Sunday, May 1, 2011

Back is sealed


I sealed the back today. I was going to seal the belly as well, but I found a place where the purfling was carved away and had to fix it. The first step is to burnish the entire back, edges and everything. Then I brush on a liberal coat of gum dissolved in water (60:1 water), let it soak in for a minute or so, blot off the excess with a paper towel. After it feels almost dry I burnish it again. Same sequence again, this time with liquid resin. After this it was nearly sealed. The last methods I used needed more coats than this. Most of the spots that were not sealed as well were near the ends where there is a lot of end grain. So I soaked the ends with some gum again, rubbing some around the rest of the back. After blotting it off I followed with the resin, and when it was almost dry I burnished it up.

At this point it seemed to be at a good point for the final seal coat. I want the top coat to go on when the wood is ALMOST sealed. I want to FEEL a little wood through it. I hope that after the final coat, THEN it will feel sealed. After that the varnish goes on, and if it chips or wears off, the sealing (ground) is still there.

The final coat is a very light coat of very dark varnish I cooked up a while ago. It's like a Fulton varnish with added resin, and no turpentine. It is very thick. I put a bit on a small, stiff artist brush, and use it like a stippling brush. Then I use my fingers to spread it around. It isn't brushable, only the fingers and hand can spread it around. It doesn't take long, and only uses a minuscule amount of varnish. How's it look?

2 comments:

  1. Gorgeous! Is there a reason to seal the plates before assembly?

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  2. Thanks. I heard other makers say that sealing and varnish may affect the tuning, so I decided to seal them and see if the tuning changed. I haven't noticed anything on the back with the tap tones. I'll put it on my tuning fixture and check it out today. I did find that it is easier to put the thin varnish coat on the edges with the plate off the ribs though, and to burnish the edges.

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