut. Either way it was thinned a bit in hopes of a longer working time.

Here is my problem (aside from not liking the tint on the maple, looks good on the cherry though). I got some spots where I had some light sagging or runs (actually they are rings, maybe drips?). Will this go away when I rub in the next coat? (I've heard Shellac melts one coat into the next) Or will I need some 400 and mineral spirits to sand this down lightly before the next coat?

Also I started with cotton rag and this seemed to go on too light, then I switched to a brush (mainly to get into tight corners without flooding them) and this seemed to go on a bit heavy. What do you guys recommend?

Thanks,
Chris (pics soon!)

[Ralph Dobbertin]

Apply with a pad or a proper shellac brush made from badger hair like this one. http://www.leevalley.com/wood/page.aspx?c=1&p=30271&cat=1,190,43034

Careful with the corners, shellac can be tricky because it dries so fast.

Depending on how thick your drips are you should be able to rub them out with the next coat, but you may need to scrape out the goop in the corners.

Your pad should have cotton balls rolloed up inside the cotton cloth. The cotton can be wetted with alcohol, and the technique to use the pad is like a plane landing and taking off...One full pass.

[Steven Wilson]

Brushing shellac requires a different technique and good brushes. Go see Jeff Jewitt for the brushes. For corners I use a Windsor & Newton #580 brush and then out in the field I general pad on shellac, use the WN, or an Omega Lily Oval Varnish brush. For drips and runs I like to remove them with a single edge razor blade or if a larger flat area needs work I like to use a card scraper without a hook turned on it - fantastic for leveling a finish. Also with shellac you don't apply one coat at a time. In one sitting you generally apply 2,3,4,5 or more coats and then stop once things start getting sticky. If you can flow shellac on then keep applying coats. Once it gets a bit tacky stop and let the piece dry.

[Chris Jenkins]

Oops, yeah used a cheap-o foam brush. Sure that makes a big differance. I'll switch back to the clean cotton rags.

I did keep putting on the Shellac and then it did start getting tacky. I tried to get a bit more on to keep from getting tacky, but clearly I couldn't beat that, so I stopped.

[Howard Acheson]

Two points. Thinning shellac with denatured alcohol will not slow down the drying time. In fact, it somewhat accelerates it. The proper cut for brushing is 1 1/2# - 2#. Shellac is flowed on using a good natural bristle brush. Do not use a sponge type applicator. Denatured alcohol dissolves foam brushes.

For the best finish--if not planning to overcoat with something else--us the padding technique. Brushing multiple coats of shellac can be problematic.

[Hal Flynt]

What Steve says about the card scraper and razor blades for the runs.

I have some 99% isopropyl alcohol that I use to retard the drying and help flow it out. (I have also used the 97% isopropyl from CVS with no ill affects).

[Steve Schoene]

The key thing to think about applying shellac is quick. Brush in one direction only, never going back. That's why I like the watercolor wash brushes such as the Winsor Newton 580 or others made with Taklon gold filaments. These brushes don't hold a lot, but they do apply thin even coats that barely have any brush marks that need to flow out. If you miss a spot pick it up on the next coat. Stop as soon as you feel the surface have any drag. When dry shellac sands or scrapes easily so things like runs or drips can be handled that way. It is folly to try to redissolve shellac to move it around. Each coat does dissolve into the next, but you want that to happen after you have moved away with your brush or pad.

Though it does take a different technique than applying varnish, it's not hard once you get the hang of it, and shellac is just about the only finish that you can get a very nice finish applied in one weekend. It's also just about the best looking finish around, and a lot tougher than many give credit for, so its well worth making the effort to get the hang of it.