Help with water stained Wood

[martinwoolwich]

In the process of moving my boat out and back in over winter, it seems that a small leak appeared in the seal around one of my hatches.

No-one noticed that over time, water was leeching into the headliner (foam backed) and then all the way across the top of a light ash veneered bulkhead.

The leak has been fixed and the wood is drying out but this has lefty a very nasty stain into the wood (it looks like someone has smeared marmite into it).

To touch, the wood feels smooth so I assume the stain is directly into the grain of the veneer and not got between it and the ply behind.

At present I am told that the only way of dealing with this problem is to fix a matching piece over the stained part ( we're talking about 6ft by 2.5 inches) which I think will look really bad.

Does anyone know of any way I can get the stain out - bleach?, sanding? special cleaner? I just don't know what will work and since it's in such a prominent position exerimentation could be a disaster.

Equally, this is a structural bulkhead attached into the GRP so removal for repair is completely out of the question.

Any help would be very much appreciated.



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[ccscott49]

sand the varnish off, then apply a weak solution of oxalic acid (teak brightener) it might work, better than replacing the section.

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[Blue_Blazes]

See thread from about a week ago. "Oxalic acid".

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[Oldhand]

Sugar soap removes water stains from clean teak.

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[ronniewood]

Oxalic acid works very well but if on a bulkhead the only way I have heard of it being effective is to make up a wallpaper paste including the diluted acid granules and applying to the area. Its then a suck and see on how long it could take. May need a number of applications depending on how deep the staining is. Can be hard to obtain but I eventually got it from a company that supplies school labs.

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[alanporter]

I had a similar problem and managed to remove the stain with naptha.

<hr width=100% size=1>Alan Porter

 

[AndrewB]

I've also found oxalic acid preparations best with black water marks under varnish (sugar soap with black oil stains in wood). But it won't leave a perfect finish. You will have to gently sand back the wood afterwards, very carefully if its a ply veneer.

I believe the black marks cause by water are in fact the early signs of wet rot, so this job is not just cosmetic. It's not a problem with hardwood, which is resistant to rot, but with soft wood I would recommend a Cuprinol treatment before recoating.

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