Reply to "Glass Bead Blasting ZF Case"

You may want to polish a piece of aluminum plate and then bead blast to see if that is what you want. In any case, here are the steps for polishing aluminum. This applies to the ZF case as well.

Start with a coarse grit sand paper (60 to 100). Use this to make the surfaces flat. This takes a long time. Harbor Freight sells sanding sponges in coarse, medium, and fine grit. The coarse grit is good for this step. My latest technique is to use motor oil on the sponge to help the process along. It’s messy but the sponges last longer.

For the intricate areas you will need a die grinder and sanding cones. The cones are rolled up sand paper. Harbor Freight sells these in a kit. Buy the large kit because you will need it. This step also takes a long time. Start with the coarse grit cones.

Once the surface is flattened you gradually go to finer grit sandpaper, stepping down 100 grit at a time. The progression might be 60, 100, 200, 300, 400, 500 and then 600. The idea is to gradually reduce the scratches from previous coarser grit.

Switch to wet sanding at about 400 or 500. Final sanding can be done with 1000 or 1500.

The last step is to buff the sanded surface with red rouge. For the ZF this means various buffing wheels in a die grinder.

Just about anyone that has done this will tell you it is a lot work and probably worth paying a metal polishing shop to do it. (I guess I never got that memo)