It's my understanding that epoxy can be made with different chemical makeups. It therefore depends on the particular manufacturers epoxy as to whether or not acetone is compatible. Acetone can be used with some epoxies as a thinner, but not with others. Acetone is not always pure. Sometimes it is recycled and contains impurities. Some epoxy manufacturers recommend against using acetone because of it's health hazards and possible impurities. To get the specifics on the epoxy you are using it is best to contact the manufacturer, they can be a major source of technical info on the subject.