3M
3M 8374 Gray Sprayable Seam Sealer 10.5 oz Cartridge – 5‑10 min Work, 24 hr Cure
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Hazardous material · Paste
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Ground freight only (UPS/FedEx). Cannot ship via Air, USPS, or to PO boxes. APO/FPO addresses excluded.
WARNING: Cancer & Reproductive Harm
California PROP65 WARNING: This product contains the following chemical(s) known to the State of California to cause birth defects or other reproductive harm. This product contains the following chemical(s) known to the State of California to cause
Tap for details → P65Warnings.ca.gov
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Overview
Built for the job.
3M™ MSP sprayable seam sealer is a gray high-performance, general-purpose seam sealer that can be caulked or sprayed. Our convenient, easy-to-apply sealer adheres well to all primed surfaces, except acrylic lacquer. It offers the convenience of allowing for painting almost immediately after being applied.
3M 08374 Sprayable Seam Sealer is a gray paste formulation supplied in a 10.5 fl-oz cartridge for spray application. It is designed to seal seams, gaps, and joints on automotive bodies before primer or topcoat, providing a flexible barrier that prevents moisture ingress and corrosion.
The sealer can be applied at a film thickness of 1.4 to 1.6 mil and cures in 5-10 minutes, enabling rapid return to shop flow. It is compatible with aluminum, bare metal, OEM panels, and primed substrates. The low VOC content (13 lb/gal) helps meet environmental regulations while delivering consistent coverage across the specified thickness range.
Use requires standard personal protective equipment: eye protection, chemical-resistant gloves, protective clothing, and a respirator when spraying. Ensure adequate ventilation to control exposure to identified hazards, including acute toxicity, aspiration risk, and skin/eye irritation.
Why Pros Choose 3M MMM
- Single component moisture-curing MSP seam sealer offers convenience and quality
- Sealer is formulated for automotive body joints
- Versatile application methods allow caulking or spraying
- Excellent adhesion works well with primed surfaces
- Fast curing allows for immediate painting
- A single component moisture-curing MSP seam sealer
- Designed for interior and exterior body joints
- Can be caulked or sprayed
- Adheres well to primed surfaces except acrylic lacquer
- Paintable immediately
How to Use
For bare metal, door hem flanges, door jambs, door skins, exterior seams and joints, floor pans, galvanized, general purpose, interior seams and joints, joint filling, rear body panels and rocker panels
- Clean and degrease the substrate (aluminum, bare metal, OEM primer) to remove oil, rust, and contaminants.
- Apply the sprayable seam sealer using a suitable air-spray gun. Maintain a steady pass and overlap passes for uniform coverage. One coat is typical; apply within the 5-10 minute window specified for optimal film formation.
Compatibility
Compatible substrates: Primed Surface.
Compatible paint systems: Lacquer, Acrylic.
Specifications
| Part No. | 8374 |
|---|---|
| Product Line | MMM |
| MFR Model | 08374 |
| Standard/Approvals | California PROP65 WARNING: This product contains the following chemical(s) known to the State of California to cause birth defects or other reproductive harm. This product contains the following chemical(s) known to the State of California to cause |
| Application | For bare metal, door hem flanges, door jambs, door skins, exterior seams and joints, floor pans, galvanized, general purpose, interior seams and joints, joint filling, rear body panels and rocker panels |
| Manufacturer | 3M Products |
| Alternate Part Number-1 | 60980031284 |
| UPC | 051135083741 |
| Brand | 3M™ |
| Maximum Sale Quantity | 6 |
| Maximum Sale Day | 7 |
| Applicable Materials | Bare Metal |
| Composition | 15 to 40% Limestone, 10 to 30% Inorganic Filler 2, 10 to 30% Silyl Terminated Polyether, 5 to 10% Non-Phthalate Plasticizer, 3 to 7% Calcium Carbonate, 1 to 5% Dibutyl Phthalate, 1 to 5% Hydrocarbons, C11-C12, isoalkanes, <2% aromatics, 1 to 5% N-Ethyl-P-Toluenesulfonamide, 1 to 5% Inorganic Filler 1, 0.1 to 2% Stearic Acid, 0.5 to 1.5% N-Me 2-Pryrrolidone, < 1% 1,2-Ethanediamine, N1-[3-(trimethoxysilyl)propyl], < 0.5% Quartz Silica |
| Application Time | 5 to 10 min |
| Paintable (Y/N) | Yes |
| Specific Gravity | 1.4 to 1.6 |
| Sprayable (Y/N) | Yes |
| Color | Gray |
| Flash Point | 144 deg F |
| Container Size (oz) | 10.5 |
| Container Type | Cartridge |
| Form | Paste |
| Temperature Rating (deg F) | -20 to 200 |
| Curing Time | 24 hr |
- VOC
- 13 lb/gal
- Substrate
- aluminum, bare metal, OEM, primer
About 3M
3M is a global leader in abrasives, masking, and body repair products. Trusted by OEM collision centers for high-performance prep and finishing solutions.
Frequently Asked Questions
What substrates are compatible with this seam sealer?
The product can be applied to aluminum, bare metal, OEM finishes, and primed surfaces.
What personal protective equipment is required when using this product?
Use eye protection, chemical-resistant gloves, protective clothing, and a respirator as recommended in the safety data sheet.
Documents & Safety
DANGER: This seam sealer contains chemicals that can cause serious health effects including cancer, reproductive harm, and organ damage. May cause severe eye damage and skin irritation. Required PPE: safety glasses or goggles, chemical-resistant gloves, protective clothing, and respiratory protection in poorly ventilated areas. Avoid breathing vapors and prevent skin/eye contact. Can be harmful if swallowed or inhaled. Always refer to the full SDS before use.
Why Buy from autofxmart
- Authorized distributor — authentic, factory-fresh stock.
- Fast US shipping — most orders ship within 1 business day.
- 30-day returns — buy with confidence.
- Pro-shop pricing — bulk discounts available on request.
- Expert support — questions? Email us at support@autofxmart.com.
How to apply
Steps
1Clean both surfaces to bare, dry substrate.
2Load the cartridge and fit the mixing nozzle.
3Apply an even bead (or clamp) where needed.
4Tool or smooth the joint before it skins over.
5Allow to cure fully before stressing or painting.
Specifications
Full data
Frequently asked
Good to know
3M Products MMM is compatible with Primed Surface. Always ensure the surface is properly cleaned, degreased, and sanded before application to achieve the strongest adhesion and a professional finish.
The curing time for 3M Products MMM is 24 hr. Drying and curing times may vary with temperature, humidity, and film thickness — always consult the Technical Data Sheet (TDS) for exact cycle conditions.
This listing ships 3M Products MMM in a 10.5 container. Check the autofxmart catalog for other sizes and bulk pricing.
Most in-stock orders for 3M Products MMM ship the same or next business day from our US warehouse. Expedited options are available at checkout. Freight-class items may require an additional 1–2 days for carrier pickup.
Yes. autofxmart is an authorized distributor of 3M Products. Every unit is factory-fresh, sealed, and backed by the manufacturer's standard warranty. If you have a concern, contact support@autofxmart.com and we will make it right.
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