Bleaching wood with Oxalic - advice please

[skyflyer]

I am re-finishing my cabin sole boards, which are the standard teak and holly strip, veneered on ply.

I have stripped the old varnish using a combination of a hot air gun and chemical stripper.

Parts of the holly are discoloured - particularly at the edges of the board where presumably* moisture has wicked up - varying from dark brown to grey. Some of the teak has darkened or blackened in small spots - usually where there has been a dent in the old varnish that has broken the surface and allowed damp to penetrate.

I have made up a concentrated Oxalic acid solution and applied it to these stains and the effect has been... zero! I am using about 30g of OA in 100ml water which will only dissolve if the water is very hot so I think its max concentration! As it cools on the wood the crystals precipitate out, eventually!

What am i doing wrong. Is it the "wrong sort of stain"?

Thanks in anticipation

(*prior to me buying boat, I guess)

 

[yoda]

use bleach and then neutralise with 50:50 vinegar and water 24 hours later.

Yoda

 

[Tiller Girl]

Pretty strong mix there which is probably precipitating. It will need repeated use of OA. Personally I would not like to use bleach because advice in my little book says that some - for example Cuban mahogany - cannot be used and all woods can have a dramatic effect - for example with Honduras mahogany leave almost white! Absolutely critical to remove the varnish, every little bit.

 

[Pcd]

I had good results using 4 or 5 washes with oxygen bleach/sodium percarbonate before the oxalic. Google something like oxygen bleach/sodium percarbonate mildew for info.

 

[yoda]

Pretty strong mix there which is probably precipitating. It will need repeated use of OA. Personally I would not like to use bleach because advice in my little book says that some - for example Cuban mahogany - cannot be used and all woods can have a dramatic effect - for example with Honduras mahogany leave almost white! Absolutely critical to remove the varnish, every little bit.

Yes but we were asked about teak and holly on which I have had good results from some very dire starting states. As always testing on an inconspicuous place is advisable but up to the OP.

Yoda