Yesterday the stacked heel joint on my latest build popped off under string pressure. The joint was glued up at the end of November using LMI glue (is there a trend here ...?) and the neck had been on the guitar/bouzouki under normal string tension for a couple of weeks before it popped. I had good squeeze out on the joint and it was done in a warm workshop at 45 degrees humidity. It could be I clamped too hard as the separation is clean and I can't see much trace of glue residue on either face - only at the outside edge, also I may not have left the clamps on long enough:
I am going to reglue but am biting the bullet and am preparing some hide glue from the granules I bought from LMI -first time use for me. I am going to follow Frank's recipie on the factsheet and his website, leaving it in the fridge overnight and then preparing some glue from the gelatine slab (with some scrap wood testing first of course!!).
My question to you hhg experts is what should I do to the surfaces of the joint? At present there is some very slight tearout of mahogany on the heel stack from the top neck piece, but the joint fits pretty perfectly with these, and as I say there appears to be clean wood elsewhere on both surfaces. Should I just join as is with the hhg, or sand the surfaces first after filling the missing mahogany with some slivers?
Also, the LMI instructions say not to use sterated sandpaper. I use 3M Tri-M-ite sandpaper - is this sterated or non-sterated sandpaper?
