White Specks in Mahogany Veneer Problem - Woodworking Talk - Woodworkers Forum
 
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post #1 of 3 Old 03-01-2020, 03:15 PM Thread Starter
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White Specks in Mahogany Veneer Problem

I am refinishing an antique mahogany veneered radio. I stripped it and very lightly sanded it but did NOT stain it. Then I applied a coat of MinWax Polyurethane.

When I went to apply the second top coat I noticed white specks everywhere and sure did not notice them earlier in the process.

I tried a couple of colours of MinWax PolyShades (of which I am not a big fan) because it okay to apply that over polyurethane. The white flecks did NOT disappear. The first picture shows the white specks problem.

Then I stained an area with Saman (a Canadian water based stain) and the specks did disappear as you can see in the second picture.

I have been refinishing as a hobby long enough to not want to mix oil and water products this way. I would appreciate feedback on what my risk is of proceeding.

Thank you.

Gary
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post #2 of 3 Old 03-01-2020, 07:23 PM
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Iím kind of surprised that the stain fixed the white spots since the wood was already sealed with the polyurethane. Oh well, I guess youíve got to take the good with the bad. 😀

Let others weigh in, but I think oil over water is safer than water over oil. To ensure good adhesion over the stain, I would make sure that the stain is fully dry and that any excess is removed. Poly is notorious for bad adhesion to subsequent coats,so donít give it any help. You donít want any film sitting on the surface that could prevent the next coat of poly from sticking. Iíd sand what youíve got to make sure it has some ďtoothĒ for the next coat to grab. If you want to play it safe, sand and apply a coat of de-waxed shellac before going back to poly. Actually, the original finish may have been shellac.
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post #3 of 3 Old 03-01-2020, 11:43 PM Thread Starter
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Quote:
Originally Posted by Quickstep View Post
Iím kind of surprised that the stain fixed the white spots since the wood was already sealed with the polyurethane. Oh well, I guess youíve got to take the good with the bad. 😀

Let others weigh in, but I think oil over water is safer than water over oil. To ensure good adhesion over the stain, I would make sure that the stain is fully dry and that any excess is removed. Poly is notorious for bad adhesion to subsequent coats,so donít give it any help. You donít want any film sitting on the surface that could prevent the next coat of poly from sticking. Iíd sand what youíve got to make sure it has some ďtoothĒ for the next coat to grab. If you want to play it safe, sand and apply a coat of de-waxed shellac before going back to poly. Actually, the original finish may have been shellac.
Thank you. Some good feedback. Dryness is not an issue. Light sanding seems like a good idea. And I will go with diluted Zinsser SealCoat to improve the adhesion on the next top coat.

Gary
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