Replies

1. 
   UncleDunc | Jan 24, 2003 07:41pm | #1

   It's been reported in FWW several times. Water in the glue causes localized swelling, and if you sand or plane before the swelling goes down, then you get the dimples when the wood shrinks back to its equilibrium state. I've also seen reports of getting a valley along a glue line the same way.

1. 
   BrianW | Jan 24, 2003 09:13pm | #2

   Thank you for the information. How do you prevent this from happening again? Is it the moisture content or the species of the wood?

   Thanks, Brian

1. 
   HowardAcheson | Jan 24, 2003 10:36pm | #3

   The only way to deal with it is to let enough time go by that the moisture in the biscuit and surrounding wood has fully evaporated. Depending on how much adhesive you used, the humidity and temperature in your shop and the type of wood, it could be up the 4-5 days. Best thing to do is wait.

   Also, scraping and sanding glue lines too soon can be problematic. The water in the adhesive causes localized swelling at the joint. It the joint is sanded too soon, you flatten the joint which then sinks when the moisture is fully evaporated.

   It happens most in softer woods and woods less than 1" thick.

2. 
   UncleDunc | Jan 24, 2003 11:01pm | #4

   Or you could use a glue with no water in it, like urethane or epoxy.

1. 
   JayS | Jan 25, 2003 02:43am | #5

   Also, it mattters how thick the boards are.  If the biscuit is too close to the surface, it is more likely to show through.  I try to keep mine at least 1/4 inch and preferanly more, from the surface.