ASI 502 100% RTV Silicone Sealant, Clear, 10.2 oz Cartridge

The ASI 502 silicone sealant 10.2 oz cartridge is ASI’s High Performance 100% RTV Silicone in clear, packed for a standard caulking gun. It is the size for linear work, such as ductwork seams, walk-in freezer panels, countertop runs and sheet-metal laps, where a 2.8 oz tube would run out halfway. To be clear about the package: this is a caulking cartridge, not a squeeze tube, so you need a caulking gun to dispense it.

Key features

• Construction and industrial grade: ASTM C920 Class 25, Type S, Grade NS, Use NT, G, O; TT-S-01543A; TT-S-00230-C
• 25% joint movement capability for joints that expand and contract
• Listed by ASI for NSF Standard 51 and FDA 21 CFR 177.2600 (incidental food contact), UL Recognized and MIL 46106B Type 1
• Gun-grade, non-slump paste that ASI says extrudes easily in cold temperatures
• Skins in about 10 minutes; cures in about 24 hours per 1/8″ bead (70°F, 50% RH)
• 12-month shelf life from shipment when stored at 70°F and 50% RH

Where to use it

ASI names HVAC and ductwork, appliance manufacturing, refrigeration units, walk-in freezers, trailers, formed-in-place gaskets, sheet metal, countertops, kitchen and bath, sanitary seals and plumbing. A cartridge is the practical format for a technician sealing a run of duct joints, a facilities team resealing a commercial kitchen, or a shop assembling appliances or cabinets.

How to use

1. Remove old sealant, clean with 100% isopropyl alcohol or acetone, and let the joint dry. ASI warns against petroleum-based solvents.
2. Load the cartridge into a caulking gun, cut the nozzle to the joint width, and work between -35°F and 150°F.
3. Run the bead with steady trigger pressure so it fills the joint; on vertical or overhead joints the non-slump paste stays in place.
4. Tool within about 10 minutes, before skinning.
5. Allow about 24 hours per 1/8″ bead (deep or confined beads take longer) and check adhesion on day 7.

Compatibility and cautions

As an acetoxy silicone, ASI 502 is corrosive to sensitive metals when confined, according to ASI, so it is not for electronics. ASI also says not to use it on porous surfaces such as concrete, mortar or brick, and it is not paintable. Adhesion to plastics varies, so run a test bead. The acetic acid released during cure calls for ventilation; the SDS does not classify the product as hazardous under GHS. Heat and humidity shorten the 12-month shelf life, so store spare cartridges somewhere moderate. Documents: technical documents.

Choosing between tube and cartridge

For small repairs, the ASI 502 clear 2.8 oz squeeze tube is the same sealant without the gun; we also stock white and black 2.8 oz tubes. For electronics, the ASI 388 10.2 oz cartridge is the neutral-cure alternative, and for aquariums, the ASI 509 clear cartridge. Our acetoxy silicone guide covers when ASI 502 is the right call.