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OSI HM-270 Ultra Silicone Sealant

OSI HM-270 Ultra Silicone Sealant

From: $12.75

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Ultra Silicone Sealant @12 Count

Colors Available: Clear, LG: Low Gloss 30° White

Sold By Tube Or 12 Count Box

SKU: 122 Category: Tags: , ,


OSI HM270 Construction Silicone Sealant is a medium modulus, one-part RTV silicone sealant designed for glazing and sealing. It cures at room temperature upon exposure to moisture in the air providing good tensile strength and excellent adhesion, usually without the use of a primer, to most nonporous building materials. OSI HM270 easily withstands temperature extremes from -60°F to 400°F without adverse effects. It is highly resistant to ultraviolet light and is virtually unaffected by other harsh environmental elements. OSI HM270 offers superior elasticity and long-life reliability. It forms a permanent watertight and weatherproof bond to materials like glass, ceramics, aluminum, primed steel and some plastics.

Recommended For:

HM270 is primarily used for structural or conventional type glazing and curtainwall sealing involving glass, plastic or metal.  Also good for sealing skylights, solar panels, ventilators, aluminum siding and windows, heating/air conditioning units, duct work, recreational vehicles and other glass, plastic or metal assemblies.

For Best Results:

Not recommended for the following applications:

  • Use with concrete, marble, brass, copper, oily woods, limestone, brick, lead surfaces, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) and other related materials
  • Joints subject to continuous water immersion (i.e. swimming pools, boats, etc)
  • Horizontal joints or traffic bearing joints where abrasion resistance is required (i.e. walkways, driveways, runways, etc)
  • Applications in totally confined or air-free spaces
  • Sealing green or vulcanized rubber
  • Use with potable water systems
  • Direct contact on the reflective coatings on mirrors
  • Applications requiring painting (paint will not adhere to silicone)


For a 10 fl. oz. (295 mL) cartridge:

  • A 1/4” (6 mm) bead extrudes approximately 31 ft. (9.5 m)
  • A 3/8” (9.5 mm) bead extrudes approximately 14 ft. (4.2 m)


Colors Available: Clear, LG: Low Gloss 30° White

Sold By Piece or 12 Count Box

Additional information


LG: Low Gloss 30° White, Clear

Pieces Or Boxes

Boxes, Pieces


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