In my last project, I was very conscientious about the removal of glue during the assembly process. I was also diligent about the presence of any glue during sanding. In spite of my efforts, when I applied stain, several glue spots became apparent. I tried to sand the specific spots but only created a larger area that doesn’t match the initial stain coat. What is the best way to remove the glue spots where the stain did not take without sanding the whole section of wood? How does one avoid the occasional errant glue spot?
Simon Watts: Your mistake is trying to sand glue spots. Don’t do that: use a scraper instead. If you don’t own a scraper, a piece of freshly broken window glass works almost as well. Masking areas not to be glued will save you much time and aggravation.
Michael Dresdner: There are actually several things you can do. First, let’s deal with the ones that you found. If you are using hide glue, you can get the spots off with warm water. With Titebond type glues, try scrubbing with a bit of Scotchbrite dipped in lacquer thinner. Then re-sand the area with the same type and grit sandpaper you used prior to sanding. This is very important. This will all help, but will not guarantee even re-staining. Some stains tend to blend, while others do not. The best bet is to avoid the problem.
The easiest glue to remove after glue-up is hide glue. The residue comes off with warm water and hide glue tends to accept both water and alcohol soluble dye. To see the spots before you stain, try wetting down the piece with the solvent for the stain. For example, the solvent for an oil-based stain is mineral spirits. Wetting the piece down with mineral spirits will usually make the glue spots stand out, though not as prominently as with stain. But if you look carefully, you can see them before you stain.
Finally, consider pre-finishing — finishing any parts that you can prior to glue-up. Adhesives don’t stick to finished wood very well, and you certainly won’t have glue spots if you stain before you glue up. It is astounding how many things can be pre-finished, and the few that can’t tend to be the ones that get so much sanding after glue-up that glue spots are not a problem.