ASI 502 (UL, NSF Recognized)

100% RTV Silicone

ASI 502 is a 100% RTV Silicone that is UL & NSF Recognized.  ASI 502 is a one-part, moisture-curing RTV (room temperature vulcanizing) silicone that cures to a strong, silicone rubber that maintains long-term durability and flexibility. ASI 502 100% RTV Silicone is a non-slump sealant and can be applied to vertical or overhead surfaces without flowing or sagging. Because ASI 502 is a 100% RTV silicone sealant, it has excellent resistance to weathering including ozone, ultra-violet radiation, freeze-thaw conditions and airborne chemicals.

Fully cured, ASI 502 has excellent adhesion to glass, metal, porcelain, ceramic, wood, most plastics and many other nonporous substrates.

ASI 100% RTV Silicone (ASI 502) can be applied to surface temperatures from -18°C to +50°C (0°F to +120°F) and after curing, withstands constant operating temperatures from -70 to +400 degrees F.

Typical Uses

ASI 502 is an excellent sealant and/or adhesive for many industrial applications where a long-term, permanently flexible bond or seal is required. Such applications include:

  • formed-in-place gaskets for axle housings, differentials, junction box covers, etc.
  • adhering appliance trim and sealing appliance parts
  • adhering name plates, letters and signs
  • sealing joints in ductwork
  • sealing truck trailers, cabs, marine portholes and cabins
  • sheet metal
  • skylights
  • Sealing aquariums

General Sealing: Food service installations, walk-in refrigerators, trailers, engine components, seal and waterproof, coaxial cable connectors, weatherize switch parts and instrument mountings.


ASI 502 (ASI 100% RTV Silicone) is ready to use and requires no mixing or additives. The cure mechanism begins as soon as the sealant comes in contact with the air.

At conditions of 25°C(77°F) and 50% relative humidity, the sealant will skin in 10 minutes and fully cure in 24 hours (1/8 bead) and reaches its maximum adhesion in 7 days. Higher humidity accelerates cure. Tooling, if necessary, should be done before skinning takes place.

In applications where partial or total confinement of sealant is prevalent, the time required for proper cure is generally lengthened by the degree of confinement.

Surface Preparation

All surfaces should be clean and dry. It is recommended that bonding surfaces be solvent wiped with naphthas, ketones or chlorinated solvents. Specific solvents would include xylol, toluol and mineral spirits.

In case of plastics, determine suitability of solvent prior to use. Allow surface to dry thoroughly before applying sealant. Do not solvent wipe with alcohols or oil-containing solvents such as Varsol.


Priming for ASI 502 is not normally required for applications to nonporous surfaces.

Unprimed adhesion can be easily tested by applying a small trial bead and allowing 7 days for maximum adhesion to occur. If primer is required, contact ASI.


ASI 502 sealant should not be applied to surfaces that will be painted. Painting over sealant is not recommended because the paint film does not stretch with the extension of the sealant.

FDA Status

ASI 502 (ASI 100% RTV Silicone) is permitted under regulations of the Food and Drug Administration where incidental food contact might be involved. FDA Regulation number is 175.105.

About American Sealants, Inc.

Since 1987 American Sealants has become a recognized and trusted manufacturer, supplier and packager for some of the biggest brand name adhesive and industrial companies in the United States. American Sealants Inc. has grown due to its manufacturing capabilities, core values, and quality control processes. As a leader in the industry, our experienced customer service and technical team are here to ensure your satisfaction. You can be assured that you are receiving a quality product. We do not cut corners to provide cost savings – rather we offer a high performing product at a competitive price through our capabilities and processes. If you do not see something listed on our website, please do not hesitate to call and ask. With our experience we can help you get moving in the right direction.