Description
ASI 502 silicone is a one-component, 100% RTV acetoxy silicone from American Sealants that cures to a durable, flexible silicone rubber. Manufacturers and installers use it as an industrial and construction grade sealant and adhesive for HVAC and ductwork, appliances and refrigeration, walk-in freezers, trailers, formed-in-place gaskets, and sink, faucet, and backsplash joints. It meets NSF Standard 51 for incidental food contact and is UL Recognized. As an acetoxy silicone it skins fast and releases a vinegar odor while it cures. It comes in 15 colors, seven standard and eight translucent, all in 10.2 oz cartridges. Made in the USA.
Key Product Details
| Property | Value |
|---|---|
| Chemistry | One-component 100% RTV acetoxy silicone, moisture cure |
| Colors | Standard: clear, white, black, gray, almond, aluminum, bronze Translucent: trans white, trans beige, trans gray, trans green, trans charcoal, trans rose, trans earth, trans blue |
| Viscosity (Spindle 7, 4 rpm) | 902,000 cps |
| Skin formation time (70°F, 50% RH) | 10 minutes |
| Typical cure rate | 24 hours (1/8 in bead) |
| Full strength | 7 days |
| Hardness (ASTM C661) | 25 Shore A |
| Tensile strength (ASTM D412) | 264 psi |
| Elongation at break (ASTM D412) | 500% |
| Joint movement | 25% (ASTM C920 Class 25) |
| Extrusion rate | 365 g/min |
| Density (ASTM D1475) | 8.5 lb/gal |
| Gun grade | Pass, non-slump |
| QUV weathering (ASTM G154) | Pass, 10,000 hours |
| Application temperature | -35°F to 150°F |
| Service temperature | -70°F to 400°F, intermittent to 450°F |
| Primer | Not normally required |
| Paintable | No |
| Approvals | ASTM C920 Class 25, Type S, Grade NS, Use NT, G, O TT-S-01543A TT-S-00230-C MIL 46106B Type 1 NSF Standard 51 FDA Regulation No. 21 CFR 177.2600 UL Recognized (File No. E209770) VOC compliant (23 g/L, ASTM D2369) |
| Shelf life | 12 months from date of shipment at 70°F and 50% RH |
| Package | 10.2 oz cartridge |
| Country of manufacture | USA |
Performance in Production
- ASI 502 passes ASI’s gun grade test as non-slump, so the bead stays put on vertical and overhead joints in ductwork, trailer walls, and backsplashes.
- It skins in about 10 minutes at 70°F and 50% RH. Tool the bead before the skin forms, and work in runs you can finish in that window.
- 25% joint movement (ASTM C920 Class 25) with 500% elongation at 25 Shore A gives a soft, stretchy rubber for joints that move with temperature and vibration.
- Service range runs from -70°F to 400°F, with intermittent exposure to 450°F, which covers walk-in freezers through heated equipment. It applies from -35°F to 150°F and extrudes easily in the cold.
- It passes 10,000 hours of QUV weathering to ASTM G154, so exterior joints hold up to UV and weather.
- A 1/8 in bead cures in about 24 hours, and strength keeps building for 7 days. Cold and low humidity slow the cure, and so does a confined joint.
- ASI 502 is an acetoxy silicone, so it releases a vinegar odor while it cures. ASI notes acetoxy can corrode sensitive metals when confined and isn’t suggested for long-term adhesion to concrete.
- It isn’t paintable. For joints that get painted, use a paintable sealant instead.
Common Applications
- HVAC and ductwork sealing
- Appliance manufacturing and refrigeration units
- Walk-in freezer manufacturing and installation
- Trailer sealing and RV and trailer formed-in-place gaskets
- Sheet metal work and sealing
- Sinks, drains, faucets, and countertop-to-backsplash joints
- Sanitary seals and plumbing
- Telecommunications sealing, including coaxial cable connectors
- Above-waterline marine sealing and fireplace manufacturing
Available Colors
Every color is the same ASI 502 formula with the same properties and approvals, in a 10.2 oz cartridge. The standard colors are clear plus six solid, opaque colors. Translucent colors let some of the surface show through the bead instead of covering the joint with a solid color, which suits sink, faucet, and backsplash work where a tinted bead fits the surface better. Pails and drums are available on request, so call us for bulk.
| Group | Color | SKU | Package |
|---|---|---|---|
| Standard | Clear | ASI-502-CLEAR-10C | 10.2 oz Cartridge |
| Standard | White | ASI-502-WHITE-10C | 10.2 oz Cartridge |
| Standard | Black | ASI-502-BLACK-10C | 10.2 oz Cartridge |
| Standard | Gray | ASI-502-GREY-10C | 10.2 oz Cartridge |
| Standard | Almond | ASI-502-ALMD-10C | 10.2 oz Cartridge |
| Standard | Aluminum | ASI-502-ALUM-10C | 10.2 oz Cartridge |
| Standard | Bronze | ASI-502-BRNZ-10C | 10.2 oz Cartridge |
| Translucent | Trans White | ASI-502-T/WHITE-10C | 10.2 oz Cartridge |
| Translucent | Trans Beige | ASI-502-T/BEIGE-10C | 10.2 oz Cartridge |
| Translucent | Trans Gray | ASI-502-T/GRAY-10C | 10.2 oz Cartridge |
| Translucent | Trans Green | ASI-502-T/GREEN-10C | 10.2 oz Cartridge |
| Translucent | Trans Charcoal | ASI-502-T/CHARC-10C | 10.2 oz Cartridge |
| Translucent | Trans Rose | ASI-502-T/ROSE-10C | 10.2 oz Cartridge |
| Translucent | Trans Earth | ASI-502-T/EARTH-10C | 10.2 oz Cartridge |
| Translucent | Trans Blue | ASI-502-T/BLUE-10C | 10.2 oz Cartridge |
Related Products
- ASI 502 100% RTV Silicone, 2.8 oz Squeeze Tubes for touch-up and small jobs without a caulking gun
- ASI 335 Neutral Cure Silicone for concrete, sensitive metals, and jobs where vinegar odor is a problem
- ASI 174 Paintable Siliconized Acrylic Latex for joints that get painted, such as countertop or backsplash to drywall
How to Apply ASI 502 Acetoxy Silicone
Applying ASI 502 comes down to a clean, dry, nonporous surface, a bead tooled before it skins, and a full day of cure. These are the steps from ASI’s data sheet. The same steps cover sink, faucet, and backsplash joints.
