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)

Steve,

Thanks for the info on polishing the ZF case. I actually just want the flat matte look that I saw on a transaxle while I was in Montana the other day.

The guy said that he had his case Glass Bead Blasted. It was very smooth but did not look polished. I found this old post from 2007 with a picture of a glass beaded case (the pic is about halfway down).
2007 Post of Glass Beaded Case

Here is my problem – When I glass bead the aluminum it has the clean matte finish but if you look close it still has some waves and very minor indents in the metal. From a distance it looks pretty good, but up close it looks only half finished.

I would bet that it is just the way the metal came out of mold when the case was cast. I was wondering if in order to get a totally flat surface, without the minor waves or indents, if I should sand it, use a heavier blasting media, or use something I have never heard of, etc.

I have no desire to polish it myself. As I get older, and hopefully wiser, I have learned that often times it is better to pay someone else to do the grunt work while I do something I really enjoy. Thanks again for all the help.

The ZF in the picture looks great. It probably took most of the sanding steps for polishing to get it to look that way. Good luck with this.

Thanks again Steve. That's what I was afraid of. I'll let post my progress if I decide to continue with this project.

May just send it off and let someone else use their elbow grease.

FWIW, I was in Steve Wilkinsons shop last year and he had a beautifully finished ZF that looked just like the one in that other thread Garvino posted. Anyway, Steve told me he glass beads the cases, then sprays with a satin clear to fill all the pits and voids so they don't get filthy so easily.

Garth66,

That’s interesting. Do you have any more information on the satin clear?

For instance, do you know if it is an automotive clear that has to be mixed and sprayed with a gun or just some "off the shelf" product that comes in a spray can?

Thanks for the information. I may now end up doing this myself again.

http://www.eastwood.com/paints/clear-coats.html

As always, the desired look is a matter taste and needs to compliment the rest you have going on. Other than the remarks I made in the previous thread you referenced, IMO polished cases are the easiest to clean and maintain in the long run. They wipe down easily. Some of the painted or powder coated cases do as well but they inevitably age, discolor, flake etc, and then you have a bigger job to strip it before you get back to the point you're at now.

If you are going to bead blast your ZF while it is completely assembled, of course plug the vent tube, but also take care when you blast around the drive yokes. The seals are designed to keep oil in but not necessarily high velocity sand out.

It's been years now but I blasted my zf while I had the engine out and was doing some general freshening. I packed a piece of clear plastic tube in front of the seal before I blasted. If you have already blasted it I'd recommend you take a close look and dig out any sand that may have collected between/around the seal and drive yoke shaft so it doesn't abraid the surface. I also replaced some hardware, masked off the side plates and end cap and gave them the rattle can treatment which has held up amazingly well.

Take care,
Kelly