We always talk about Vulkem sealant on the show. TremPro 635 Polyurethane has replaced Vulkem, which has been getting hard to find. Don’t use silicone on your aluminum trailer! You need this stuff. An ounce of prevention….
TremPro 635 is the modern version of the legendary Vulkem polyurethane sealant. It is a technologically advanced no-VOC silylated polyurethane. Silylated Polyurethanes are known as SPURs and meet or surpass the performance of the old polyurethanes like Vulkem and Sikaflex 221 in transportation applications in every meaningful way.Here are excerpts from Tremco’s descriptions of 635: “TremPro 635 is a high performance, low-to-medium modulus, one-component, gun grade polyurethane sealant. It utilizes a solvent-free technology, which represents technical advances over existing polyurethane systems. . .TremPro 635 is specially designed for use as a topical sealant in the fabrication of trailers, trucks, campers, buses, trains and specialty vehicles. . .TremPro 635 demonstrates excellent physical properties regarding adhesion, vibration, movement, shear strength and weather-ability.”Silylated polyurethanes have been successfully formulated to offer a good balance of mechanical properties together with application benefits such as immediate paint-ability, improved UV stability/weather-ability and superior adhesion performance. The excellent adhesion of these sealants to conventional construction substrates such as glass and metal has recently been shown to extend to a variety of plastics like PVC, ABS and polystyrene. This wide range of performance makes sealants based on this technology ideally suited for numerous industrial, transportation or automotive fabrication applications.