Weldbond is a polyvinyl acetate (PVA) adhesive, and there are other brands of PVAs on the market.
Why is Weldbond preferred by many mosaic artists, and why does Mosaic Art Supply’s online information refer to Weldbond as “the best” mosaic adhesive?
Weldbond is thick, and the extra viscosity can be invaluable for taking the frustration out of doing detailed mosaic work. It’s nearly impossible to avoid bumping tiles as you work, and the thicker the glue, the less they move.
Strength and Durability
Like most any water-based adhesive, Weldbond ruins if it freezes before use, but the following explains why we recommend Weldbond based on its strength in cold weather.
Artist Joe Moorman decided to carry Weldbond when he started Mosaic Art Supply in 2002. It was the thickest, strongest PVA adhesive he had ever used, and he had learned from other artists that Weldbond had been certified for use in space by NASA, where adhesives need to withstand cold temperatures.
Joe paid for his engineering degree by working a sequence of internships for a major aerospace company. One of the internships was in materials testing lab, where Joe observed how effective cold temperatures were for destroying things, including sophisticated high-performance aerospace adhesives.
Joe figured that since Weldbond was made in Canada, the people making and testing it probably had more first-hand experience with glues becoming brittle and cracking in low temperatures. Also, the certification by NASA for use in space had to mean that Weldbond had been well tested by a third party, possibly several parties.
Joe recommends Weldbond now more than ever because he has been able to see how well his own mosaics have lasted, even the unfinished and abandoned pieces that have been stored in outside garages for years.
In early 2011, Joe attempted to recycle an unfinished, ungrouted mosaic made on a 2 ft x 4 ft plywood panel back in 2005. The mosaic was soaked in water and detergent for a month or two, but most of the materials (glass, ceramic and stone) had to be pryed of with a screwdriver, and even the small pieces usually broke instead of coming free from the Weldbond.
Weldbond securely bonds to wood, glass, fabric, linoleum, styrofoam, concrete and other art materials. It is water-based, non-toxic, dries clear and is very water-resistant when fully cured.