Rainbow® Quick-Seal Expanding Foam from Rainbow Technology is a single-component polyurethane expanding sealing foam that can be used as an insulating sealant and for adhesive applications.

Apply this foam sealant product to block air infiltration, minimize outdoor noise, prevent pest infiltration, prohibit transmission of odor, minimize allergy irritants, and more.

Suitable for indoor and outdoor surfaces. Available in a 12 oz. (330 ml/340 g) pressurized aerosol can.

Safety Advisory Warning: Always use this product in a well-ventilated area, wear gloves and protective eyewear, and comply strictly with the safety warnings and recommendations on the back label.

If this chemical product is inhaled or ingested, contact your local poison control authority. If it gets in the eyes, immediately wash (irrigate) the eyes with lots of water, and get medical attention immediately. If this product comes into contact with unprotected skin, flush the affected area with water. Where there is evidence of skin irritation, get medical attention.

Product Specifications - Rainbow® Quick Seal Expanding Foam

• Rainbow® Quick-Seal Expanding Foam from Rainbow Technology is a one-component product, so it's the only step you need to fill, seal, and cure—no mixing of separate components required.

• The foam sealant is specially formulated with a polyurethane composition that cures at room temperature within minutes of dispensing, even when exposed to moisture present in the air. The formulation contains no solvents and will not dry out, crack, or shrink.

• Quick-Seal foam sealant is conveniently packaged in an easy-to-use aerosol can, preventing the mess and extra tools otherwise required by messy non-foam sealants.

• Unlike caulks and other non-foam sealants, Rainbow® Quick-Seal foam sealant expands—blooming to become multiple times the size of the unexposed polyurethane solution—upon dispensing to fill gaps, cracks, and holes.

• When cured, the foam sealant assumes the shape of the cavity and forms an air-tight seal that doesn't shrink, retaining its permanent sealing properties. Since it is semi-rigid in its cured form, it withstands expansion and contraction without pulling away, unlike conventional sealants.

• This expanding foam sealant serves two important functions: first, as a sealant, and second, as an insulation medium that protects surfaces against moisture and temperature extremes.

• The foam sealant sticks to most smooth and textured surfaces, including wood, metal, masonry, glass, and most plastics. It is cream-colored and can be sanded and/or painted/plastered over.

• Sticks and bonds to most surfaces to fill gaps, cracks, and other cavities.

• Rainbow® Quick-Seal foam sealant isn’t just another sealant product—it’s a versatile solution that significantly boosts jobsite efficiency. Each can of Rainbow Quick-Seal Expanding Foam contains 12 ounces of polyurethane solution, which, when dispensed, expands into nearly 4 gallons of cured foam, replacing up to 20 conventional caulk tubes. That means fewer heavy caulk cartridges and guns to haul, faster sealage of large gaps and cracks, and shorter cleanup times. So field crews can finish maintenance tasks in half the time.

Rainbow® Quick Seal Expanding Sealing Foam Applications

Utility Vaults & Manholes

With Rainbow® Quick Seal, you can create durable, water-resistant expanding foam seals that keep excess moisture and pests out of underground electrical or communication systems. The foam sealant is composed of polyurethane that cures into a closed-cell structure, equipping it with hydrophobic properties.

Cable Risers & Conduit Openings

Traditional sealants often fail to fill and properly seal irregular gaps and cracks around conduit or pipe entries. Instead, apply Rainbow® Quick Seal, our foam sealant. It has high adhesion properties, cures quickly, and utilizes specialized foam sealant technology to rapidly expand upon dispensing to fill in every inch of empty space. It's the ideal sealant for technicians sealing telecom or fiber optic enclosures during field installations.

Abandoned Gas or Pipe Lines

Our expandable sealing foam is a reliable solution for municipal, commercial, and industrial gas technicians to safely block or seal cracks in unused or decommissioned pipes. The foam sealant cures into a hard, rigid, gap-free plug, preventing any passage of air drafts, gas leaks, or contamination. Still, it's super lightweight, so it's easy to trim or remove if future access is needed.

Construction Gaps and Building Voids

Our foam sealant is excellent for filling in wall cut-outs, window joints, and structural gaps and cracks. It also serves to insulate walls, blocking out excess sound, air drafts, and moisture, making it ideal for contractors needing a waterproof expanding foam sealer that performs indoors and outdoors. Whether you need to fill in holes where pictures used to hang or fill cracks between baseboards and windows, this foam sealant is the perfect solution.

HVAC and Mechanical Systems

Good insulation is essential for HVAC technicians to help customers thwart drafts, energy loss, and vibration noise. Our expanding foam sealer is a fantastic multi-purpose product for any day on the job, whether you're filling gaps in windows around drafty A/C window units, duct seams and joints, vents, or piping wall cut-outs/penetrations.

The foam sealant maintains impressive flexibility without forming cracks to accommodate system movement while maintaining a strong, airtight seal.

Telecommunications & Electrical Equipment

Block insects, dust, and moisture from entering junction boxes, fiber optic vaults, and cable terminations through tiny cracks by filling them in with our Rainbow® Quick Seal foam sealant. You can quickly apply it to most telecommunications & electrical equipment to create clean, professional-grade seals, significantly reducing the number of maintenance calls to answer.