I made a curly cherry sofa table that I finished with solvent based lacquer. I put 9 to 10 coats of lacquer and then went through successive grit sanding and then polished it to a glass like finish. The table was made several years ago and the surface of the finish has held up well.
Last winter the people that purchased the table were preparing to move and placed the table in a “Pod” for storage until the new house was completed. This pod is an unheated outdoor storage unit. The table stayed outside through all of the cold and changeable Pennsylvania weather. When they brought the table back into the house they noticed that the finish on the top had a “broken windshield” cracked appearance. The radiating cracks are very fine and appear to be below the surface. These cracks cannot be felt on the very surface and appear to be between the wood and the absolute surface.
The defect has only occurred on the surface of the top, not the legs or stretchers. My concern about refinishing the top is that if I sand off the finish I will change the patina that it won’t match the remainder of the table. Does anyone have any advice on repairing the finish without redoing the entire table? Was this a problem with the cold storage of the table?
Replies
Lacquer doesn't like expanding and contracting. Setting it out in the cold is the perfect way to make a lacquer finish look old.
It's not your fault but if the customer wants it to look like new again, it's going to need refinishing, at their expense. Leaving furniture outside is not the smartest move, IMO. This is one reason heated inside storage exists.
If you have seen guitars with the same finish, a lot of the old ones have the same thing, called "checking". Google 'lacquer checking' and you'll see more info.
You do need to refinish, but no or almost no sanding of the wood should be needed. Therefore you shouldn't disturb the patina of the cherry. Lacquer can be removed with lacquer thinner. You may even be able to "reamalgamate" the laccquer without having it totally removed. You will have to rub out the surface again. And, be neat if you don't want to have to refinish the legs and rails.
Steve, WFL said he used lacquer. I wonder which lacquer he meant? If it was pre-catalysed lacquer then, naturally, applying 9 or 10 sprayed coats is the likely root cause of the problem. This stuff, as I bet you you know shouldn't have more than three normal thickness coats sprayed on, i.e., wet films of 10-15 mils each.
A thicker dry film than 10- 15 mils will cause cracking, usually across the grain, with most pre-cats and in severe cases you end up with what I know as Chinese writing. The only one of the nitro-cellulose family of lacquers, of which pre-cat is one, that I know of that can be built up to so many coats is nitrocellulose lacquer itself.
The cure is relatively easy though. A Methyline Chloride stripper and fresh polish should do it, and this will retain the patina too. Slainte.Richard Jones Furniture
I agree, but I usually assume that when someone just says lacquer, instead of calling it pre-cat lacquer, it is old fashioned nitrocellulose, that only cures by evaporation.
The key is that whether by just dissolving it with lacquer thinner, or stripping it with methylene chloride it's the sanding that does in the patina.
Edited 12/26/2006 5:41 pm ET by SteveSchoene
That's a reasonable assumption Steve. On the other hand, I, for other equally valid reasons never make such an assumption.
Anyway,WFL has never been back to supply further information that could help narrow down the cause of the problem, which might lead to strategies being suggested to repair the job. I guess the problem wasn't really very important and we'll possibly never know. Slainte.Richard Jones Furniture
Martin guitar company and other guitar manufacturers will not ship their products in the winter months for this reason - cracked finishes. Rich
Some people pay extra for a crackel finish.
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