Help: Streaks in shellac

[John TenEyck]

I'm working on an antique with a shellac finish. There was some solvent, water, and physical defects in several areas so, after cleaning it with mineral spirits, I wiped them with a 50/50 mix of Sealcoat shellac and DNA. In most areas it came out beautifully, but in a couple I got dull streaks as the finish dried. I was able to get rid of those streaks in most areas by wiping with a wetter rubber an hour or so later, but in the most important area they would not go away. I even resorted to a brush on layer and the streaks are still there.

What do you think is causing these streaks? More importantly, how do I get rid of them? Thanks in advance.

John

[John Coloccia]

I'm working on an antique with a shellac finish. There was some solvent, water, and physical defects in several areas so, after cleaning it with mineral spirits, I wiped them with a 50/50 mix of Sealcoat shellac and DNA. In most areas it came out beautifully, but in a couple I got dull streaks as the finish dried. I was able to get rid of those streaks in most areas by wiping with a wetter rubber an hour or so later, but in the most important area they would not go away. I even resorted to a brush on layer and the streaks are still there.

What do you think is causing these streaks? More importantly, how do I get rid of them? Thanks in advance.

John

Can you post some pictures? DNA, IMHO, is not ideal for shellac. I pretty much use Bekhol for all of my shellac now. Not all alcohols are equal. If it flashes off too quickly, it won't flow out properly. Anyhow, post a picture. I suspect that the dull features are not dull at all, but are blushed. DNA, especially older DNA, can have an awful lot of water in it, and it can certainly blush the finish. Are the dull streaks kind of cloudy? If the solvent flashes off too quickly, you can certainly get blushing.

[Mel Fulks]

I agree, I used to be able to use reg DNA. Now it's no good. Use Behkol and put the top back on immediately,it draws moisture from the air.

[John TenEyck]

Yeah, could be water. I have some Behlkol and will give it a try. Thanks. I'll let you know how it turns out with some before/after pics.

John

[John TenEyck]

Well, the Behkol didn't help. This photo is some point in the debacle.

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I even tried removing some of the finish with a plastic scraper, but that did nothing but make it obvious that I had to strip it all off.

247751

So that's what I did after masking off the surrounding areas. That went very well, the finish came off about as fast as I brushed on the stripper and it wiped off cleanly with fine steel wool. I then wiped it with MS a couple of times and let it dry for several hours. Then I mixed up a dye of Transtint Brown Mahogany in DNA with a little amber shellac to give it some body and color and wiped that on.

247752

I then moved the piece into my temporary spray booth and sprayed on the same mix with my touch up gun, adding multiple coats to a sapwood area at the back of the shelf, and only one or two light coats on the entire shelf to help darken it towards the color of the rest.

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You might be able to see that the sapwood is greatly diminished now. Anyway, when that had dried a while, I sprayed on a 50/50 mix of Sealcoat shellac and DNA, at 5 light coats I called it good.

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Not as smooth as a padded on finish, but since I've never done it this was no time to try it. But it looks plenty good enough, and the damage that was there is gone and the color is uniform. The underlying wood is a very pretty quilted mahogany which shows through quite nicely now.

John

[glenn bradley]

Great save John. Glad you got it cleared up.