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Old 14th May 2016, 1:54 pm   #1
WaveyDipole
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Default Removing a stain from woodwork

I recently acquired a 70s vintage HiFi item that has a wooden enclosure. The top of the enclosure had a dark stain (see photo), about 3.5in in diameter. I have no way of finding out what caused the stain but I was able to remove most of it using just warm soapy water. The problem now is that the stained area has now become lighter (see second photo) than the surrounding wood. It looks like whatever caused the stain also affected the lacquer since it appears to have come away along with the stain, leaving the bare wood exposed. It is also possible that this was someones attempt at touching in the affected area. The question now is, how do I now go about repairing this? Does the whole cabinet need to be lightly sanded and then re-finished? If so, then what with?
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Old 14th May 2016, 3:52 pm   #2
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Default Re: Removing a stain from woodwork

I would try a coat of Danish oil I have used it many times and it covers a multitude of sins. It does dry to leave a slight coating though which could make further work harder if it doesn't have the desired effect.
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Old 15th May 2016, 1:01 pm   #3
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Default Re: Removing a stain from woodwork

Would you suggest using it on just the affected area, or removing the laquer from the entire cabinet?

I use Danish oil on a turntable plinth that was covered, very badly, in back paint. Both paint and the lacquer underneath had to be carefully removed before the Danish oil could go on otherwise the finish looked uneven. The result, while not perfect, looks like natural wood, but is very easily scratched. This HiFi unit cabinet is very similar in colour and does not have a high sheen, more matte/silk. I was wondering whether there was anything I could use that would given an even but more robust finish?
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Old 17th May 2016, 11:18 pm   #4
Michael.N.
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Default Re: Removing a stain from woodwork

Try a bit of gentle heat. Hair dryer on the lowest heat setting from a distance. It may just be trapped moisture underneath the finish. It isn't uncommon on Shellac surfaces, although being 70's it may be nitro. Worth a try. If it works you can use a polishing compound to revive what finish is there. If the finish is right down to bare wood you have a couple of options. Find out what the original finish is and retouch, shellac and nitro are both repairable. I wouldn't go to the effort of removing the original finish until you've tried to repair that patch.
Danish Oil isn't bad but you need to put on many coats to get a finish thick enough to withstand wear. Even then it isn't the hardest finish around. Shellac seems to dry a little harder. Nitro harder still but who wants to work with that stuff.

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Old 18th May 2016, 8:14 am   #5
SeanStevens
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Default Re: Removing a stain from woodwork

Before sealing the stain into the wood even further I'd try some more 'washing' techniques.

Try putting a little solvent onto the surface to see if it lifts the stain out. Be carefull not to make it worse, try it on a hidden area first. An alcohol will evaporate, hopefully leaving nothing behind.

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Old 18th May 2016, 4:04 pm   #6
terrybull
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Default Re: Removing a stain from woodwork

It looks like whatever the original finish was has been removed in the area of the spill. I would be tempted to carefully sand the whole of the stained panel using fine grit paper with the grain and then refinish it with Danish oil or similar.
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Old 18th May 2016, 7:18 pm   #7
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Default Re: Removing a stain from woodwork

terry, I think that is indeed the case and the initial dark stain was an attempt to repair or touch it in. Whatever it was, I unwittingly removed it by simply using a sponge and soapy water. The now lighter area is down to the bare wood which is why I was thinking along your lines.

Michael, I have never used shellac, and was unfamiliar with nitro until I just looked it up. Its possible that either of these resin finishes reacted with something spilled on the cabinet which then stripped it. I guess trying to retouch it with shellac might be worth trying, but the only place I have found it so far is online on Amazon and at £45 per litre, its horredously expensive!
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Old 18th May 2016, 8:24 pm   #8
Michael.N.
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Default Re: Removing a stain from woodwork

No, it's far, far cheaper than that. You can buy a bottle of Meths and a few hundred grams of shellac flakes for not much more than £10 or so.
Putting Danish oil on that patch may make the patch less visible but not entirely. Oil finishes direct on to wood give a different reflection to shellac and other finishes, something to do with the index of refraction. Usually oil darkens the wood a little more than other finishes.
What happens if you wet that patch with water, does it make the patch less visible?
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Old 18th May 2016, 9:22 pm   #9
WaveyDipole
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Default Re: Removing a stain from woodwork

Yes, if I wet it, then it initially gets less visible but within seconds goes darker almost like the first image. After a few more seconds it fades as it dries out and ends up like the result in the second image. I would imagine putting oil on it would similarly make it go darker so would still remain visible.

What would happen if I gently rubbed the length of the wood along the grain with meths? Would this dissolve and smudge the shellac to blend in, or would it make a mess?
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Old 18th May 2016, 11:38 pm   #10
Michael.N.
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Default Re: Removing a stain from woodwork

Well we don't know if it is shellac. Shellac will dissolve in alcohol (or at least it virtually always does). Acetone will dissolve both shellac and nitro.
Assuming that it is shellac the meths would begin to strip the finish. I say begin because you have to really go at it to strip back to bare wood, usually done with meths and wirewool or a scourer. It's unlikely to blend in, you'll have to add shellac for that to happen. It might soften the edges of that patch though. You could try applying just meths on to that patch, it might release some of the stain or blotchy nature of that patch.
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