Q. I have three quartersawn yellow poplar boards that I am going to edge glue possibly using biscuits to make a 36-inch wide panel that will then be painted. What would be the best adhesive to join the boards? I was looking at an expensive crosslinking PVA because of its "waterproof" capabilities since I am applying a water-based wood primer. Will it creep? Should I use a resorcinol or the like. I have also read about using one of the polyurethane caulk-tube construction adhesives as well.
A. For panels that will not be wetted in service (except for a spilled cup or coffee, etc.) my first choice would be a medium-priced PVA with cross-linking. Waterproofing is not needed even with a WB primer, so why spend the money? I would also find that a medium priced PUR (not a cheaper one) would be OK.
PVAs do not creep unless they are under considerable stress, like a laminated beam. Also, note that biscuits help with alignment but not joint strength. Of course, you need to follow all the other correct gluing procedures including not too much pressure, not too large a joint gap (0.002 to 0.006 inch), freshly prepared surfaces, edges square and flat, etc. 
You didn't ask, but it is critical in my mind to apply the finish, especially a WB finish, to both sides equally and at the same time.


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Gene Wengert, aka The Wood Doctor, troubleshoots wood related problems, and explores lumber and veneer qualities and performance, species by species, in Wood Explorer, inside FDMC's Knowledge Center.


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