My customers have been having a problem with the reformulation of Franklin’s polyurethane glue. In the Florida heat and humidity, the set time has been reduced from 30-40 minutes to 8-12 minutes. Franklin agrees there is a problem, but their attitude is basically, live with it. Any ideas on a poly glue for furniture building that can withstand the heat?
It's the humidity that's causing the glue to kick too soon, although the heat does intensify the problem.
Formulators tell me it's easy to change the reactivity of a polyurethane glue. Just tweak the ratios of the two or three base components.
Excel, at least at one time, was the slowest-acting polyurethane of all. Give it a try, and make sure the lumber is very dry before gluing up, so the only thing that's kicking the glue is the moisture in the atmosphere.
Our shop is climate-controlled year round for proper gluing and finishing conditions. We have humidification in winter and air conditioning with dehumidification in summer. Our goal in summer is to keep the shop below 80 degrees and under 60% humidity.