The beads I am using do not have a rating on them. The packaging lists the ingredients as "glass oxide." I obtained the blast media from a friend who has a radiator shop, they use the beads to clean aluminum radiators without scarring them. If I were to compare the beads to anything size wise, it would probably be the media in a small hour glass found in board games(not a very scientific comparison.) The grains would probably be, say 20% the size of granulated sugar. I have a moisture/oil trap on my airline at my compressor. The blasted surface just seems to have a grayish appearaance to it and just doesn't seem to take dye at all, or very little at best. I thought blasted finishes were supposed to be easier. The possible oil problem should be resolved by the simple green degreaser I am using not to mention the alkaline cleaner I use as my final cleaner shouldn't it? The pieces I was running the tests on were .25x 1.5 x 6" long. The aluminum is just ordinary bar stock. I was running twelve of them at a time with two racks zip tied together and the parts kicked out to each side at about a 30* angle to each other. I ran the parts at about 10.5 amps. My aluminum cathode area is about 144sq" running down each long dimention of my tank with .75" solid copper bus bars.The tank is holding about twenty gallons of sulceric @5% with wetting agents and mist suppressents and running at 70*. As mentioned, I am having great results with the polished finishes, it is just the bead blasted side of the test pieces that are giving me problems. I have ran considerably larger runs in the past with flawless results. Thanks,
EasTTex
|