- Working With Moldin' Oldies Parts
While quite strong, these polyurethane castings are just a bit "softer" than standard polystyrene plastic parts. If sanding is necessary, they sand beautifully. They should be finished with enamel-based primers and paints. (Experience has found out that lacquers don't work as well and should probably be avoided.) Due to the possibility of a thin film of mold release, these parts should be washed with soap and water to remove this film, which may interfere otherwise with the bonding of paint. These parts are also resistant to solvents, so typical plastic cement or plastic welder will not work on them, as those types of glues are meant for polystyrene and not polyurethane plastics. Epoxy is ideal for bonding these parts. Use sandpaper to slightly rough up any surface to which you want epoxy to adhere to to give the surface a little “tooth” on which the epoxy can “bite”. CA glues (like our Bob Smith Products) also work well as adhesives on these parts.