Oil in cadmium plating bath

A. I remember the old days when platers would routinely spread newsprint over the surface of their cadmium and zinc plating baths to sop up the oil daily. Fortunately, I think those days are gone. But oil can come from many sources: drips from an overhead hoist or crane; from your air compressor if you are using it for agitation in lieu of a regenerative blower; the bearings on plating barrels, etc. But I'd bet on the parts regardless of what the lab says :-)

A. I would agree with Ted. The cadmium plating bath is a very good cleaning solution due to the cyanide and sodium hydroxide it contains. It is quite possible you are removing oil which has passed through your cleaning step. Recheck to be sure your cleaners are up to strength, do not have floating oil, etc. Also, once you remove the oil from the plating tank it is necessary to clean the tank around the solution line since this is where oil accumulates and will redissolve.