On 5 Jun, 09:58, Stuart Noble wrote:

For glue, you need something with high initial tack and strong shear
resistance. Titebond is good. PVA isn't.

Pva is fine. Commercial framers don't use glue at all but rely on the
underpinner for fixing.

PVA has low shear resistance while wet, so it's harder to get the
clamps onto it without it going squiffy.