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Forum topic by woodworm posted 03-23-2009 03:32 AM 1959 views 0 times favorited 15 replies Add to Favorites Watch
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woodworm

14164 posts in 3053 days


03-23-2009 03:32 AM

Topic tags/keywords: tip

Well, I think I should share my experience due to bad habbit ”in a hurry”. I was veneering a number of 2-1/2’ long frames for my hanging/wall cabinet. Due to hot weather maybe, I noticed the glue I had just applied to thin veneer strip was drying very fast. In a hurry and not wanting to wet it with water, I grabbed my 3’ steel ruler and used it as the clamping caul.

Can you guess what happen?
My veneer got smeared with blotchy black stains and is not removable. As shown in the pic below, you can see the different between the first one (using masking tape only) and the second one (using steel ruler as the clamping caul).

Can anyone explain what actually happened?
I guess when I clamped it with excessive presure, the glue penaterated through the thin veneer and contacted the steel ruler that caused an “oxidation” ( not sure I’m using the right term”).
What do you think?

So do not do work in a hurry and do not use bare steel for clamping veneer.
Thank you

-- masrol, kuala lumpur, MY.


15 replies so far

View marcb's profile

marcb

768 posts in 3136 days


#1 posted 03-23-2009 03:39 AM

I don’t know the exact science behind it but metal stains wood.

View Chris Wright's profile

Chris Wright

540 posts in 2944 days


#2 posted 03-23-2009 04:14 AM

Well, I know that wet steal with stain oaks. Wet steel and iron filings use to used as a wood stain for that purpose. Looks like a similar process occurred here.

-- "At its best, life is completely unpredictable." - Christopher Walken

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lew

11339 posts in 3218 days


#3 posted 03-23-2009 04:18 AM

This also happens when black iron pipe clamps come into contact with the glue. There is a chemical reaction between the metal, glue and wood.

Oak is especially susceptible to this type of staining but it happens with other woods as well. Sometimes the staining is not very deep and can be sanded out, other times you aren’t as lucky.

Lew

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View woodworm's profile

woodworm

14164 posts in 3053 days


#4 posted 03-23-2009 06:42 AM

Today I did make an experimental test on the effect of metal (steel) when in contact with wet wood.
I wet a piece of scrap wood with just plain water and another piece with glue and clamped both to my steel ruler.

I will let you know whether both have same or different results.

-- masrol, kuala lumpur, MY.

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woodworm

14164 posts in 3053 days


#5 posted 03-23-2009 11:40 AM

Here is the results :-

Looking at the pic above, the result is a bit surprising to me. The wood (top) was wet with glue and the other one (bottom) was wet with plain water. They were simultaneously clamped to the steel ruler for 4 hours.

-- masrol, kuala lumpur, MY.

View cabinetmaster's profile

cabinetmaster

10874 posts in 3021 days


#6 posted 03-23-2009 12:24 PM

Dave’s right…....... But very true….........do not get in a hurry. something always goes wrong when in a hurry.

-- Jerry--A man can never have enough tools or clamps

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woodworm

14164 posts in 3053 days


#7 posted 03-23-2009 12:35 PM

My assumption, water alone will not (as fast as glue or other chemical) cause steel to stain wood.
That’s why (maybe) finishers use to soak steel wool into vinegar-mixed water to make stain.

-- masrol, kuala lumpur, MY.

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woodworm

14164 posts in 3053 days


#8 posted 03-23-2009 12:43 PM

Dave, do you think it is more like fungus rather than stain?
Rolled steel? Can I use my clean scrapper as an alternative? I supposed so..I will try

-- masrol, kuala lumpur, MY.

View Treeclimber's profile

Treeclimber

9 posts in 2845 days


#9 posted 03-23-2009 01:30 PM

I’ve seen this reaction with wood many times both inside and out. Trees with “hardware” grown into them over the years perhaps from someone nailing a sign to a tree or a forgotten clothesline pully. I have found an old shotgun grown into the tree. The technical reason is soluble chlorides that are present in the wood can
form acidic conditions around steel in wet wood, and result in accelerated corrosion of the metal and weakening of the wood. Any one that has taken pallets apart to use the wood knows that sometimes those nails in contact with the wood are somewhat desintegrated leaving the immediate area stained. The wet glue has a similar reaction causing the metal to corrode and resulting in a stain the depending on the type of wood will travel within the porous cells as long as water and metal are in contact. As mentioned by others, oak has a lot of tannic acid and is extremely reactive with metal. There are also many different types of fungus that will cause staining (blue stain in pine and other softwoods) as well. Sorry for the long response but my wood chemistry is much better than my current woodworking skills. I lhope it answered some of your questions…

-- Allan

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woodworm

14164 posts in 3053 days


#10 posted 03-23-2009 05:11 PM

Marc, Chris Wright, Lew, Dave and Allan thank you for you time and participation in this forum, and also my thanks to all fellows LJs for viewing.
As suggested by Dave, I tried it with scraper card (non stainless steel) by wetting two pieces wood of the same species with glue and plain water to see wether they react differently when in contact with steel. I will post the result tomorrow.

Thank you everyone.

-- masrol, kuala lumpur, MY.

View HokieMojo's profile

HokieMojo

2103 posts in 3191 days


#11 posted 03-23-2009 06:18 PM

I’m pretty sure this should sand off relatively quickly. It ussually does when I get marks from my clamps.

View mmh's profile

mmh

3665 posts in 3185 days


#12 posted 03-23-2009 06:23 PM

Well, it looks like you’ve started the mineralize the wood with this technique. Another million years or two and you’ll have petrified wood, or maybe opalized?

-- "They who dream by day are cognizant of many things which escape those who dream only by night." ~ Edgar Allan Poe

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woodworm

14164 posts in 3053 days


#13 posted 03-23-2009 08:05 PM

HokieMojo, the answer is yes for the wood but if I were to sand the 1/32” thin veneer, I would have a bare frame.

-- masrol, kuala lumpur, MY.

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HokieMojo

2103 posts in 3191 days


#14 posted 03-23-2009 08:44 PM

good point. i didn’t think of how thin veneer can be.

View Ben Griffith's profile

Ben Griffith

50 posts in 3142 days


#15 posted 03-23-2009 11:09 PM

I think I’ve heard that oxalic acid will remove iron stains in wood, effectively reversing the ebonizing that happens when tannins in the wood react with iron.

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