bubbles in lacquer after drying

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Forum topic by MalcolmLaurel posted 04-29-2014 10:41 PM 2880 views 0 times favorited 4 replies Add to Favorites Watch
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300 posts in 1863 days

04-29-2014 10:41 PM

Topic tags/keywords: question finishing pine

So here I have this live edge table I recently finished. The tabletop has 5 or 6 coats of Zinser dewaxed shellac, left to dry for about a week, then 3 coats of Watco gloss lacquer. Looked beautiful (and still does, from a distance). Did the lacquer on a Tuesday, then on Thursday night I wrapped the table in a blanket to protect the finish and put it in my car to take it up to the cabin the following day. Got rather warm in the car in the parking lot at work on Friday morning, so after lunch I left the windows cracked, and drove up to the cabin after work.

When I unwrapped the table, there were two small (about 3/8” diameter) bubbles in the finish, and another slightly rough area, all of which I’m pretty sure weren’t there before. I’m guessing the heat made something outgas and perhaps softened the finish in one spot… anybody see anything like this before? One of the legs (which are just shellac with no lacquer) stuck to the blanket but it didn’t leave any mark.

I pricked the bubbles with a pin and they pressed down flat, but still show. At this point I’m debating how (or if) to fix it. I guess the thing to do is to sand it all over, sanding the bubbled areas down to the shellac, and recoat with more lacquer, laying it on heavy over the bubbled areas?

-- Malcolm Laurel -

4 replies so far

View tefinn's profile


1222 posts in 2677 days

#1 posted 04-29-2014 11:08 PM

Lacquer is very easy to fix. Each new coat will dissolve into the previous one. As long as it’s not an adhesion problem, I’d just spray some fresh lacquer over the damaged areas after a light scuff sanding. In some cases, all you need to do is lightly spray some lacquer thinner on the finish and the imperfections will melt back into itself. If it’s an adhesion problem, you’ll need to address that so the finish won’t do the same after the repairs are made. There may be a contamination (wax, oil, silicone, etc.) on the surface of the wood preventing the lacquer from sticking. If that’s the case, you’ll need to sand down to the wood and refinish. Most likely though, the finish wasn’t cured enough and the heat just softened it.

-- Tom Finnigan - Measures? We don't need no stinking measures! - Hmm, maybe thats why my project pieces don't fit.

View MalcolmLaurel's profile


300 posts in 1863 days

#2 posted 04-30-2014 11:07 AM

Lacquer melts into old coats? I didn’t know that; thought only shellac did that.

-- Malcolm Laurel -

View MisterBill's profile


411 posts in 2491 days

#3 posted 04-30-2014 11:32 AM

How dry was the wood? What you are seeing could be “blisters” caused by moisture that is in the wood. I had a similar thing happen to me once.

View Earlextech's profile


1162 posts in 2930 days

#4 posted 04-30-2014 02:52 PM

I would first try a light coat of lacquer thinner. Adding finish can add problems.

If that doesn’t work, lightly sand with 220, then spray with lacquer. Yes, lacquer dissolves the previous coats.

I’m with tefinn on this. If neither of those work, you may have contamination, which means more sanding.

-- Sam Hamory - The project is never finished until its "Finished"!

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