3M
3M 8368 White 1‑Component Seam Sealer 310 mL Cartridge – 24 hr Cure, Paintable After 30 min
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Hazardous material · Paste
This hazardous material ships ground-only. A handling surcharge may be added at checkout.
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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 08368 is a one-component, white paste seam sealer supplied in a 310 mL cartridge. It is designed for sealing seams and joints on aluminum panels, bare metal surfaces, and primed substrates prior to filler or paint application.
The formulation cures at ambient temperatures from 25 °F to 180 °F with a full cure achieved within 24 hours, providing reliable adhesion and flexibility under varying shop conditions. With a VOC content of 9.8 lb/gal, the sealer meets typical environmental regulations while delivering consistent coverage for seam repair work.
Handling requires standard protective equipment: eye protection, chemical-resistant gloves, protective clothing, and a respirator in well-ventilated areas due to acute toxicity, aspiration hazard, and classification as a carcinogen and skin corrosive. Follow the SDS first-aid guidelines for inhalation, skin contact, eye exposure, and ingestion.
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 sealing of seams to prevent intrusion of water, dust, air, fumes, may be used for interior or exterior seams of primer coated substrates
- Clean the substrate (aluminum, bare metal, or primed surface) to remove oil, grease, and loose particles; ensure it is dry.
- Apply the 1-component seam sealer with a suitable trowel or spatula at the recommended application temperature of 25 °F-180 °F.
- Allow the sealant to cure for 24 hours before handling or applying additional coats if required.
Compatibility
Compatible substrates: Bare Metal.
Compatible paint systems: Urethane, Epoxy, Solvent.
Specifications
| Part No. | 8368 |
|---|---|
| Product Line | MMM |
| MFR Model | 08368 |
| Standard/Approvals | California Pro65 Warning: Cancer and Reproductive Harm |
| Application | For sealing of seams to prevent intrusion of water, dust, air, fumes, may be used for interior or exterior seams of primer coated substrates |
| Manufacturer | 3M Products |
| Alternate Part Number-1 | 60455054639 |
| UPC | 051135083680 |
| Brand | 3M™ |
| Applicable Materials | Bare Metal, Painted Surfaces, Primed Metal |
| Composition | 20 to 40% Urethane Polymer, 10 to 30% PVC Polymer, 10 to 30% Sulfonic Acids, C10-18-Alkane, pH Esters, 4 to 10% Xylene, 1 to 5% Calcium Oxide, 1 to 5% Titanium Dioxide, 0.5 to 2% Ethylbenzene, 0.5 to 1.5 Hydrotreated Light Petroleum Distillates, <0.2 P,P'-Methylenebis(Phenyl Isocyanate) |
| Application Time | 10 to 20 min |
| Paintable (Y/N) | Yes |
| Specific Gravity | 1.17 |
| Sprayable (Y/N) | Yes |
| Base Type | Moisture-Curing Urethane |
| Component | 1K |
| Color | White |
| Container Size (mL) | 310 |
| Flash Point | 92 deg F |
| Container Type | Cartridge |
| Form | Paste |
| Temperature Rating (deg F) | -25 to 180 |
| Type | 1-Component |
| Curing Time | 24 hr |
- VOC
- 9.8 lb/gal
- Application Temp.
- 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 it take for the seam sealer to cure?
The product cures in approximately 24 hours at temperatures between 25 °F and 180 °F.
What personal protective equipment is required when using this product?
Wear eye protection, chemical-resistant gloves, protective clothing, and a respirator approved for organic vapors.
Documents & Safety
DANGER: This seam sealer contains hazardous chemicals that can cause serious health effects including eye damage, skin irritation, respiratory problems, and potential cancer risk. Required PPE includes safety glasses, chemical-resistant gloves, protective clothing, and respirator. Avoid skin and eye contact, inhalation of vapors, and ingestion. Use only in well-ventilated areas. If exposed, flush eyes with water for 15 minutes, wash skin thoroughly with soap and water. 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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