Tannin-metal stains on white oak bowl

[Michael Anderson]

Hi everyone. I recently finished a white oak bowl that I was really pleased with. Until I looked at it this morning in natural light. Stains (from the tannins reacting with my gouge metal) everywhere. Initially I thought it was because the white oak was starting to turn bad; however, when I really looked it over, most of the stains appeared to be in places where I touched the bowl during the turning/handling process. Aside from just being better, faster, and more careful, is there anything I can do to prevent this in the future? Unfortunately, I’ve already oiled/waxed this one, so salvation might be difficult.

 

[Lou Jacobs]

Beautiful bowl Michael! I don’t see the problem. Looks to me like a feature of the rays, mostly in the heartwood, no?, and I’d appreciate it. By the way, is that a bandage on your right foot? Turning barefoot? I hope you didn’t drop a gouge! ;-)

 

[hockenbery]

washing hands after grinding will help.

Lemon juice will remove the iron stain finger prints etc.
we keep a bottle of real lemon in the shop fridge.

just wipe it on the spots with a paper towel or cloth.

 

[Lou Jacobs]

Oh, now I see what you’re talking about. As Rosanne Rosannadana would say, Never mind!

 

[Michael Anderson]

Thanks Lou and Al. Lemons juice works wonders. I used it to clean up my hands afterward, and rubbed some on the wood, but I think I waited too long. For the next oak one, I’ll probably keep a jar at reach—great idea. Washing hands after grinding is a good idea too.

 

[Michael Anderson]

right foot? Turning barefoot? I hope you didn’t drop a gouge! ;-)

Yes it is, haha! Non-turning related. I do like to turn in sandals though (sometimes barefoot), but I try to be extra cautious where I place my gouges.

 

[Michael Anderson]

Related note, I do want to salvage the piece though. I like the form, but hate the stains, so I might lean into the reaction and apply some steel wool/vinegar solution. I need to remove the wax/oil first. Is mineral spirits the best way to go?

 

[Odie]

Related note, I do want to salvage the piece though. I like the form, but hate the stains, so I might lean into the reaction and apply some steel wool/vinegar solution. I need to remove the wax/oil first. Is mineral spirits the best way to go?

Michael.....you might want to reconsider using steel wool. There are other options, such as scotchbrite that don't have the drawbacks of using steel. I used to use steel wool on my bowls, but completely phased it out of my methods.

-----odie-----

 

[Daniel Henry]

Related note, I do want to salvage the piece though. I like the form, but hate the stains, so I might lean into the reaction and apply some steel wool/vinegar solution. I need to remove the wax/oil first. Is mineral spirits the best way to go?

For me, I would use VM&P Naphtha

 

[Clifton C]

Try ammonia fuming, I used the blue print ammonia, nasty stuff. Apparently household strength works, and, you won't have to strip the oil/wax.
As to the steel wool/vinegar, if you smear the sludge on a white piece of paper, and like what you see, that's good, I've seen greens, obviously rust color, grays and a few others. Here is a link to another discussion, note the clear vinegar, steel wool filtered out after a short "steep" (like tea).
#15

 

[Michael Anderson]

Thanks, all.

Odie, thanks for the suggestion. I only use steel wool for making the ebonizing solution. I used to use it like I would scotchbrite (purple scotchbrite is my go to!), but I would almost always see tiny little flecks of metal, especially in woods like oak. I agree 100%.

Daniel, thanks for the input—that seems like a better idea. I’ve used naphtha before, but not vm&p naphtha. Is it faster drying?

Clifton (do you go by Clifton or Cliff?) do you think fuming would mask the blotchiness? I REALLY like the idea of not having to strip the finish. I’ve never fumed wood before, but I understand the concept/process and am always excited to experiment. Thank you for the vinegar/steel wool info as well. I have a good bit of experience eve with it, but I enjoyed reading the discussion and definitely picked up some ways to refine the process.

 

[R Henrickson]

Try ammonia fuming, I used the blue print ammonia, nasty stuff. Apparently household strength works, and, you won't have to strip the oil/wax.

