What's turning my hands black?

[James Taglienti]

I've been working with a lot of white oak the past few days and after a few hours, my hands and arms look like this. It's that purplish color - almost the same as when I get a lot of iron filings on my skin. But I haven't been sharpening today.

The black stuff gets on the oak and turns it purple, just like iron.

It happened last project I used this oak from the same sawyer.

Is this just some iron-rich oak? It was locally sawn...

If you have any ideas or suggestions please tell me. It's driving me crazy.

[Doug Shepard]

Tannin in the oak is the culprit. Oak is one of the worst but other woods have tannin and will produce the same skin staining.

[Darnell Hagen]

Tannins reacting to sweat, just like oak, pipe clamps, and glue. Walnut and to a lesser extent cherry does the same to me.

[James Taglienti]

I thought it might be something like that but I've never seen it so extreme before.
and i have been sweating.

thanks guys

[Jon van der Linden]

Oak galls were used in the past to produce iron gall inks. There's a lot of potential for stains and colour change in certain oaks.

[Tony Shea]

Wow, that's a first for me. I've never seen such an extreme case from working wood. That's interesting.

[Deane Allinson]

You can return the favor. Drops of sweat will leave purple stains on the wood too. Mahogany also has a lot of tanin. That is why white oak and mohogany and white oak will fume with amoninia.
Deane

[James Taglienti]

This particular oak i have right now is pretty brown to begin with. It is also loaded with minerals and stuff- it dulls my planes and feels gritty. It will be the last time I take oak out of that pile for sure.

I didn't even do very much sanding- honest!

[Mike Brady]

When I raise the grain on white oak before dyeing it, I have to use distilled water or the open pores will turn black. Don't ever use a bare metal clamp on white oak (I'm thinking about the ones made with plumbing pipe) unless you put something between the metal and the wood as a shield. You can get stubborn black stripes. Yes, my fingers are usually stained from just casual handling of white oak.

[Pedro Reyes]

If I remember correctly a few drops of lemon, or better yet lime, juice on your hands as you wash them, will get rid of the stains, just a note.

/p

[george wilson]

My hands do not cause rust,yet walnut turns my fingerprints purple too. Not the whole hand,though.

[Tony Shea]

This particular oak i have right now is pretty brown to begin with. It is also loaded with minerals and stuff- it dulls my planes and feels gritty. It will be the last time I take oak out of that pile for sure.


The last white oak that I just used to make some Krenov style saw horses was filled with some gritty substance that really did a number on my planes. I had to consistantly sharpen my plane blades, as well as my mortising chisel as they would not last long. This was some of the hardest wood for my tools I've ever dealt with, worse than the last batch of figured Bubinga I've used. I contributed the issue had to do with the grit that constantly showed up in the wood. But it was also some very dense oak. Probably would have made a decent wood plane without adding a sole. I will say that the surface really ended up incredibly smooth after finish planing it though. I used the smoother and rubbed a few shavings on it and had just a beautiful surface, but they are just saw horses anyways but furniture grade ones. I never did have trouble with any black staining though.

[Harlan Barnhart]

White oak always makes my hands black although not as dark or as pervasive as the opening post. And consistently chips the cutting edges of my chisels even with light chopping. I am considering buying some HSS chisels just for white oak since I like to use it to make exterior doors.

[Jamie Ray]

I've been told the salt content in sweat is actually what is reacting to the tanins. Hence, consuming less salt and drinking more water should reduce the problem. I can't say for sure that is true but when I laid off salt and started drinking only water (for health reasons) it seemed to reduce my reaction. I've even had walnut turn my hands purple. It really sucked when I left to work to deposit my paycheck. Working in a studio furniture business it seemed my hands were always purple or black and the tellers at the bank always gave me weird looks.

[Niels Cosman]

Walnut does it to me every time.
If i've been sanding a lot I even get a little purple mark on my nose underneath the bridge of my glasses. It freaked me out at first thinking it could be a sign of an allergy, but I figure it's the same as the way red wine stains the lips.