Last autumn, after the pine T&G paneling in our library had been on the walls for a while, we decided to give the boards a dark stain. Then the boards started to shrink in the dry winter air. By the following spring, many of the boards had a noticeably blond stripe between them. I solved the problem with a glue injector.
By drawing a full measure of stain into the injector (see drawing), I was able to deliver a thin line of liquid right where it was needed. The width of the line can be controlled by the speed at which you move the injector and the pressure you apply to the plunger. The injector I used was a 1/2-oz. polyethylene syringe with a 1-in. spout. I expect you can get them from just about any woodworkers supply shop or catalog. The one I used came from Leichtung Workshops (www.leichtung.com).
Paul Klein, Head Waters, VA