I pretty much have a habit of leaving everything clamped up overnight in conditioned space that is ideally 72/50, or 72 degrees at 50% relative humidity.
So, for somewhat less than ideal conditions you adjust a little bit.
I worked in a stair shop for about six months and they would take flat panels out of clamps after an hour and run them through the Timesaver.
I don't hold with that but that is a feeling and it doesn't reference anything empirical.
When running my own cabinet shop I never took things out of clamps unless they had sat overnight. That was in the day of mortice and tenon joinery without additional mechanical help.
When I switched to using pocket screws as a hidden helper on the joints I would take the clamps off immediately. I know longer feel that is appropriate for things like doors that will enjoy hig stress during their lives. It seems to me that they need to sit in situ until the chemistry is complete enough to give them the maximum chance of survival.
Many of the glue bottles suggest a clamp time of from 30 minutes to 60 minutes.
It seems to me that a complex glue up, like a dowelled chair, where you are 'encouraging' imperfect fits to do your bidding have needs greater than this.
Once again, this is a matter of feel and not backed by data.
I've checked my Hoadley and looked at Forest Products Laboratory but I'm not finding the definitive stuff that I am looking for.
What I'm interested in is things like shear strength v. time and tension strength v. time for the typical PVA and A resin glues that we all use.
If someone can point me to data on this, it would be much appreciated.
Tom Watson http://home.comcast.net/~tjwatson1 /