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Black stains after stripping oak table - any suggestions?

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TCR

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As the great waldo pointed out the table is made of two different materials; the top is coarse textured ring porous oak and the underframe is fine textured diffuse porous beech. There are remnants of the old pigmented varnish lodged in the pores of both wood species. In the oak it is mostly apparent lodged in the distinct dark bands of the coarser and more open spring growth. In the case of the beech which has a fine grain lacking a marked distinction between spring and summer growth density and texture the remaining pigmented finish is relatively evenly spread throughout the small pores of the timber's surface.

I suspect the bleaching options suggested by others, whether you use A+B bleach or oxalic acid, or both, won't remove the black colour from both the wood species. If either or both of the bleaches work then you could follow up with a dye of your choice and refinish with varnish or similar. If, on the other hand, the bleaching strategies don't work you might consider applying different finishes to the different parts. You could, for example, paint or dye/stain plus polish the underframe one colour and finish the oak top just with a clear finish, such as an oil varnish which itself will darken the oak, but leave the dark pigmented bands of coarse spring growth.

I don't think you'll ever be able to get the underframe to closely match texturally the appearance of the oak because the two wood species have different texture (coarse and smooth or fine), but you should be able to get a close colour match by finishing both with a dark stain or dye plus polish. However, that is the look you've just removed and you want to get away from that, so maybe the two different treatments for the two wood species you're dealing with might be worth considering. Slainte.
Wow, thanks for the extra detail on the various grains and the advise on possible alternatives. e.g. the legs being different colour from the base. This is a last resort but might end up the pragmatic solution. We like the darker grain detail on the top so that won't be a problem - it is the legs that just look patchy. Anyway, let's see how the Oxalic acid works. The whole purpose of the exercise is to get away from the dark finish, hence striving to solve the problem rather than cover it up. Thanks again for the level of detail, much appreciated.
 

TCR

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Hi Tim
Tonally the sanded top doesn't look too far off the shade of the legs. I would first wet down the wood with some meths, and see how the shades match up. Then use some thing like a spirit based golden oak for the whole lot and then use a slightly darker shade of oak to blend the shades till legs and top match. By the way oxalic acid is pretty good for clearing dark stains unless the stains are pigmneted. You could try using a small brass wire wheel thingy in a dremel which should get you into the corners without too much damage. Try staining light at first ( you can always go darker) I think with a little colour the dark bits won't be so obvious and you may get a nice effect. Try and make sure the stains are light fast Morrells alcohol stains used to be really good (at least 30 + years ago when I used to buy from them!)
Cheers
Andrew
Thanks for the info on the stains. The "finishing" was due to be phase two, but as you point out, the new staining could end up solving the problem with the old residue.
 

TCR

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As the great waldo pointed out the table is made of two different materials; the top is coarse textured ring porous oak and the underframe is fine textured diffuse porous beech. There are remnants of the old pigmented varnish lodged in the pores of both wood species. In the oak it is mostly apparent lodged in the distinct dark bands of the coarser and more open spring growth. In the case of the beech which has a fine grain lacking a marked distinction between spring and summer growth density and texture the remaining pigmented finish is relatively evenly spread throughout the small pores of the timber's surface.

I suspect the bleaching options suggested by others, whether you use A+B bleach or oxalic acid, or both, won't remove the black colour from both the wood species. If either or both of the bleaches work then you could follow up with a dye of your choice and refinish with varnish or similar. If, on the other hand, the bleaching strategies don't work you might consider applying different finishes to the different parts. You could, for example, paint or dye/stain plus polish the underframe one colour and finish the oak top just with a clear finish, such as an oil varnish which itself will darken the oak, but leave the dark pigmented bands of coarse spring growth.

I don't think you'll ever be able to get the underframe to closely match texturally the appearance of the oak because the two wood species have different texture (coarse and smooth or fine), but you should be able to get a close colour match by finishing both with a dark stain or dye plus polish. However, that is the look you've just removed and you want to get away from that, so maybe the two different treatments for the two wood species you're dealing with might be worth considering. Slainte.
Thanks Sgian, you make excellent points. Much appreciated.
 

TCR

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Update on finished table legs with black dye residue stains. Thanks again for all those who made suggestions. As many suggested, the problem was a bit of a lost cause and the bottom line was, the stains could not practically be shifted. I tried: Oxalic Acid, Wood Bleach, Hydrogen Peroxide, White Vinegar, Lots and lots of elbow grease with 80 grit. In the end we took the pragmatic approach and stopped trying to remove and instead, live with the results. Finished the bare wood with Rustins Medium Oak wood dye followed by a coat of Ronseal matt water based varnish, then a coat of Wickes Walnut water based varnish, quick rubdown with 600 wet and dry and then finished with a final coat of the Ronseal clear matt varnish. I went for the 2 clear and one walnut because I didn't want to get too dark. We were VERY happy with the top of the table and the legs with the various finishes looked passable and match the chairs very well. Photos attached. Now onto the next project - restoring an old Pixiphone xylophone !
 

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the great waldo

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Hi Tim
You've done a great job on that. The warm colour on the top is really good. Just watch out for sloshing red wine on it as it goes really deep into oak (don't ask me how I know)

Cheers
Andrew
 
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