Raised Glue Joints after Staining
Before finishing I noticed some raised glue joints and sanded them smooth. I also noticed some glue joints that looked like an earthquake took place and filled them. Then I noticed that when I put my dye stain on, cut with acetone, it raised the glue joints again. I tried cutting with a weaker solvent, xylene based - same result. Then I tried denatured alcohol to cut it - same result.
Anyone know what is causing this? Anyone know what the cure is? I think my only option is to build them up with polyester and then sand smooth and put my topcoat on.
From Professor Gene Wengert, Sawing and Drying Forum technical advisor:
The UV cured adhesives are usually more stable and would not move or allow the wood to move, even with a solvent. But I am not sure how such an adhesive would work when fastening planks. How does the UV penetrate the joint to reach the adhesive in the interior to get it to cure?
So, what is causing the surface to swell, creating pressure which results in the raised joint? Or causing the core to shrink and getting the same effect? Why not try a panel that is wetted briefly with a damp rag? That will swell the surface, but not affect the adhesive.
Because alcohol is NGR and would not cause swelling of the wood, perhaps the environment is too humid and this is what is causing the swelling. Try some panels that you handle the same way as a stained panel, but do not dye or stain itů Just expose it to the same conditions. Finally, take a chisel and drive it along a joint lengthwise. Does the glue joint fail or is there wood failure? Is the wood failure only at the surface?
All in all, it sounds like wood movement issues, with the glue being flexible enough (or perhaps not a strong enough joint) to offer no resistance to wood movement.
Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?
Have you reviewed the related Knowledge Base areas below?