Need help removing stain

hiriggs · Post by **hiriggs** » Sun Dec 02, 2007 3:10 pm

Accidentally allowed black pipe to stay in contact with workpiece being glued and have wide black line across project. Any ideas for removing stain?

a1gutterman · Post by **a1gutterman** » Mon Dec 03, 2007 12:45 am

Maybe others know better, but good old elbow grease with a little sandpaper is one answer.

berry · Post by **berry** » Mon Dec 03, 2007 8:45 am

A couple of thoughts. You didn't say if this is a flat panel or some sub-assembly for a larger project or even a final assembly? But...

Can the piece be reversed? I'm sure this must be blasphemous to some, but personally a defect that can't be seen in normal use, isn't a problem for me. It's kinda like the 'tree falling in the woods' it may fall but I've never heard it.

In addition to sandpaper paper you can remove a lot of material with a plane or a finer tool is a cabinet scraper.

Bleaching is another process. I've never used it but I know people who have - although they were doing a whole project like a floor not fixing one area.

And finally can you hide it with stain when finishing?

I have more than my share screw-ups in the shop and can imagine your frustration. Good luck.

Ed in Tampa · Post by **Ed in Tampa** » Mon Dec 03, 2007 9:58 am

hiriggs wrote:Accidentally allowed black pipe to stay in contact with workpiece being glued and have wide black line across project. Any ideas for removing stain?

Hiriggs
The mark could be one of two things or even a combination. Most black pipe is painted so the black may simply be some paint and practically anything like Acetone, Lacquer thinner, Naptha, paint thinner will take it off.

The other possibility is the mark is iron oxide stain formed when the water in the glue reacted with the iron in the bar. I would try a little Acetone or Lacquer thinner and see what that does. If the mark is still there then you have a choice, sanding or possibly bleach.

However test the bleach on a scrap piece of wood since some woods react to bleach differently.

In any case once you get the mark removed do a light sanding to remove any wood fibers you may have raised in the stain removal process and keep working.
Ed

Nick · Post by **Nick** » Mon Dec 03, 2007 2:32 pm

The iron in the pipe, the water in the glue, and the tannic acid in the wood all react together to create the black stain. The depth of the stain will depend on the type of wood. Generally the more "open" the grain, the deeper the stain. Woods like oak and walnut have an open grain (visible pores); cherry and maple have closed grain (microsopic pores).

You should not attempt to bleach out the stain. The same chemicals that remove the stain will also remove the "extractives" from the wood. Extratives are the chemicals that give a species of wood it's distinctive color. Instead, you will either have to plane, sand, or scape the stain from the effected area. I suggest getting a set of wood scrapers and learning to use them -- you'll be glad you did. See page 83 of "Sanding and Planing" or page 263 of "Woodworking Wisdom," both by Nick Engler.

With all good wishes,

charlese · Post by **charlese** » Mon Dec 03, 2007 9:46 pm

hiriggs - hope you weren't close to the finished dimension on that stained wood. The best luck I've had in removing such stains is to plane or sand them off. Also, I have simply made sure the stain was on the un-seen part of a table. I use oak for most furniture projects. Most of the time such stains occur on large flat pieces like table tops or glued up sides. If the piece is stained on one side only - you can use the un-stained side as the showing face. Hopefully the grain is well matched on this side.

Yes, I'm a little slow to learn that When using pipe clamps - put a piece of paper between the joint and the pipe. Waxed paper is best here, but any paper will work. There is no problem removing paper. No stain is always better than "stain removal".

curiousgeorge · Post by **curiousgeorge** » Tue Dec 04, 2007 12:37 am

Next time try sticking a strip of masking tape down the side of the pipe that may touch your project. It works for me.

psargeant · Post by **psargeant** » Tue Dec 04, 2007 7:59 am

This has been a problem for many of my woodworking friends and like every thing else is better prevented than cured. For those who are just beginning to assemble their pipe clamp collection, I would suggest purchasing galvanized pipe instead of black pipe. I know it is more expensive but I have never had the leaching problem that I have had with black pipe. The cost can be significantly reduced by purchasing 10 foot lengths and having a machine shop cut and thread them to your specifications. Another prevention is to purchase PVC pipe and make sleeves of it that slide over the black pipe that prevent wood-to-pipe contact. If the PVC is too tight one can cut a slit lengthwise in it that will relieve radial tension and allow it to be slid over the black pipe. It is not necessary to have a sleeve the same length as the clamp; only of sufficient length to keep the black pipe from contacting the wood. Another thing that works well is to use painters tape along the edge of the pipe-wood interface. The advantage of this to masking tape is the ease with which it is removed afterwards although sometimes adhesion to the pipe is a problem and masking tape works best.

Sarge