- Pick the color. For visible kitchen and bath joints, choose the standard or translucent color that suits the surface, and try it on an offcut first if the match matters.
- Check conditions. Apply between -35°F and 150°F. Heat and humidity speed up skin and cure. Cold and dry air slow them down.
- Clean the surfaces. Surfaces should be clean and dry. Wipe with 100% IPA or acetone depending on the substrate. Don’t use petroleum-based solvents.
- Skip porous masonry. Don’t use ASI 502 on porous surfaces such as concrete, mortar, or brick. Use a neutral cure silicone there.
- Test adhesion if you’re unsure. Primer isn’t normally required. Run a small trial bead and give it 7 days to reach full adhesion.
- Gun the bead. ASI 502 is ready to use with no mixing or additives.
- Tool before it skins. Finish tooling within about 10 minutes at 70°F and 50% RH.
- Let it cure. Allow about 24 hours for a 1/8 in bead before a sink goes into service or the joint sees water. Deep or confined joints take longer. Wait 7 days before testing strength or adhesion.
- Clean up. ASI recommends ASI 0240 Adhesive Remover & Cleaner for wet sealant. Dry sealant comes off by scraping or abrading with the help of ASI 0240.
Acetoxy vs Neutral Cure Silicone: Which One Do You Need?
Choose acetoxy silicone like ASI 502 when you need food grade compliance, a fast tack-free time, and high temperature resistance on common nonporous substrates. Choose a neutral cure silicone like ASI 335 for concrete, sensitive metals, a broader range of substrates, or jobs where the vinegar odor of an acetoxy cure is a problem. ASI’s silicone guide puts it this way:
- Acetoxy (ASI 502): bonds to common substrates, food grade available, faster tack-free time, resists high temperatures. It releases a vinegar odor, can corrode sensitive metals when confined, isn’t suggested for long-term adhesion to concrete, and has a narrower adhesion range.
- Neutral cure (ASI 335): low odor, broader adhesion range, adhesion to concrete, non-corrosive to most metals, resistant to oils and some chemicals. It isn’t food grade.
- Both: 100% RTV silicone, flexible across a wide temperature range, weather and UV resistant, solvent free, and not paintable.
Frequently Asked Questions
What is ASI 502 silicone used for?
ASI 502 is used to seal and bond HVAC ductwork, appliances, refrigeration units, walk-in freezers, trailers, sheet metal, formed-in-place gaskets, plumbing, and sink, faucet, and countertop-to-backsplash joints. ASI rates it as an industrial and construction grade sealant and adhesive for both interior and exterior work.
Is ASI 502 food safe?
ASI 502 meets NSF Standard 51 and FDA Regulation No. 21 CFR 177.2600, and ASI’s data sheet says it’s acceptable as a sealant on surfaces with incidental food contact.
What colors does ASI 502 come in?
ASI 502 comes in 15 colors. The standard colors are clear, white, black, gray, almond, aluminum, and bronze. The translucent colors are trans white, trans beige, trans gray, trans green, trans charcoal, trans rose, trans earth, and trans blue. All come in 10.2 oz cartridges, and ASI 502 also comes in 2.8 oz squeeze tubes. It’s made in the USA by American Sealants.
Is ASI 502 acetoxy or neutral cure silicone?
ASI 502 is an acetoxy cure silicone. It releases a vinegar odor while it cures and skins in about 10 minutes. For concrete, sensitive metals, or low-odor jobs, ASI makes a neutral cure silicone, ASI 335.
Can you paint over ASI 502 silicone?
No. ASI 502 isn’t paintable. For joints that get painted, such as a backsplash meeting a painted wall, use a paintable sealant like ASI 174 siliconized acrylic latex.
How long does ASI 502 take to cure?
ASI 502 skins in about 10 minutes and cures in about 24 hours for a 1/8 in bead at 70°F and 50% RH. Strength keeps building for 7 days. Cold, dry air and confined joints slow the cure.
What temperature can ASI 502 withstand?
Once cured, ASI 502 handles -70°F to 400°F, with intermittent exposure up to 450°F. It can be applied from -35°F to 150°F.
Can ASI 502 be used on concrete, brick, or granite?
Not on concrete or brick. ASI doesn’t recommend ASI 502 on porous surfaces such as concrete, mortar, or brick, and a neutral cure silicone such as ASI 335 is the better fit there. Granite isn’t on ASI’s current substrate list, though marble, porcelain, tile, and solid surface countertops are, so test a trial bead for 7 days or call us before sealing a granite top.
Questions on fit or color for your joint? Call (800) 220-1966 or email [email protected].
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