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Oxcilic acid?

2K views 11 replies 6 participants last post by  Rob Brown 
#1 ·
So I have this piece of trim that was installed right behind a sink...needless to say its been neglected over the years and the poly and stain was entirely gone from the stained sections. Now the stain was a semi-opaque so I was hoping after a good sanding the stain would hide the darkened wood....not so much.... Would oxcilic acid lighten the affected areas?
 

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#3 ·
I think oxalic acid would affect the entire surface. It is a bleach and as such is not selective.

You could try this in one end. I expect it would lighten the surface, and so light areas become lighter, darker areas being lighter, but not the same as the light areas.
 
#7 ·
oxylic acid

I have used it to bleach out blackened areas of walnut veneer. It was the top of a walnut buffet that was water damaged. I bleached the area involved and then sanded the entire top. Then I restained the entire top with walnut oil stain. Then a coat of dewaxed amber shellac and some polyurethane for the top. It matched the rest of the unit perfectly.The family was jealous that they didn't have the putz to do it themselves. My wife is thrilled to have it.
 
#8 ·
For the oxalic acid to have chance of working, you need to get all the prior finish off. A chemical paint stripper containing methylene chloride would be the first thing I would try.

Is there a problem with just scraping or planing the surface?

Why is this a problem now? You say is has been in place for years. From that, I assume it's in a non-visible location. If so, who cares?
 
#9 ·
If planing is out of the question (though, like Bernie said, it probably wouldn't take much) you could always just buy another piece of oak (at least it looks like oak) from the home center. Even at home center prices it might only cost $10-15 (wild guess). It only appears to be a few inches wide.

And you're sure it wouldn't work if it was 1/16" thinner?
 
#11 ·
Oh. I couldn't tell that it was profiled. I think I'd still be tempted to try planing. It may not take much. Maybe even a 32nd or so would do it. Who knows?
 
#12 ·
bleaching

can you remove the woodwork and deal with it on your workbench? If so, you can bleach it first as there isn't any finish on the blackened areas. After bleaching, then continue with stripping the entire piece and all other pieces from that window. Then start the refinishing process. Some patience is required for the bleaching to work.
 
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