Fiberglass box pads are widely used products that many utility companies mistakenly regard as generic. Because price-driven markets force many manufacturers to reduce costs wherever possible, it is common for some to produce only marginally acceptable box pads, resulting in costly “forced” replacement of these inferior products after only a few years of service.

These manufacturers cut costs by using male molds, low quality fillers and simplistic mold designs. Gel coats are eliminated, or the cheapest ingredients are used. Gel-coated products have 10 times the abrasion resistance of non-gel-coated parts. Some companies use straight resin with UV inhibitors to cut costs, but these are much less abrasion-resistant to garden tools, etc. Highly filled resin and low glass reinforcement are the industry norm.

Certain fillers can dramatically affect the life of fiberglass products. Merchandise produced using so-called “chopper-guns” are highly susceptible to inconsistent laminate thickness, due to operator error. More expensive woven “roving fabric” is seldom used by many companies, resulting in poor glass reinforcement. Similarly, encapsulated wood used for support by some box manufacturers often hastens degradation of the vault and resultant failure.

ProGlass products, by contrast, are made with High Quality materials and are the most durable boxes available in the industry. Our boxes are built using highly sophisticated mold designs with built-in intricate ribbing that extends into a wide supporting flange. We begin with an ISO-NPG gel coat formulated with UV additives in Munsel Green. An isothalic DCPD resin, filled with 43% ratio of calcium sulfate flame retardant filler that  has successfully passed the UL E-84 and UL E-162 flame and smoke tests.

Calcium carbonate often is used as filler by low-end manufacturers, which is nothing more than fine sand. This filler adds nothing to the flame retarding ability of the resin and results in faster degradation of the composite. All “budget” fillers reduce the design life of fiberglass because of their increased water absorption. This creates a gradual softening and loss of hardness, again resulting in premature structural decomposition and vulnerability.