Friday, February 12, 2010

Oak bench, one coat shellac

It was with great anticipation that I started my first shellac finish with the first coat, shown here. I applied as much as possible with a rubber, which I really enjoyed as it laid down a nice smooth thin coat. For the areas not accessible with the rubber I used a soft flat paintbrush. The brushed areas were not as smooth and will require light sanding after the first coat, unlike the areas where I used the rubber. The wood already has a lovely soft sheen after the first coat.t

Some articles I read advised putting a small amount of boiled linseed oil as a first coating before the shellac to bring out the figure of the wood, but I forgot about it until too late. That'll be added to the list of things to try next time.

My shellac mixture was 4 oz denatured alcohol with 2 oz dewaxed blonde shellac flakes. I put them in an old glass jelly jar (I have started saving all empty glass jars, they come in handy for so many things) and gave it about three days to mix, agitating daily. Three days was not a calculated choice, it just worked out to be how long it took for me to have enough free time on a non-rainy day to apply the shellac.

I made the rubber out of cheesecloth (for the inside) and a piece of cotton (for the outside). I keep the rubber in another glass jar to keep it from drying out and getting hard so I can reuse it. I cleaned the brush in denatured alcohol although it is still stiff with residual shellac. However one of the articles I read assures me that once I wet it with shellac again it will be usable (another article suggested using household ammonia to clean shellac out of brushes, but I only have 28% ammonia at home - perhaps I will buy some 5% {household} ammonia and try it). Fortunately I chose a brush for which I had no other use planned.

The shellaced wood is a nice mellow aged color, although not yet as deep as I would like. My plan is to put a few more coats of shellac, experimenting with orange as well as blonde (as soon as the orange shellac I ordered arrives). To compare my results to what I started with, here is a picture I took showing the three stages of wood thus far:

Lessons Learned

1. Mix shellac flakes with denatured (ethyl) alcohol, not 91% isopropyl alcohol. Shellac + isopropyl = goop, even 9% water is apparently too much.

2. Cheesecloth is much better for the inside of the rubber than plain cotton. It holds the right amount of shellac and makes a nice and firm, unwrinkled rubber surface. I tried plain cotton first and was much better satisfied with the cheesecloth. I also read about using flannel or an old athletic sock, but I didn't try those methods.

3. Next time I would like to try putting on the finish before assembly. This piece has a lot of inside corners that were challenging to get an even coat of shellac. It would have been easier to tape the joints and shellac before assembly (I think). Next time I'll try that to compare.

4. Use shellac in a well-ventilated area. I don't have a shop to work in, so when it became too dark to work outside but I was almost finished, I took my work into the kitchen. I neglected to open the windows and ended up setting off the carbon monoxide detector. Now I make sure I can do all the work outside, then bring the piece inside and place it next to an open window.

I have never seen shellac applied in person or spoken about it to anyone. All my research came from the internet. Fine had a couple really good, helpful articles. I went to their website and searched for "shellac". I also read a nice article by finishing expert Jeff Jewitt. Or read his book, The Complete Illustrated Guide to Finishing.

The following are available on the Fine Woodworking website, but I don't know if you may view them unless you are a member:

"Padding on Shellac" from FW #112
"Versatile Shellac" from FW #166
"Sealing and Coloring with Shellac", FW video (online)

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