I do a lot of fuming (household ammonia) of white oak, but ALWAYS before putting any sort of finish on the wood. It *might* work, but would probably take a very long time, and the finish or its remnants could well yield irregular results. I rather doubt you could remove the present finish *uniformly* over the entire surface (e.g., end vs side grain). I would advise against fuming. I'd either leave it as it is, or sand the surface thoroughly and refinish it with a clear finish.

Looked back at your photos -- there is both sapwood and heartwood. Sapwood does not fume well, and can end up looking 'dirty'. I make sure when I fume that there is no sapwood. The contrast is greatly enhanced by fuming

 

[Daniel Henry]

Thanks, all.

Odie, thanks for the suggestion. I only use steel wool for making the ebonizing solution. I used to use it like I would scotchbrite (purple scotchbrite is my go to!), but I would almost always see tiny little flecks of metal, especially in woods like oak. I agree 100%.

Daniel, thanks for the input—that seems like a better idea. I’ve used naphtha before, but not vm&p naphtha. Is it faster drying?

Clifton (do you go by Clifton or Cliff?) do you think fuming would mask the blotchiness? I REALLY like the idea of not having to strip the finish. I’ve never fumed wood before, but I understand the concept/process and am always excited to experiment. Thank you for the vinegar/steel wool info as well. I have a good bit of experience eve with it, but I enjoyed reading the discussion and definitely picked up some ways to refine the process.

VM&P is much cleaner than just naphtha. It is 'water' clear and fast drying.

 

[Michael Anderson]

I rather doubt you could remove the present finish *uniformly* over the entire surface

Noted. I was/am slightly worried about that. My plan B, if the surface is still blotchy, is to use India ink. In the end, it’s a fun learning experience.

@R Henrickson that’s interesting about the sapwood looking dirty after fuming. I hadn’t thought about that. It is also a bit inconsistent with the ebonizing solution. I intentionally kept the sapwood for movement in the “clean” piece, but now it is what it is.

 

[R Henrickson]

Noted. I was/am slightly worried about that. My plan B, if the surface is still blotchy, is to use India ink. In the end, it’s a fun learning experience.

@R Henrickson that’s interesting about the sapwood looking dirty after fuming. I hadn’t thought about that. It is also a bit inconsistent with the ebonizing solution. I intentionally kept the sapwood for movement in the “clean” piece, but now it is what it is.

I'm not sure that 'dirty' is the best description of the result -- perhaps 'greyish' is better. But I tend to avoid fuming sapwood in combination with heartwood.

I like the sapwood on your piece -- a nice accent.

 

[Don Wattenhofer]

I have done 100s of green turned bowls in both red and white oak and never had an iron/tannin stain appear that was not already present in the wood. The likelihood is that iron was present in the wood somewhere below the stain, which will happen in a yard tree or a fence line tree. The tannin stains on your fingers will go away on their own after a day or 2 assuming you wash your hands regularly.

 

[Michael Anderson]

I did suspect that some of the staining was present in the wood before turning, but I’m sure these fingers didn’t help:

 

[Kevin Jesequel]

I’ve been turning some chestnut lately that reacts far worse than oak. No matter what I do there are iron stains on the wood after turning and lemon juice does not seem to touch it. I’ve been using Bar Keepers Friend during the final sanding process and it gets rid of the stains almost immediately. It’s the oxalic acid in it that does the work. I’ve tried using straight oxalic acid, but it does not make as smooth of a paste as BKF does. Before anyone gives me credit for this, I got the idea directly from Chris Ramsey’s website: https://turnedandcarved.com/tips/stains.html

 

[Michael Anderson]

@Kevin Jesequel thanks for the tip! I’ve never run into this issue before in a significant way (aside from cherry sapwood, oof), but it’s like this oak is on steroids haha. I have to go to Home Depot later today, so I’ll definitely grab some Bar Keepers. Good tutorial on Chris’ site—that black stain disappeared like magic.

