Applying HVAC Mastic to Air Seal Your Duct Work

Applying HVAC Mastic to the ductwork in the house to air seal the duct work in the attic. Mastic is easy to use, affordable, and can have a huge cost savings in the long run. More is better and this is not an item to skimp on.

[@lawrencemccoy]

Thanks for the info...

[@markkoons7488]

I'm putting together a 7-1/2 Hp wood shop dust collection system combining salvaged spiral and snaplock components. Since the runs will be suspended from a finished ceiling I intend to assemble all but the drops on the floor, well, the drops too, come to think of it. Things change in such an environment as processes and equipment change. I wonder whether mastic-sealed seams will be difficult to separate when an altered layout becomes necessary.

[@mytaborcityhome1002]

Once it’s dry it’s pretty tough. You can break the seal on it but it isn’t “easy “

[@michoacano-06]

hello I have a question after putting the mastic how long does it take to dry and turn on the air?

[@mytaborcityhome1002]

The drying time of the mastic is dependent upon humidity. But, a general rule of thumb is 48 to 72 hours.

[@michoacano-06]

thanks for answering.

[@diaperdood1]

Is it ok to put mastic inside the duct?

[@mytaborcityhome1002]

You can but it’s not necessary. Also, the mastic could cause turbulence inside the duct and be a point for duct and other products to build up on it. I wouldn’t do it.