I have a Thumblers Tumbler Model B I have had and used for about 40 years. About 6 years ago I started using the wet process with stainless pins for polishing my brass. Using 5 lbs of pins and a pinch of lemi-shine along with a tad of Dawn dish washing liquid tumbling for about 2 hours depending on how dirty the brass was, has really worked well until now. I have been on a massive, in my opinion brass cleaning project. I started getting brass not as clean as I thought it should be and the water being poured off was really black. I was changing the water a couple of times during the tumbling process to get the desired results. Now it does not work at all. The water comes out jet black and the brass is worse than when I started. If you run your hands through the pins it puts a really black residue on your hands which is also hard to get off. My thoughts are the rubber is deteriorating similar to when your windshield wipers start going bad and you take a paper towel and wipe the rubber it comes off really black. I have soaked the pins in dawn and water and rinsed a half dozen times so far trying to get the pins clean but still have a way to go. I have ordered a new rubber barrel hoping this takes care of the problem. Have any of you had this type of reaction before?
Thanks for your thoughts,
gmsharps