Plastic Resin Glue is also known as urea formaldehyde glue. Some brands come in a dry powder form to which you add water. Others involve a liquid resin and you add a (supplied) powdered catalizer to it in particular proportions. Some products, such as Unibond 800, have three differently colored catalizers to help you disguise the glue line in light, medium or dark-toned woods.

Plastic Resin Glue dries to a glass-hard consistancy in about eight to ten hours, depending on the ambient temperature. The hotter the weather, generally speaking, the faster they cure. And unlike PVA-based yellow and white glues, which cure to a softer, more pliable consistancey when dry, plastic resin glue isn't susceptible to cold creep as a result of how it dries. This makes plastic resin glues an excellent choice for bentwood laminations and veneering.

One of the biggest benefits to using plastic resin glues are the long (30+ minute) open times. But one of the biggest downsides is that if the ambient temperature OR the temperature of the wood is below about 55° the glues won't cure. If the temperature is low then the technique for use is to tent the piece with a packing blanket and bring in either a ceramic space heater or an electric blanket.

Resorcinol, DAP's Weldwood, Unibond 800 and Urac 185 seem to be the most popular brand names. Each has performance benefits that make them the glue of choice in particular applications.

Gorilla Glue is NOT a plastic resin glue. It's a polyurethane glue and does not match the working properties, open time or adhesive benefits that come with plastic resin glues.

A word of caution about urea formaldehyde glues centers around that word 'formaldehyde'. Mixing this glue generally requires the user to wear a NIOSH - approved dust mask to keep the dry powder from being inhaled. Formaldehyde will do the lungs no favors. However, once the powder is completely mixed (either into the companion resin or into water, as is the case of Dap's Weldwood) then the mask can come off.

Finally, plastic resin glues may fail in exterior applications if they're subject to direct exposure to wind, rain and sun. Look to Smith's Tropical Hardwood Epoxy for superior results in this application.