Getting iron stain out of a finish (much like iron stain around a nail)

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Forum topic by BostonBowTie posted 07-02-2018 08:19 PM 2837 views 0 times favorited 6 replies Add to Favorites Watch
View BostonBowTie's profile


2 posts in 843 days

07-02-2018 08:19 PM

Topic tags/keywords: finish iron stain trick

How do I get an iron/steel stain out of wood? Like a nail stain, but on a finished surface.

I am almost finished with a set of oak bookshelves, To smooth out that bit or roughness in the finish, I gave it a brush rub with 0000 steel wool. Oh that made it nice and smooth. To wipe up the steel fines, I wiped up with a slightly damp paper towel. Oops, water, steel, and wood—not a good combination. An hour later, there was a black stain in the corner right around the joint – it looks like mildew

Here’s what it should look like:

Question 1. How can I get the black stain out without hurting the wood or the stain? The shelves are red oak, finished with Watco Danish Oil. Oxalic acid?

Question 2. Am I doing the right thing, giving a light rub with steel wool? It does genuinely feel smoother. I’m giving it a dry rub with the steel wool. Should I be using a lubricant or wax? (this is my first big project in several decades—my dad got this roll of steel wool in the 1970s) I don’t want a gloss, I just want to get the surface roughness out.

Thank you.!

6 replies so far

View bondogaposis's profile


5870 posts in 3231 days

#1 posted 07-02-2018 10:51 PM

Use wood bleach.

-- Bondo Gaposis

View Lazyman's profile


5860 posts in 2267 days

#2 posted 07-02-2018 11:11 PM

If it happened that fast it’s probably not very deep and you may be able to just use a card scraper to get it off the surface.

For future reference, I would use the synthetic “steel wool” you find with the finishing supplies or sandpaper. It is color coded and usually has the same rating as real steel wood (00-0000). This is a must if you are using a water based finish.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View bilyo's profile


1165 posts in 1982 days

#3 posted 07-03-2018 02:45 AM

The water and steel wool particles have made iron oxide that has gotten past your oil finish and reacted with tannin in the oak. This demonstrates the poor protection that an oil only finish provides. Oxalic acid should neutralize the stain almost immediately. Then you will probably want to put on another application of oil and then consider something more durable and protective over that.

View bd1886's profile


36 posts in 843 days

#4 posted 07-03-2018 05:13 AM

First post here! I’m a finishing restoration guy and all the advise here has been top notch. Oxalis acid is a godsend in bringing back the original appearance of freshness in wood stain by iron, aging, and non colorfast staining. (Follow manufacturer cautions, use due care….it’s acidic and while not super corrosive, the stuff needs used wisely.)
The only thing that I can add is oxalic acid needs neutralized either with a weaker acid (traditionally white vinegar) or OAN (Oxalic Acid Neutralizer). This makes for a hassle free finishing job and leaving no problems with encapsulating an “active” acidity in your finishing that can haunt an otherwise well done job down the road.
Well? Got my first posting out of the way and looking forward to getting some help where I need it….hope this helps some.

View CharlesNeil's profile


2501 posts in 4750 days

#5 posted 07-03-2018 01:47 PM

oxcylic acid
Wal mart sells it as wood bleach .

View waho6o9's profile


8946 posts in 3457 days

#6 posted 07-03-2018 02:02 PM

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