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Wanut Veneer Issues: Black Fingerprints

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Forum topic by Jermwood posted 07-12-2018 07:17 PM 702 views 0 times favorited 7 replies Add to Favorites Watch
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Jermwood

4 posts in 3 days


07-12-2018 07:17 PM

Topic tags/keywords: walnut veneer black fingerprints veneering oxidation question

So this is my first post here on the forum. I am a woodworker professionally but I’m experiencing
this issue for the first time.

My question is has anyone out there worked with walnut veneer and had to deal with the issue of black fingerprints on the veneer it self? I’ve experienced walnut and oak turning my hands black many times but not the actual wood or veneer itself.

I just moved from CA to Texas. This is my first time working with walnut veneer in this climate. I suspect it has something to do with the humidity. Any knowledge out there that can shine some light on how to deal with this. I’m pretty sure it’ll sand out but with a thin commercial veneer such as this there’s only so much sanding that can be done and I have to handle these quite a bit.

Has anyone out there had this same experience? If so how do you deal with it?

Thanks

-- iMake


7 replies so far

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John Smith

1102 posts in 212 days


#1 posted 07-12-2018 09:35 PM

Jerm – what did you handle before touching the veneer ?
does it leave fingerprints every time you touch it, or just one time.
photos of your concerns may help the gallery help you.

.

.

-- Graduated Valedictorian from the University of HardKnocks --

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LesB

1770 posts in 3492 days


#2 posted 07-12-2018 09:44 PM

It sounds like some iron or steel filings or fine power were on the fingers. it is the tanic acid reacting with your hands that turns them black and so it must be reacting to something that was on your fingers.

Rather than sanding I would try to bleach the black out and then touch it up with stain to blend the color back in.

-- Les B, Oregon

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Jermwood

4 posts in 3 days


#3 posted 07-12-2018 10:48 PM

So here’s Some pics of whats happening…
 photo IMG_8984_zps0rwlmpww.jpg

 photo IMG_8983_zps8vfglcrw.jpg

-- iMake

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Jermwood

4 posts in 3 days


#4 posted 07-12-2018 11:06 PM

Jerm – what did you handle before touching the veneer ?
does it leave fingerprints every time you touch it, or just one time.
photos of your concerns may help the gallery help you.

John, before I started working on this veneer I was working on a project with red oak solid wood.

_It sounds like some iron or steel filings or fine power were on the fingers. it is the tanic acid reacting with your hands that turns them black and so it must be reacting to something that was on your fingers.

Rather than sanding I would try to bleach the black out and then touch it up with stain to blend the color back in._

Les, No go on the bleach and stain solution. Client wants clear lacquer. But you may be on to something with the steel being the cause. A couple weeks ago I was grinding a lot of steel and doing some welding in the shop. I cleaned up really good but there could be some fine particles still around. Nothing that I can see though, so its not metal dust that is leaving the marks it’s definitely a tannin reaction. What is weird to me is that its transferring to the veneer. This happened yesterday and the marks sanded right out. Today I was experiencing the same thing with clean washed hands so I put on nitrile gloves while I handled the veneer. Also I should mention my forearms would make marks as well. Its pretty hot so I’m sweating while I work. Seems like the sweat might be involved with the reaction as well.

What do you guys think? Have you had this happen? I’ve only had hardwood tannins turn my hands black. Not my hands turn the wood black.

Thoughts?

-- iMake

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Andybb

1060 posts in 653 days


#5 posted 07-12-2018 11:53 PM

How about rubbing with denatured alcohol on a cotton rag??

-- Andy - Seattle USA

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Jermwood

4 posts in 3 days


#6 posted 07-13-2018 12:32 AM

How about rubbing with denatured alcohol on a cotton rag??

—Andy – Seattle USA

Wasn’t bad enough for me to want to use chemicals, sanding takes care of it fine. I’m more interested to know why this is happening and if anyone has had the same experience as me.

-- iMake

View enazle's profile

enazle

48 posts in 57 days


#7 posted 07-13-2018 04:56 AM

Yep, Robert Shaw’s factory was and still is in Fort Worth, sweat and taco bones are the biggest cause. The oils from your hand while pushing the piece through a saw can create havoc in the finish shop. Just sand it with 150 grit lightly before you finish it and you will be fine. I myself, sweat like a dog so I would wear gloves when ever working with White Oak or any kind of walnut.

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