I just finished installing the plywood base and i am debating glue to install my mdf plenum. I am a flooring contractor and have urathane hardwood flooring glue avaliable. The main perk is that it is moisture cure allowing me to cut my plenum 6-8 hours later. The thing i am not sure about is that the glue has some flex to it. It gives a great hold i am just not sure about using it for this appliacation. The other option will be titebond 3 which is very rigid and full of moisture. if i use the wood glue i will be waiting 2-3 days before cutting the plenum, since i am in phoenix az which is normally dry but we have had rain for the past few days with more to come. I dont want the dry hot summer to come and have things warp.
Any comments or suggestions would be greatly appreciated.