Titebond III stains...

[Joe]

Had a nasty surprise gluing some oak veneered pieces with Titebond III. Every place there was a contact with the cast iron clamp a jet black stain resulted. I thought it might be tannins in the wood, so tried just clamping a piece of pine to the cast iron with Titebond III at the interface, and sure enough, a black stain showed up there as well. There is apparently an adhesive to iron reaction going on, so henceforth, cast iron will be isolated from the Titebond in glue ups. Polyfilm should work OK, likely.

Joe

[cedarsonny]

I think it's the clamp, not the glue. Raise your clamps off the woodwork with shims/spacers. Same with C-clamps, use blocks/spacers between the clamp and the woodwork.

Sonny

[dadiOH]

The steel blackens because the glue is acidic. So is Titebond ll

[SonomaProducts.com]

very place there was a contact with the cast iron clamp a jet black stain r= esulted. I thought it might be tannins in the wood, so tried just clamping = a piece of pine to the cast iron with Titebond III at the interface, and su= re enough, a black stain showed up there as well. There is apparently an ad= hesive to iron reaction going on, so henceforth, cast iron will be isolated= from the Titebond in glue ups. Polyfilm should work OK, likely. Joe

I've learned this lesson... several times.

[Larry Jaques]

shims/spacers. Same with C-clamps, use blocks/spacers between the clamp and the woodwork.

cedarsonny, you should have also told him to wax his Johnson. Erm, I meant to say Johnson Wax his clamp pipes. It helps keep glue from sticking to them and keeps the pipes from marring your wood. I always rub my projects down with lacquer thinner before finishing, so any wax which might have rubbed onto the surface would come off, anyway.

Alternatively, wax paper works well, too.

-- Never trouble another for what you can do for yourself. -- Thomas Jefferson

[Richard]

Every place there was a contact with the cast iron clamp a jet black stain resulted.

I thought it might be tannins in the wood, so tried just clamping a piece of pine to

the cast iron with Titebond III at the interface, and sure enough, a black stain showed

up there as well. There is apparently an adhesive to iron reaction going on, so henceforth,

cast iron will be isolated from the Titebond in glue ups. Polyfilm should work OK, likely. Joe

You don't normally put blocks under your clamps??

[Puckdropper]

Joe wrote in news:1d2bb7e5-5191-4859-89e3- [e-mail]:

Long ago, I came across a tip to use pipe insulation on pipe clamps to keep the black coating from rubbing off (or to keep the metal from reacting.) It can be a bit of a hassle, but no more than any other method.

Puckdropper

[Dr. Deb]

That is one of the two reasons I never use black pipe, but always us ridgid (or thick walled) conduit. The other is, ridgid conduit is cheaper and, depending on how you cut it, you get your choice of the length of two clamps for the price of one piece of black pipe.

In case you are wondering, ridgid conduit works just as well as black pipe, after all, it is merely galvanized pipe that is used for electrical purposes.

Deb

[Leon]

Not terrribly complicated here, this will happen when water touches iron. Your glue is water based and it causes a reaction with the iron. This happens with most any wood glue that is water based.

[Mike M]

I to use rigid conduit but mainly because it was free as I worked as an electrician. The galvanizing be hard does make so the clamps don't grap the the pipe as well but they will grab. I also go thru a lot of wax paper.

Mike M

[whit3rd]

Oak and iron makes black stains; this can be cleaned up with an oxalic acid "wood bleach" solution. Keep it damp and the stain will dissolve, then rinse off. Keep the solution AWAY FROM ANY IRON ITEMS.

Oak gall and iron are the classical ingredients for nice black ink with ferrite nanoparticles.