Oxalic Acid Wood Bleach Remove Tough Stains From Wood

There are two types of water stains that you may find on your wood flooring or furniture The most difficult one to remove is the black stain which indicates that the water has seeped beyond the finish and into the wood. I do, however, recommend you strip the piece to bare wood to make sure there will be no finishing problems. Once your stain is selected and on your final project, let it dry and apply two coats of dewaxed shellac to seal the knots. But now that the stain is applied, I recommend carefully sanding the entire surface to remove the stain and start over. By all means, do as you wish, but a shame to darken antique oak furniture in some instances.

You have two options: Dip a small brush into a small amount of bleach and rub onto the stain; do a second round after several hours and let the area rest until the next day. If desired, apply a second coat of Waterborne Colorwood Rock Salt or Egg White and wipe off the excess leaving touches of white or cream limed stain behind to softer the base colour. I’ve tried sealing with shellac first but the glue is still showing through the stain. Oak is commonly used because of its high tannic acid content, and walnut is a very reliable wood for ebonizing.


Hi Angie – If you want to paint the piece, not use black stain on it, you do not have to remove all the poly, but you do need to sand the surface to provide some tooth” so the paint has something to adhere to. You mentioned the piece has a lot of poly on it. If this is so, when painted over…you may see all the imperfections in the level of the poly.

Right now I’m looking at some raised grain after staining, and some uneveness..wondering if I can combine some steel wool work to remove just some uneveness and more stain around the edge…also, that deep glow from lacquer coating….most guys aren’t set up at home for spraying, but tung oil layers aftere a single linseed coating have a great look, but don’t expect the magic till after the 6th or 7th coating….

Cover the stain with a dry cotton cloth and rub with a hot iron (set to no steam) for two to three seconds. Leaving wood outside uncovered for long periods also causes ultraviolet erosion of the wood. One easy way to make dark wood stains is to just make your all natural DIY stains darker. To start with, I created a basic stain to which I would be adding the food coloring. To take care of this, saturate a rag with the oxalic acid solution and wipe a thin coat over the stain and surrounding area. One section on the sample, i dampned with water and pulled some stain off and i can see some glow, but the color of the stain got weak.

Remove the stain from selected areas, usually edges and corners, using p180 to p220 grit sandpaper. If you notice any subtle lightening of the normal wood color in the area of the stain as a result of the application, you can apply a coating of the paste to the entire surface being treated, so that the color remains consistent over the whole surface as the stain is being treated. Based on your other posts I’m thinking of a seal coat using zinnser no wax shellac based sealer, then gel stain. Sand the whole table again (wood filler included) with a higher grit paper until it’s smooth and even. This will give you a totally black finish but still leave the impression of the wood’s grain.