Polytetrafluoroethylene (PTFE) is a high-performance plastic used in a variety of industries, particularly for its heat and chemical resistance and “non-stick” properties. However, PTFE has a low surface energy that does not allow adhesives to wet its surface and subsequently bond.

We are using epoxy adhesives to bond steel substrates that are exposed periodically to both 150˚C and as low as 0˚C. Our problem is in maintaining adhesion to the two steel surfaces at such divergent temperatures because of the response of materials to thermal conditions when going through heating and cooling cycles. Do you have any suggestions?

Called thermoset polyesters, these materials are glass fiber-reinforced unsaturated polyesters. They are also often referred to as “sheet molding compounds” (SMCs), “fiber-reinforced plastics” (FRPs), or simply “fiberglass.”

Question: My colleague and I are working on a unique challenge of trying to find a solution for manufacturing urethane-based adhesives that are quite sensitive to moisture exposure.

You can obviously package your moisture-sensitive sealant in glass or metal cans or tubes, which will totally prevent moisture ingress. Aluminum tubes are widely used for this type of product, as long as you have good crimps.

I have worked with companies that manufacture superglue and polyurethane glue, both of which are single-component, no-mix adhesives. Superglue, which is the common term for cyanoacrylate adhesive, has been around for about 60 years. In contrast, the polyurethanes are about 20 years old in the retail market and somewhat older in professional woodworking. I admit to using both types of adhesive regularly.

I realize that the meter/mix equipment can be a major inconvenience. Adhesives come in two forms, namely two component or one component. Two-component adhesives are mainly epoxies, reactive acrylics, or polyurethanes.

You have a wide range of structural adhesive possibilities here. Normally, you require an adhesive that has been toughened with a rubber for this. Very rigid, quite brittle adhesives have been successful, however.

Numerous technologies and patents cover debondable structural adhesives. For your small parts, however, I can suggest a few simple alternatives.

Adhesives have become prevalent in solar applications to replace mechanical fasteners and welding.