OK, not really metal-related, but I need to machine some acrylic stock and was wondering what a good coolant or lubricant would be? I've read that 30% liquid Ivory soap-70% water works, but are there any others to consider?
Thanks, Dave
Dave Standard coolants work well, maybe a little weaker than usual (1-3%) or a Cold air gun. The important thing is to keep the heat out of the workpiece. Use very sharp tools. If using carbide inserts, high positive ground and polished edges are best.
Blown air or even cooled air. There are companies that make liquid-free coolant systems that work witha simple compressor. They take compressed air and blow air at 0 or colder I think... But you may have to experiment as it may cause the acrylic to become brittle.
Avoid solvents--which often create crazing of the surface.
Harold
Water works well. I dpn't know about the liquid soap. Cold air also works well. Sharp tools for turning or milling. For drilling stone the drill edges a bit to prevent grabbing. Most important: DO NOT USE ANY OIL. NOT EVEN SOLUBLE OIL IN WATER. If oil is used, especially when drilling holes, the acrylic will crack. It probably won't crack right away. Sometimes overnight it will. Lots of times it takes a couple weeks. Sometimes it may even take a couple months. But it will for sure crack. An example of this is an acrylig pepper mill. All molded without any drilling usually. But eventually the oil in the pepper will make it crack. The cracks will usually start where the steel grinder parts are pinned or screwed to the acrylic. Eric R Snow, E T Precision Machine
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