Thermofused melamine, a composite wood panel with resin saturated thermally set paper overlays, is a standard in the reptile caging industry. Heat retentive and easy to clean, many herp lovers prefer the material over glass aquariums or PVC. Over the last decade, concerns have been raised about the formaldehyde-based glues used to press sawdust and other wood chips into a uniform, coherent sheet. Its the particleboard substrate, not the melamine-impregnated overlays, that posses the alleged risk.
Despite the recent media fervor, particleboard is actually becoming safer as the California Air Resource Board as passed a series of laws drastically reducing the amount of free-formaldehyde molecules allowed. Even imported products must meet this stringent standard imposing a ceiling of.18 parts per million on all products intended for home consumption. Prior to the CARB standards being implemented, particleboard was relatively stable once laminated.
Most of the off-gassing occurs during the cutting and fabrication process when the wood fibers are being disturbed. However, the problem of sagging over an elongated span remains as mills convert their glue lines to more environmentally friendly (weaker) resins, the internal bond strength erodes causing the modulas of elasticity to fall (e.g. less horizontal stiffness) Because of this problem we add interior trusses to our larger cages to reinforce the roof. Actually, we’ve begun moving away from particleboard altogether in favor of a plywood core panel with melamine overlays. This way you still get the clean look of melamine overlays with the strength and lighter weight of plywood.