3M
3M 8367 Black 1‑Component Seam Sealer 310 mL Dual Cartridge – 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 Pro65 Warning: Cancer and Reproductive Harm
Tap for details → P65Warnings.ca.gov
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Overview
Built for the job.
Our 3M™ urethane seam sealer is a high solids seam sealer ideal for sealing automotive and RV seams and joints. It adheres well to bare metal, primed metal and painted surfaces and if desired can be smoothed to a featheredge and/or brushed. Tack-free and paintable after 30 to 45 min, this urethane formula is…
3M 08367 is a one-component, black paste seam sealer supplied in a 310 mL dual cartridge. It is designed for sealing seams and joints on aluminum, bare metal, and primed surfaces prior to final coating, providing a durable barrier against moisture and corrosion.
The formulation cures at ambient temperature within 24 hours, allowing full handling after the cure period while maintaining flexibility during the initial set. Application temperatures from 25 °F to 180 °F ensure reliable performance in most shop environments. With a VOC content of 9.8 lb/gal, it meets typical regulatory limits for low-emission products.
Due to its classification as an acute toxicity, carcinogen, and skin corrosive material, appropriate personal protective equipment is required: eye protection, chemical-resistant gloves, protective clothing, and a respirator in confined spaces. Ensure adequate ventilation during mixing and application.
Why Pros Choose 3M 1-Component
- High quality, single-component formula adheres well to bare metal, primed metal and painted surfaces
- Moisture curing property provides excellent performance in high heat and humidity environments
- Non-shrinking, non-cracking, low/no odor formula remains flexible and offers superior results to solvent-based sealers
- Paintable after 30 to 45 min
- Thick consistency is able to fill large voids
- Can be smoothed to a featheredge or brushed
- Recommended for use with 3M™ single-component cartridge applicator gun PN08990 or 3M™ professional caulking gun PN08993
How to Use
For adhering floor coverings, bare metal, door hem flanges, door jambs, door skins, exterior seams and joints, fastening headliner and ceiling systems, floor pans, galvanized, general-purpose, interior seams and joints
- Clean the substrate (aluminum, bare metal, or primer) to remove oil, grease, and loose particles; ensure a dry surface.
- Apply the paste at temperatures between 25 °F and 180 °F using a suitable applicator (e.g., spatula or brush). No mixing is required for this 1-component product.
- Spread evenly to achieve full coverage in a single coat; avoid excessive buildup that could affect flash time.
- Allow the seam sealer to cure for 24 hours before handling or applying subsequent layers.
Compatibility
Compatible substrates: Bare Metal.
Compatible paint systems: Urethane, Epoxy, Solvent.
Specifications
| Part No. | 8367 |
|---|---|
| Product Line | MMM |
| MFR Model | 08367 |
| Standard/Approvals | California Pro65 Warning: Cancer and Reproductive Harm |
| Application | For adhering floor coverings, bare metal, door hem flanges, door jambs, door skins, exterior seams and joints, fastening headliner and ceiling systems, floor pans, galvanized, general-purpose, interior seams and joints |
| Manufacturer | 3M Products |
| Alternate Part Number-1 | 60455054621 |
| UPC | 051135083673 |
| Brand | 3M™ |
| Maximum Sale Quantity | 12 |
| Maximum Sale Day | 7 |
| Applicable Materials | Bare Metal, Primed Metal, Painted Surfaces |
| Composition | 15 to 40% Urethane Polymer, 10 to 30% PVC, 10 to 30% Sulfonic Acids, C10-18-Alkane, Ph Esters, 5 to 10% Xylene, 1 to 5% Calcium Oxide, 1 to 5% Ethylbenzene, 0.5 to 1.5% Hydrotreated Light Petroleum Distillates, 0.1 to 1% Carbon Black, 0.1 to 1% P,P'-Methylenebis(Phenyl Isocyanate) |
| Application Time | 10 min |
| Paintable (Y/N) | Yes |
| Specific Gravity | 1.17 |
| Base Type | Urethane |
| Component | 1K |
| Odor/Scent | Solvent |
| Color | Black |
| Container Size (mL) | 310 |
| Flash Point | 92 deg F |
| Container Type | Dual Cartridge |
| Form | Paste |
| Temperature Rating (deg F) | >200 deg C Autoignition, -25 to 180 |
| Type | 1-Component |
| Curing Time | 24 hr |
- VOC
- 9.8 lb/gal
- Application Temperature
- 25-180 °F
- Compatible Substrates
- Aluminum, bare metal, 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 can I apply this seam sealer to?
It is compatible with aluminum, bare metal, and primer-coated surfaces.
How long does the sealant take to cure?
The product reaches full cure in 24 hours under normal conditions.
What personal protective equipment is required when using this product?
Wear eye protection, chemical-resistant gloves, protective clothing, and a respirator suitable for organic vapors.
Within what temperature range can I apply the sealant?
Apply between 25 °F and 180 °F (-4 °C to 82 °C) for optimal performance.
Documents & Safety
DANGER: This seam sealer contains hazardous chemicals that can cause serious health effects including cancer, reproductive harm, eye damage, skin corrosion, and respiratory issues. Required PPE: safety glasses or goggles, chemical-resistant gloves, protective clothing, and respirator. Avoid skin and eye contact, inhalation of vapors, and ingestion. Use only in well-ventilated areas. Can cause aspiration hazard if swallowed. 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 Bare Metal. 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 310 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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