How to Apply Mastic Sealant or Foam Insulation Sealant

Mastic Sealant

• 1

  Put on safety goggles and work gloves. Brush dust from the area to be sealed using a dry paint brush.

• 2

  Cut the tip of the nozzle on the sealant tube. Use a sharp work knife and cut at a slight angle.

• 3

  Insert the sealant tube into the sealant gun. Aim the gun away from the seam you will be working on and gently squeeze the handle until the sealant appears at the tip.

• 4

  Place the tip of the sealant just above the seam you are sealing. Squeeze the handle of the gun gently and slowly move it along the seam to apply an even layer of sealant.

• 5

  Dampen a clean rag and gently run it across the seam to smooth out the sealant.  Allow the sealant to cure completely before disturbing.

Foam Insulation Sealant

• 6

  Put on safety goggles and work gloves. Extinguish open flames. Assemble the nozzle on the foam insulation can, if applicable.

• 7

  Position the tip of the nozzle against the seam you are sealing with the foam insulation. Press the button on the canister to release the foam.

• 8

  Move slowly down the seam as you continue spraying. The foam will begin expanding immediately to fill the gap.

• 9

  Allow the foam insulation sealant to cure completely before painting, trimming off excess with a knife, or disturbing in other ways. This will usually take several hours -- the amount of time will be indicated on the product label.