With building resin, since they are normally cast in mass quantities, casters use mold release to help keep the molds in good conditions. The mold release will keep paint and other things from sticking to the surface of the kits, so prior to painting, it is imperative to use a degrease agent to clean the resin parts, otherwise the paint and primer will not stick. I usually finish the initial sanding and cleanup work before soaking the parts. I use an industrial strength cleaner called purple power cleaner; but other degreasing agents such as oven cleaner, simple green, formula 409, etc. Below is a picture of the resin parts soaking in the purple cleaner. One of the parts has putty applied and sanded, the cleaner will not hurt the cured epoxy putty.
The parts are soaked for at least 24 hours to ensure that the mold release agent has been completely dissolved off the parts. Following the soak, I clean the parts using an ultrasonic cleaner. Without this cleaner, I would normally take an old toothbrush, dish soap in warm water, and scrub the parts to ensure that all the small detail areas have been cleaned properly. Now with the ultrasonic cleaner, this process is simplified and the scrubbing session cleans the parts much better and more efficiently. The cleaning solution for the ultrasonic cleaner is water with a couple of drops of white vinegar. Other products such as dish soap, industrial cleaner can be used as well.
After running the cleaner, just take the parts out and dry them on some paper towels. Once dried, the parts are ready for priming.
The following is a video showing the use of the ultrasonic cleaner in use to scrub my resin pieces. The ultrasonic cleaner is a great tool that I also use to clean my airbrushes.
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