As far as using Duct Mastic on an operational system. You would want the system shut down for a while. But the stuff we use here in the factory is normally good to go in 24hrs. I'm sure the label on the tube/bucket is your best friend though.
Last year when I was going to do this to my house there wasn't any in stores either. I bought it from the modular factory where I work. But when I was reading this thread I looked on home depot site and it lists a tube and a 1/2gal. bucket of air duct sealant. I think the stores are coming around to the fact they have to start carrying this stuff.
|