Question: Have there been any new adhesives for consumer or handyman use recently?

Answer: It is fair to say that there have been no major new chemistries over the past few years, although many adhesives have been reformulated to make them “greener” or to use more sustainable ingredients.

However, innovative marketing has given us a couple of very interesting and useful products. Although I cannot mention trade names in this column, two types of single-component adhesives that cure by interaction with atmospheric moisture have found commercial success. The first of these is a moisture-cured polyurethane that cures rather slowly but provides very good performance, particularly on substrates such as wood. This technology has been around since the 1970s. However, it was not marketed well until recently because of the adhesive manufacturers’ obsession with selling products that cured “instantly,” such as the superglue type of cyanoacrylates.

A second successful product, being marketed by a European company, is a moisture-cured silicone adhesive. The novel feature of this product is that it resembles a silicone bathtub caulk in its chemistry, but has been thickened into a putty consistency. This allows it to be molded by hand and used to bond, fill, and repair many household items. The actual adhesive strength is not particularly high in comparison to other consumer adhesives, but the cured product’s extreme flexibility makes many successful repairs possible. Cured silicones have interesting properties such as outstanding performance at both low and high temperatures. The product is packaged in moisture-impermeable packets, and can be compared with the well-known hand-moldable epoxy putty sticks, which will give much higher bond strengths but not the same sort of flexibility or extreme temperature performance.