Four Categories Of HVAC Duct Sealants
The smooth consistency of water base
mastic products are safe,
non-flammable, and are easily
applied by brush or caulking gun. Additional
seal strength may be achieved through
the use of a scrim or polyester reinforcing
mesh that is embedded between two
layers of mastic. A variation of this product type is manufactured with polyester reinforcing fibers in the mix. This inherent feature provides additional strength to the mastic while dispersing evaporative solids (water) achieving shorter dry and cure time. Solvent base products in this category dry and cure as the solvents out gas.
Ambient weather conditions do not
effect dry and curing but, like
water base, dry and curing time
should be free of freezing temperatures. An additional type of solvent base sealant, known as seam sealant is commonly in use by sheet metal duct manufacturers to automatically seal longitudinal joints. It is injected into the transverse seam pocket as duct sections pass through the manufacturing coil line. This non-curing sealant remains in the seam pocket allowing sections of duct to resist leakage normally caused during transportation.
Caulked-in-place / Brush-on
Mastic Sealant