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Stained wood
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=51274		 Page 1 of 1
Author:  Dave Rickard [ Sun Nov 25, 2018 10:41 am ]
Post subject:  Stained wood
I left a clamp laying against a piece of wet Black Limba and it left a stain.
Aside from kicking myself for being a "Dumb Dave" is there some way to get rid of the stain.
The wood is about .05 thick.
Author:  BradHall [ Sun Nov 25, 2018 11:11 am ]
Post subject:  Re: Stained wood
My inclination would be to try oxcylic acid. Works great on stained redwood and cedar. Try a small test sample first. Available at most lumber yards.
Author:  Chris Pile [ Sun Nov 25, 2018 11:50 am ]
Post subject:  Re: Stained wood
That's 2 votes for oxalic acid, Dave. Buy it in powered crystals and mix up a little bit. Make sure you rinse the wood after to remove the acid before sealing and finishing.
Author:  Clay S. [ Sun Nov 25, 2018 1:27 pm ]
Post subject:  Re: Stained wood
Make sure you keep the crystals and any solutions in a safe place. Oxalic acid is a poison if ingested.
Author:  Ruby50 [ Sun Nov 25, 2018 4:43 pm ]
Post subject:  Re: Stained wood
I had to use OA on a piece of furniture maple - just a local spot. I mixed it weak and it still left a spot that is much lighter than the surrounding light wood. I would definitely try it on a scrap piece first.

Ed
Author:  B. Howard [ Mon Nov 26, 2018 8:16 am ]
Post subject:  Re: Stained wood
That may be a permanent feature on a wood like limba. If you use wood bleach like mentioned you will need to do all the pieces completely to keep it matching in color. Having had a similar situation on white oak when I was doing custom staircases I doubt you will have a high level of success.
Author:  Joe Beaver [ Mon Nov 26, 2018 11:15 am ]
Post subject:  Re: Stained wood
What does the other side look like? If the discoloration went all the way through then there would be no saving it. Otherwise maybe you could scrape it off? At .05" it is already to thin for most parts of a guitar except maybe a head plate or as part of a laminate, so I am wondering what you were planning for it?
Author:  Woodie G [ Mon Nov 26, 2018 5:12 pm ]
Post subject:  Re: Stained wood
In general, you want to brush on the oxalic acid over the entire area, rather than work a small spot to get as even a color as possible. When the mixture dries, the unreacted acid will have to be neutralized with a basic solution - baking soda or borax (washing soda) works, followed by a distilled water wash. If dry oxalic acid is not readily available, deck brighter (used to brighter decking and other outdoor bare wood) contains dilute oxalic acid, and is quite handy in the shop and a bit less ferocious (sorry for the pun).
Author:  jshelton [ Mon Nov 26, 2018 6:41 pm ]
Post subject:  Re: Stained wood
from my experience with the same thing, Brian is correct. It's pretty much hopeless.
Author:  Ken Lewis [ Mon Nov 26, 2018 9:15 pm ]
Post subject:  Re: Stained wood
I would try sanding as a first measure as the stain may not be very deep. This won't worsen the situation so nothing to loose.

I see it's only .05 thick so maybe not:)
Author:  B. Howard [ Tue Nov 27, 2018 8:12 am ]
Post subject:  Re: Stained wood
Scraping will be hard..... this stain did not come from the metal of the clamp, it is not rust on the surface, in fact the metal likely had little to do with it.... What we are seeing is how the water wicked the tannin out of the wood, these stains go fairly deep typically.
Author:  Dave Rickard [ Tue Nov 27, 2018 8:33 pm ]
Post subject:  Re: Stained wood
Thanks for the tips. Oxalic acid is the primary active ingredient in bar keepers friend.
I have some cut offs to try it on. I'll try to replicate the stain and then see what happens.
I'll report back when I get home.
Author:  Goat Rock Ukulele [ Tue Nov 27, 2018 11:16 pm ]
Post subject:  Re: Stained wood
I have heard Petrolium Jelly works. You know that pink stuff. I have never tried it.
Author:  Clay S. [ Wed Nov 28, 2018 3:15 pm ]
Post subject:  Re: Stained wood
"I have heard Petrolium Jelly works. You know that pink stuff. I have never tried it."

Naval Jelly?
Author:  Dave Rickard [ Sat Dec 08, 2018 8:57 am ]
Post subject:  Re: Stained wood
We made it home, finely.
I've been trying to stain a piece of cut off and having no luck.
Wood from the same board same distilled water same clamp leaning against it.
Let it set for 4 days,the other was 2 days.
No stain!
OMG I'm even a failure at ruining wood!
Author:  Dave Rickard [ Sat Dec 22, 2018 11:25 am ]
Post subject:  Re: Stained wood
Back home and in my shop.
I picked up some Savogran oxalic acid and practiced on some off cuts that I stained.
I also tried Bar Keepers Friend it's active ingredient is oxalic acid.
Both worked about the same so I used the Savogran.
I used a toothbrush to scrub and then wiped it clean with a wet paper towel and then dried it with a dry paper towel.
Three treatments about a hour between each I happy with the out come.
Thanks to everyone for the help.
Author:  Clay S. [ Sat Dec 22, 2018 11:35 am ]
Post subject:  Re: Stained wood
It looks like you eliminated most of the stain. If you find it becomes more noticeable under finish, you could tone the top coats.
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