About BOSS Products

Informations about our construction products and our philosophy

BOSS® 353 Acrylic Gap Filler is a multipurpose, interior/exterior sealant that, when cured, forms a flexible, durable, weather resistant seal that bonds to most common building materials.

BOSS® 353 is fully paintable and sandable when cured. Uncured sealant cleans up easily with water. BOSS®353 will not bleed, stain or discolor.


  • Paintable
  • Sandable
  • Mildew Resistant
  • Non-Yellowing
  • Permanently Flexible
  • Weatherproofs / Waterproofs
  • Interior / Exterior Use
  • Water Clean Up


All surfaces should be clean and free of dirt, dust, debris, any oils and grease prior to application.

  1. Cut nozzle of cartridge to desired bead size and insert in standard cartridge gun
  2. Apply BOSS® 353 Acrylic Gap Filler into the joint
  3. Tool off excess sealant

BOSS® 353 Acrylic Gap Filler is packaged in plastic cartridges for use with standard cartridge gun and packaged 24 cartridges/carton.

Storage and Shelf Life

When stored in the original unopened container at or below 32°C BOSS® 353 Acrylic Gap Filler has a shelf life of 12 months from date of shipment. Containers should always be kept sealed when not in use.


BOSS 353 Acrylic Gap Filler