Wood bleach mistake

[maori123]

Please can someone give me some advice on finishing an old pine floor. My builder advised me to use to some wood bleach on a few areas that couldn't be sanded out. I used Liberon wood bleacher, which is apparently oxalic acid, and the result looked fine, no visible difference overall between the bleached wood area and the non bleached. Then I applied Blanchon Wood Oil Environment and the result is a disaster - in the bleached areas the oil turned milky and a bit sticky and took ages to dry, the finished effect is a patchwork of colour! I have now sanded it back again, but I'm unwilling to do anymore without some advice. Will rinsing the whole lot with a baking soda solution do the trick, or do I need to bleach and wash the entire floor? I had rinsed the bleached area with water as advised on the bottle, maybe not enough. I just need to even out the effect of the bleach, which only shows when it's oiled.
Any advice would be gratefully received.

 

[CHJ]

No solution I'm afraid, but is sounds as if you have just bleached the colour out of what ever the finish was that could not be sanded out, this is sealing the wood and preventing your oil finish application penetrating evenly.

Think it may be a case of applying a finish containing a pigment dense enough that will coat and seal the surface rather than trying to penetrate with a colourless oil.

I'm no expert on floor finishes but that seems to be the problem you are describing regarding the blotchy finish.

 

[custard]

I have now sanded it back again

As long as you did a thorough job then you're good to go. If you want to check try damping different areas of the floor with water and seeing if they all turn a uniform colour. Any problems then keep sanding.

 

[Mr T]

As said before it looks like the varnish you hadn't removed has stopped the new finish from taking. When you resanded did you also do the bits you weren't able to do before? If not they need to be sanded or the original finish removed in some way. If it's a problem of getting a sander to it you could try scraping then hand sanding.

Chris

 

[maori123]

I'm not sure if I've made myself clear. The floor was thoroughly sanded and then I applied bleach to random areas. Where the bleach was applied the oil is bringing out the change in colour making the floor look patchy. I have sanded it back again but I don't know what to to avoid the patchy finish caused by the bleach. Thanks for the advice offered so far - if I put a stain on, won't that also be patchy depending on whether it's on a bleached bit or not? Would I be better to bleach the entire floor or would that result in the bits that are already bleached being bleached even more?!

 

[CHJ]

But initially I suspect you only bleached the colour out of whatever it was you did not manage to sand out, is it still there or has your recent sanding removed it altogether.

If not anything that relies on soaking into the wood will have the same problem, be it oil or stains, its penetration and reflective nature will be influenced but the 'contamination' for wont of a better word, albeit it has been bleached to look the same alongside the bare sanded wood.

I'm not sure the bleach is the problem, I think it is the remaining product that you bleached that is still in the pores of the wood.

What do the patches look like if you wipe over with a water soaked cloth.

 

[Matt@]

after you bleached you said you washed it with water. How long after the water did you leave the wood until you oiled it and is the room where the floor is heated?

 

[maori123]

I left it quite a few days and at the moment there is no heating in the room. I think I'm going to have bite the bullet and re-sand the room. The tip about wetting the wood to identify the bleached patches is good one, thanks.

 

[Myfordman]

I wonder if the treated areas are remaining acidic despite washing. I can imagine acidity of the substrate affecting the behaviour of the coating. Moistening the area and pressing on ph indicator papers would test this.

 

[ED65]

It isn't clear how much, if any, rinsing was done initially. Could you describe how you washed off the surface after bleaching?

Oxalic acid needs to be rinsed very thoroughly from wood so as not to cause problems with subsequent finishes. With wood that can't have flowing water run over it you really need to sponge over it at least three times.

Will rinsing the whole lot with a baking soda solution do the trick...

Assuming you didn't rinse thoroughly enough rising again with a solution of baking soda sounds like a good idea except for one thing, basic solutions chemically interact with softwoods to make them various shades of yellow!

 

[mrpercysnodgrass]

I think everyone that has replied to you has pretty much covered everything, as ED65 said, rinse at least three times preferably with warm water, changing rags frequently. All i can add is that whenever I use bleach on furniture whether it be oxalic or A+B I always bleach over the whole area to avoid any unevenness of colour when finishing.
The only other thing that came to mind was....The areas that could not be sanded out, why could they not be sanded out? If these areas have been affected by some sort of rot or had some sort of chemical sat on them that has changed the structure of the surface then bleaching will probably not work and you may have to resort to chopping in new sections in or even replacing whole boards.
Some photos might help!

 

[andersonec]

What if you bleached the whole floor and make it all the same colour?

Andy