Welcome to LMTmag.com, the social and information hub of the dental lab industry. Connect with industry peers and vendors, ask questions, sign up for events, review products, read LMT articles and industry news and more!
I agree with Jeff. It's likely contamination of the metal from finishing stones. We had problems when a stone used for removing oxides from implant cases before polishing was then mistakenly used to finish copings. If any of the metal from the machined gold interface gets into the stone, it can no longer be used for finishing.