I use the plastic green pyramids for parts right off the CNC machine, and it definitely takes out all the machining marks in maybe 2 hours. I am using a Burr King 200SX (I think that's the model, it's 200-something or other).
I didn't have any luck with the walnut shells for polishing, then I realized - duh - I was running them bare, without any polishing compound. At Eastec, a Burr-King rep told me I obviously need to use a polishing compound in the walnut shells.
Question... I have seen companies that sell treated walnut shells, and they are VERY expensive. Can I just add my own polish to the walnut shells? I was thinking if I could find some powdered aluminum compound, I could just add an appropriate amount to the walnut shells and that would do the trick. Anyone know where I can get it? Or could I just use off-the-shelf aluminum polishing compound (which is usually a paste or liquid, not a dry powder)??
I also have to say I didn't notice a ton of difference running the green pyramids wet vs. dry. I got some sort of soap liquid that you're supposed to mix with water. It maybe makes the finish from the green pyramids a little better, but it's not night and day.
I did notice that if I take a part, run it in the pyramids for a couple hours, I can take it right to the buffing wheel and get a mirror finish with the jewelers rouge and a flannel wheel, so the green pyramids are definitely putting on a great pre-polish finish. I just need to get the right compound for the final polishing.
In my case, the parts will get anodized or chrome plated afterwards, so the better finish I can put on them first, the better they come out with less manual labor later.  |