Using Oxalic Acid to bleach wood

[Lastkozak]

Hi,

I have read the thread on bleaching stains from wood. Oxalic acid seems to be the chemical for dark stains, however what if the stain is the result of somebody painting over the wood?

I have sanded all I could, but the dust film of the colour (red) is still visible, and some paint is still in the larger pours, and I would like to varnish it. Will Oxalic acid remove or bleach this red dust in the pours of the wood?

Or should I keep sanding: I am fearful that sanding will decrease the dimension of the wood too much.

Last Kozak

 

[mccloud]

I have used oxalic acid to lighten old, dark wood, but I do not believe you will see any improvement if you treat red paint with oxalic. A chemical stripper, particularly one with dichloromethane (methylene chloride) may soften the paint just enough that you can get it out with a brush. You are correct that it is possible to sand too much. Tom McCloud

 

[Cliff Ober]

Oxalic acid is primarily for removing metallic stains (e.g., rust), and it won't do much else in bleaching wood.

Cliff