3M Fast ‘n Firm Seam Sealer – 08505

Seal exterior seams and joints with the quick setting 3M Fast ‘n Firm Seam Sealer. This sealer shows good adhesive tendencies to clean primed or painted metal and is available in a 1/10 gallon cartridge.

The seam sealer is a quick drying formula that allows you to paint over it within minutes of application. This low-cost product works well on your budget and helps you perform automobile repair jobs with ease. An advantage of this efficient seam sealer is that it does not shrink, thus averting the need for spending time, money and effort on rework. Store it at room temperature and use it in a suitably ventilated area. An unopened container of this product has a shelf life of 12 months.

What are the automobile applications of this seam sealer?

It helps accomplish several external or non-passenger compartment sealing applications. We recommend that you do not use this sealer in interior passenger compartment or trunk compartment applications.

How to use the 3M Fast ‘n Firm Seam Sealer

• Use it over paint or primer when you want to apply it to metal, since direct application on bare metal may not protect against corrosion.
• Clean and dry surface with an efficient adhesive cleaner. Wait for the primer to completely cure before you use an adhesive cleaner.
• Cut nozzle tip so that you get 1/4″ diameter bead. Remove seal at the base of the tube.
• Place the tube inside a calking gun and engage ratcheting mechanism.
• Apply bead width as desired and tool to get the desired appearance if you find necessary. After the sealing is complete, unfasten ratchet to stop the flow.
• Wait for the sealer to dry before you apply paint on it. Thicker beads take a longer time to cure.

Key Features of the 3M Fast ‘n Firm Seam Sealer

• Offers exceptional sealing exterior joints
• Adheres to clean metal, primed metal and paint surfaces
• Skins over effortlessly
• Can be painted within half an hour
• Less chance of problems associated with shrinkage
• Exhibits good sanding and tooling properties
• Accrues money savings since there is less chance of rework

Technical Specifications

• Color: Tan/Beige
• Hardness (Shore A): 50
• Adhesion to Primed Steel: Excellent
• Skin over time: 5-10 minutes
• Paintable: 30 minutes
• Pack Size: 1/10th gallon
• Sandable: Somewhat, not recommended

NOTE: Do not seal interior automotive seams in passenger compartment or trunk (use 4135 – 3m Ultrapro autobody sealant – 08300, for those areas)

WARNING: This product contains a chemical known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to