Clamping Pressure For Wood Glue

Additionally consider how much the moisture in the wood will cause the wood of the joint to swell.

Clamping pressure for wood glue.

When those forces cause a failure it might not involve the original glue joint. During extensive research they undertook on gluing and clamping pressure the only manufacturer s reference the folks at lowell thomas tool found was on the titebond website. Too little pressure will fail to achieve any of these benefits. Dale zimmerman of franklin international maker of titebond woodworking glues recommends 100 to 150 pounds per square inch psi for clamping softwoods and 175 250 psi for hardwoods.

As the glued up piece goes through the normal expansion and contraction cycles in response to temperature and humidity changes the elevated forces you squeezed into the wood with excessive clamping pressure keeps trying to return the wood to its original shape. And fourth clamping holds parts in position until the glue cures. For softwoods pine poplar. The fine woodworking article also gave rough estimates of the average pressure various clamps are capable of producing.

Second as the glue releases moisture causing the wood to swell clamping overcomes this pressure and prevents the joint from opening up. In addition to getting the two pieces of wood close enough together for proper gluing pressure also squeezes out the excess adhesive and pushes the glue into the microscopic nooks and crannies. In some cases where adhesive is only on one of the mating surfaces pressure also assists in transfer of the adhesive to the other face. When we tested one handed bar clamps issue 139 we found that they provided pressure just into the softwood range or a bit less.