 

[robo hippy]

I do keep the lemon juice handy in the shop. If you catch the metal stains as soon as you are done turning the piece, it comes off easily, like in seconds. If you don't and the piece dries, it may take several applications to get the metal stains out. Problem is that when the wood is dry, the lemon can bleach out the wood, so if you have some drip down the sides, you can get streaks. I have learned to wipe off my tools with the wet shavings before I present them to the wood, and I also wipe my hands in the wet shavings to remove any metal dust. This solves 90% of the metal stains I get.... I don't like freckles on my bowls....

robo hippy

 

[Monty Ivy]

Great tips in this thread. Filing away for future reference.

 

[Michael Anderson]

Monty, I agree! And also, I like the change back to Obi-Wan

Reed, good advice, as usual! The freckles can be a soul killer haha.

For the sake of the thread, I'm going to post the salvation progress pics here. I didn't get a photo of the stripped bowl, but VM&P Naphtha worked amazingly well. Wiped the bowl down 3 times, and it was nearly back to unfinished, or as close as possible without having to sand completely. I had a few bead features separating the body/foot, so sanding wasn't ideal (and I just didn't want to! haha). I just coated the exterior with Bar Keeper's Friend solution that Kevin recommended. We'll see what happens! (obviously this strays from the linked protocol, but it's all good)

 

[Leo Van Der Loo]

You are lucky it is White Oak Michael, I learned a lesson like you but it was a Red Oak bowl, green and slinging wet wood.

Wiping the lathe bed with my hands to get rid of the sap and shavings, and yes it turned everything blue and black, and of course with the open pores of Red Oak, it went in deep with no chance to get rid of that, though I tried the oxalic acid and the 2 part wood bleach, no dice, it did get treated with the steel wool vinegar and that worked just fine.

Just wiping over the wood when turning with wet or sweaty hand will get the staining, as I also did that to feel the shape of the wood while turning, now I know what not to do .

 

[Brian Gustin]

Just wiping over the wood when turning with wet or sweaty hand will get the staining, as I also did that to feel the shape of the wood while turning, now I know what not to do .

Learned that the hard way doing a flatwork project (end table in white oak) - summertime work, in a T-Shirt and leaned a sweaty arm on the board while doing finish sanding. Less than 15 minutes later, I had blue-black stains on the wood so had to do sanding job all over again.

 

[Michael Anderson]

Oh sheesh, Leo, those red oak pores are pretty unforgiving!

That was my same mistake—feeling the shape of the wood. I was also finger stabilizing the rim on the outside when I was turning it thin, which is why most of the stains are on the top half. And then the bottom was where I grabbed it out of the chuck. Lesson learned! Ha

 

[Rusty Nesmith]

Nice looking bowl.

 

[Michael Anderson]

Thanks a lot Rusty!

 

[Michael Anderson]

Update after treating the inside of the bowl with BKF, cleaning up with water, and letting dry overnight. It looks clean! Will apply finish tonight or tomorrow and know for sure. Here’s what it looked like this morning:

 

[Monty Ivy]

Quite the transformation.

 

[Michael Anderson]

Thanks Monty, I hope the oil doesn’t reveal any hidden surprises ha. But the vm&p naphtha did such a good job removing the previous finish that it’s not even that big of a deal.

 

[Richard Coers]

Wet oak takes its revenge out on me. Do a few hours of turning and my hands turn purple.

 

[Michael Anderson]

Same, Richard. I currently have the hands of a mechanic, even after the lemon juice scrub haha

 

[Don Wattenhofer]

Working with kiln dried red oak in building internal trim and cabinetry will stain your fingers black but turning oak I rarely get stained fingers since I am seldom touching the wood with my bare hands.

 

[Michael Anderson]

since I am seldom touching the wood with my bare hands.

That’s something I need to improve upon, for sure.

Applied an oil/wax finish earlier today, and it looks like everything is clean! Thank you all for the help and suggestions. This thread was highly educational! Here are a couple of pics of the same areas as the first photos. Nice comparison.

 

[Phil Hamel]

I turned a piece of wet birch the other day and the next morning it was covered in black stains. Now I know how and why. Good info in this thread!