Our current sealant recommendation for all vintage trailer restoration is Tremco's U1600.  It is Tremco's replacement for the legendary TremPro 635 that we've sold for years and is recently discontinued in favor of this formulation.

U1600 is an improvement in durability and performance while offering the same usability as the well-regarded TermPro 635. If you liked the old TremPro 635, you'll love U1600. 

NOTE: Packaging on U1600 is evolving.  It is currently packaged under the name TremGlaze but will soon be changing to another name.  The formula remains the same.

Tremco was founded in 1928 and they have been the leading producer of premium polyurethane-based sealants for decades. They have one of the largest R&D departments in the sealant and weatherproofing industry and vintage trailer restorers use Tremco products more than any other.

Vintage Trailer Supply has been offering their polyurethane sealants for as long as we've been in business (25+ years!) and we work directly with Tremco to follow the latest formulas and recommendations.

In technical terms, U1600 is a high performance, low-modulus (highly elastic) polyurethane hybrid sealant. It is applied with a standard caulking gun. It moisture cures, meaning it pulls humidity from the air to chemically cure.

It offers these benefits:

• Extreme Resilience: It is durable, extremely UV stable, and weather-resistant.
• Excellent Movement: flexible/elastic sealant with ± 35% movement capability ideal for thermal expansion and contraction, and body panel flex.
• Skins over in 30 to 90 minutes (at 75 °F & 50% RH), giving you time to work.
• Tack free in 3 to 4 hours (at 75 °F & 50% RH)
• Aggressive Adhesion: Sticks to a variety of substrates including aluminum, fiberglass, glass, vinyl and wood. 
• Quick and Easy Application: Apply with conventional hand caulking and air gunning equipment
• Paintable: Allow it to cure first.

Surface must be clean and dry before application.

Apply the smallest bead you can, understanding that you will be tooling the bead into the seam after application. For a cleaner finish, mask the sides of the seam with tape prior to filling. Dry tooling is always preferred (a wooden stick or your finger covered with a glove), although xylene can be used in limited amounts to slick the spatula if needed.

Don't forget to order inexpensive disposable syringes for easier caulking! 

Click here to see a PDF version of the Tremco U1600 Technical Data Sheet

*a note about temperatures.... At 75 Degrees F and 50% relative humidity, cures to a depth of 3/32" in one day. For every 10 Degrees F colder, add one day. Practically, it isn't a good idea to apply it when temperatures are below 40 Degrees F. Please read the Product Data Sheet above for additional information about application conditions.