Removing water staining from varnished wood

[tim]

Some of the plywood in my galley has water stained and in some cases blackened the wood where water has run down it over the years.

I'm going to sand the wood back and revarnish, but can you suggest a way of removing the staining? I did try oxalic acid to see if it woul dhave a bleaching effect, but the result was disappointing. Thanks, Tim

 

[LittleShip]

Tim
If oxalic acid didn’t do the trick try a bleach in various strengths! or leave the oxalic on longer to do its magic !

Try a post on the classic forum, those "old salts" will know what to use if this dosent work! /forums/images/graemlins/smile.gif

Tom

 

[Ruffles]

I'm having the same problem removing mould stain from a wooden mast. The problem is that the bleach dries in only a few minutes before it can have any affect.

One thing that might work is to apply the acid or bleach and then cover with cling film. This certainly works for descaling bathroom tiles!

 

[Stemar]

I cleaned some wood with a proprietry wood wood cleaner (Rustins?). It was in two parts, the first is caustic soda - paint it on and leave a few minutes, the second is 50 volume hydrogen peroxide. If you can find the peroxide, DIY would be a lot cheaper.

It might lighten the wood too much, so try a little out of the way spot first!

BTW, if it's plywood, I'd use stripper rather than sanding to remove old varnish, 'cos it's far too easy to sand right through the top veneer. Use the paste type, 'cos Nitromors can do nasty things to GRP.

 

[alb40]

Make sure the wood is dried out first, to remove the cause of the black staining, then use some teak decking restorer (local swindlery here has some made by sika - same company as sikaflex) to remove the stain. You may need a couple of goes to get a bad stain out, but it does work.

I couldnt be bothered with alot of varnishing on my boat, so the pot of white paint came out instead!