Valiant sailboats and Uniflite powerboats were built, for a time in the late 1970s, with a polyester resin that had a fire retardant additive. The additive caused the boats to blister badly.
Uniflite dropped the fire retardant additive in the early 80s, and due, in part at least, to the blistering problems, Uniflite was sold
. The new owner was not interested in sailboats and sold
the Valiant name, molds inventory, and so on to Rich Worstell, who moved
the manufacturing operation to Texas
in the mid-1980s.
According to: https://uniflite.com/history/
The issue regarding the fire-retardant resins causing blisters
in later years (1975+) was a result of a change in suppliers of the fire retardant resin (Hetron). Earlier models (prior to 1975) contained a fire retardant called “Hetron” manufactured by Dupont Chemical and these boats did not have any blistering problems. When Dupont ceased production of Hetron 1975, a different fire retardant was used from a different manufacturer. Unfortunately, the new fire retardant contained a solid form of the chemical bromine which, unfortunately, evolved into a gas when the fiberglass
was warmed sufficiently. This happened to Uniflites in warmer climates like Florida
more then it did in the Pacific Northwest
. This bromine gas created an acid that ate its way out of the gel coat. For this reason, if you were to grind out a deep blister you would notice a “gooey” material. The only way to remove a blister properly is to grind it out, let it dry, then fill the hole with a vinylester resin ($$). It doesn’t solve the problem entirely but should provide a strong barrier (plug) to prevent the blister from reaching the surface again. In reality, the blisters
will likely return.