Official Luthiers Forum!

I know this was discussed, but I cannot find the thread.
Today I bent a set of KOA. VERY EASY TO BEND. I wrapped it in craft paper
as I always do. Bent it on one of John Halls benders. Heating blacket and
stainless steel slats. (But wrapped in paper) and I have some green on both
sides. How do you get rid of it???

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Andy Z.
http://www.lazydogguitars.com

it should sand out...

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John Mayes
http://www.mayesluthier.com

Andy, this happens to me as well. And, John's advice works as well, too. Watch your thickness, and sand away. Here's something gleaned from Allied Lutherie's site:
"One tip I recall is that sometimes when bending sides you end up baking some of the wood's greenish extractives into them. To avoid this, you can soak the sides in water and replace the water from time to time until the water remains clear."

Hope this sheds some light.

Steve

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From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com

I've just spent the morning sanding out the green in some Tas blackwood sides. It does come out, but it takes a fair bit of elbow grease.

The good news is that the box for #2 is closed!

Andy, my cherry turned green, too. Scared me to death. But it did sand out.

Ron

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OLD MAN formerly (and formally) known as:

Ron Wisdom

Somewhere in the middle of Arkansas......

The issue of wood turning green has to do with steel reacting with the tannins in some woods. Species like Cherry and Maple are particularly susceptible to this. You can avoid it by wrapping the wood in aluminum foil, which will not react with the wood. That's why professional bending irons are made from aluminum....

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Another tip is to make sure you use a decent quality foil, some of the cheaper ones seem to be made of something else that reacts.

If you want to use paper wrap your slats in foil first then use your kraft paper.

craft parchment is not the parchment paper to use like from a hobby shop. Use bakers parchment, it is meant to get hot and not cause burns. To use the craft stuff as opposed to bakers paper is comparing apples and oranges. You won't need the foil it is overkill

I believe there is a misnomer here. We're not talking about "craft" paper, it is Kraft paper. It is like brown wrapping paper.

Ron

_________________
OLD MAN formerly (and formally) known as:

Ron Wisdom

Somewhere in the middle of Arkansas......

Merci Beaucoup!
Andy


I did use kraft paper....I guess the wrong type

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Andy Z.
http://www.lazydogguitars.com

Brown celouse is the base of Kraft paper. Like the brown paper bag stuff
john

I thought that the last time this came up the consensis was that it is the aluminium foil combined with excess water that was the cause, and that substituting kraft paper for the foil was the solution?

I had greening on both sides but more on the first side that I bent where I had used more water, both sides were wrapped in foil.

On KOA I use distilled water . I don't want to run a risk of greening. My set had to be stained to cover the green. I still atribute the greening to the Aluminium foil as I have a well and know there are no chemicals.
   
   John Hall

Aluminum cannot react with wood tanins. Absolutely not. Steel can. If the steel gets wet, the water can work its way through or around the paper and right to the wood. I believe the issue is with the iron in steel, which of course does not exist in aluminum. If aluminum were the culprit, nobody, StewMac or LMI et. al. would make their bending irons from it. Look elsewhere for the problem.

John, well water can be loaded with chemicals from the ground. Sulphur and other minerals are commonly found in well water. Iron can leach from pipes into well water or tap water. Distilled water is always the best bet, or highly filtered water.
Don Williams38802.7878009259

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

[QUOTE=Don Williams] Aluminum cannot react with wood tanins. Absolutely not.
[/QUOTE]

Why not?

clear as mud.

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Andy Z.
http://www.lazydogguitars.com

Ok, here's what's been happening to me:
I bend over an aluminum pipe.
Then, the bent sides are cooked / cooled on a galvanized steel form. Now, the only place I had any greening at all was in the waist, where the waist clamp was wrapped with aluminum foil.
I'm thinking if any greening should have occurred, it would be on the inside, where the sides were against the galvanized steel. None there. Only the waist area, against the aluminum.

Hmmmmm...

SK

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From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com

I think Don is right, pure aluminium will not react, but some of the cheaper foils I think have something else in them that does react, so I think it is all to do with the grade of the foil used.

That said a good insurance policy for woods like koa, is brown paper.

Ok, Russ, I'll try that.
But I'm guessing that you will tell me next that there's brown paper, and then there's brown paper.

Am I right?

Steve

_________________
From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com

[QUOTE=Hesh1956]Excuse me guys but would you please let me know what the heck kraft paper is? [/QUOTE]

I've been wondering the same thing, Hesh.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

[QUOTE=Todd Rose] [QUOTE=Hesh1956]Excuse me guys but would you please let me know what the heck kraft paper is? [/QUOTE]

I've been wondering the same thing, Hesh. [/QUOTE]

I always thought it was the stuff brown paper bags ( or, "sacks", depending on where you come from) are made of.

This is taken from the American Forest and Paper Association web site:



Kraft Paper

Kraft Paper is paper made essentially from wood pulp produced by a modified sulfate pulping process. The word kraft is from the German word for "strong." It is a comparatively coarse paper particularly noted for its strength, and in unbleached grades is primarily used as a wrapper or packaging material.

Kraft paper can be watermarked, striped, or calendered, and it has an acceptable surface for printing. Its natural unbleached color is brown but by the use of semibleached or fully bleached sulfate pulps it can be produced in lighter shades of brown, cream tints, and white.

The most recognizable use of kraft paper to consumers is the paper grocery sack. The self-opening sack (SOS), which stands on its own, is an American innovation that has been around since 1883. Paper sacks are made from a renewable resource and they can be reused several times for shopping, then be recycled at curbside or drop-off sites. Paper grocery sacks make excellent recycling containers at curbside for old newspapers, magazines, mixed paper and other recyclables.



Cheers,

Phil

Steve

I should add that I am basing this on over here, one of our supermarkets has an own brand called tesco value and the foil is cheap, but it rusts ! and stains wood, one I went to a better brand which was described as Aluminium foil, I haven't had a problem.

Is now a good time to tell you there are lots of types of brown paper !!

Hesh

The stuff from Stewmac is perfect, that is what I use.