03-25-2021, 10:02 AM
(03-24-2021, 07:36 PM)cputnam Wrote: I queried Titebond directly about TB III and John is correct. At 150°F, strength is less than the wood. Further, from [personal experience here in the arid Southwest, open time is somewhere between 1 and 2 minutes at 95°F and 15% RH. Liquid hide glue lasts about 4 - 5 minutes while I believe Weldwood is longer. Epoxy is still the best bet for a long open time and water resistance but even it wealens with heat.
Yes, that's correct; many epoxies lose strength at 150F, too. Both T-88 and West Systems epoxies have a creep temp. of about 120F and a max use temp. of 160F. In comparison, the max. use temp. of Gorilla Glue is 200F. In reality, West Systems epoxy has been used by boat builders for many years and it has proven itself to stand up against heat, so the tests used to determine performance properties appear to be more extreme than reality, which is a good thing to me. I've also had no failures with TB III used in exterior door or furniture joints, but I have seen it fail in glued up exterior door panels exposed to direct sun.
I measured the temperature on the surface of a wood exterior house door that had a storm door over it. It got up to over 180F when the sun shone on it, and that was in April. The owner would not let me remove the storm door, so to give my new wood door a fighting chance I used epoxy for all the joints, and I also vented the storm door and insisted he have 3M's heat/UV film installed on the glass. Three or four years later the door looks as good as the day I installed it.
John