White Oak Damage from Rusted Water

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Forum topic by Syellin posted 04-20-2018 06:38 PM 1212 views 0 times favorited 34 replies Add to Favorites Watch
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9 posts in 1907 days

04-20-2018 06:38 PM

Topic tags/keywords: question white oak fix

I am in the final stages of completing a small table out of white oak, and had the table base assembled and waiting idly in my basement shop for final sanding to prepare for finishing. One major rainstorm later I have an inch of standing water in a corner of my basement where the table base stood, with visible rust in the water from an old drain pipe leak. White oak and water with iron don’t play well together, and my pristine table legs are now disfigured with black “tips”. See images.

Does anyone know of a way to remove the black stains, or is this permanent? Trying to figure if i should just cut off the bottom inch and have a shorter table or try to cut it off and patch it. The patch would be tricky as the table legs have a double taper. Not ideal.

Any ideas would be welcome.

34 replies so far

View bilyo's profile


1112 posts in 1878 days

#1 posted 04-20-2018 06:55 PM

Oxalic acid should do the trick.

View chrisstef's profile


18094 posts in 3782 days

#2 posted 04-20-2018 07:09 PM

2nd the oxalic acid

-- Its not a crack, its a casting imperfection.

View Gene Howe's profile

Gene Howe

12183 posts in 4204 days

#3 posted 04-20-2018 07:16 PM

Third on the oxolic acid.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View Rich's profile


5619 posts in 1365 days

#4 posted 04-20-2018 07:23 PM

Fourth that (was third, but Gene got in before I finished typing…lol). Mix about a quarter cup in a quart of hot water and shake or stir to dissolve. You can make it stronger, but ultimately there will be undissolved powder left on the bottom. Brush it on to saturate the wood and leave it several hours or overnight. You’ll be left with a crystal coating on the wood that you rinse off with water. It will likely take multiple applications.

It’s a weak acid, but you should still avoid getting it on your skin or in your eyes. I like to mix it in mason jars so I can put a lid on the left over acid and store it for future use.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

View fivecodys's profile


1637 posts in 2411 days

#5 posted 04-20-2018 08:00 PM

You learn something everyday on this forum!

Way to go guys!

-- A bad day woodworking is still better than a good day working.

View Syellin's profile


9 posts in 1907 days

#6 posted 04-20-2018 08:29 PM

Amazing. I’ll give it a shot. Thank you

View Holt's profile


280 posts in 3404 days

#7 posted 04-20-2018 08:53 PM

Post an after shot, I’d like to see how well it works!!!!

-- ...Specialization is for insects.

View Rich's profile


5619 posts in 1365 days

#8 posted 04-20-2018 10:58 PM

Amazing. I ll give it a shot. Thank you

- Syellin

As I was thinking about this since posting. You might try using a container and setting the leg in there. It’s not that deep so you could use some deli type container or a tupperware type bowl. Let it soak an hour or so then dry overnight and rinse. I think you’ll get better penetration than just applying it with a brush.

When I use it I’m usually brushig it onto a flat surface where it can puddle and soak. That’d be hard to do on a vertical surface since it would just drip off.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

View AandCstyle's profile


3283 posts in 3032 days

#9 posted 04-21-2018 09:42 PM

Syellin, I would try cutting 1/8” or so off the legs to see how deeply the stain penetrated. It might be able to be sanded off.

-- Art

View Kazooman's profile


1492 posts in 2728 days

#10 posted 04-21-2018 10:17 PM

I am really intrigued to see how this turns out. That black “high water line” looks really intense, I guess the question is just how much the oxalic acid solution soak is going to affect the natural color of the piece. I agree, you need to set the legs in a container with the solution, brushing probably won’t provide enough juice to do the trick. Based on your pictures of the current state of affairs, I am thinking that by the time you get the black out, you will have some new problems to deal with.

Please post some pictures of your attempts to fix the problem, even if they fall short of success. We can all learn a lot from your problem.

One final (albeit “tongue- in-cheek”) thought is that the black feet actually look like a design element. If you can clean up the minimal stain I above the water line, you might have a winner.

View Ripper70's profile


1377 posts in 1684 days

#11 posted 04-21-2018 11:13 PM

While I certainly hope the oxalic acid method works for you, in the event that it doesn’t, there may be another solution rather than cutting the length of the legs down. A ferrule or sabot might be used to fit over the discolored area enough so that it would be unnoticeable. It’s hard to tell from the photos you posted how big the legs are but perhaps there are brass or some other metal sabots you could find that would fit.

-- "You know, I'm such a great driver, it's incomprehensible that they took my license away." --Vince Ricardo

View Kelly's profile


3010 posts in 3719 days

#12 posted 04-22-2018 03:25 AM

2,270 on the oxalic acid. It’s used on cedar fences to get rid of the iron stain from nails quite frequently.

Remember, the dust is nasty, so wear a respirator and collection when sanding.

View squazo's profile


173 posts in 2420 days

#13 posted 04-22-2018 11:24 AM

Wow I kind of like that tint of black. I might use that as a stain. I think you could sand it of. Think about refinishing a piece of furniture. How much sanding does that take? Not very much. Maybe a chemical stain/paint stripper. Please post pics whatever you do.

View bilyo's profile


1112 posts in 1878 days

#14 posted 04-22-2018 04:09 PM

There are some tongue-in-cheek comments above, which are humorous and true, about how good the rust stain looks. But seriously, in case you didn’t know, this method is sometimes used intentionally to stain oak and other wood that contains natural tannin. Simply fill a small container with white vinegar and soak some steel wool in it for two or three days. filter the liquid and use it like any stain or dye to achieve the effect. More details are readily available on-line: Youtube and other places.

View a1Jim's profile


118066 posts in 4352 days

#15 posted 04-22-2018 04:50 PM

Oxalic acid is a good suggestion but it still may not match the rest of the leg, if that’s the case think about using a contrasting wood or thin brass to make a band around the area that was blacked and make it a design element.


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