17prospective buyer

So, i always blast outside generally, on a large tarp, with two saw horses to support large pieces, or for small items like hardware (bolts, small brackets etc) i place a large sheet of thick glass on top of the saw horses as eye protection, and then blast the pieces in a plastic container with wire mesh in it to prevent the hardware from moving around too much. I would usually blast in 2 stages with different medias, first is angular media to strip all corossion and paint, so sand or coal slag. Then the second stage would be with a spherical media, glass beads, which lightly polishes parts giving them a satin sheen rather than the matte, very porous finish from angular media.

I just got a blasting cabinet however, so i can get very high recovery rates for media, this also makes contamination a non issue. This will be just for my finishing stage, i will only use spherical polishing media in it. Wondering if i should use steel shot or glass bead. Steel shot is much more durable obviously, there's almost no dust in shot, and since it doesn't fracture, there wouldn't really be any dust in the cabinet. Would it be suitable for aluminum as well though? I brought this up because i have pressed the outer races out of my front wheel hubs so they are ready to blast.

dr bob

Before you blast the hubs with anything, mask or plug the bearing bores so you don't revove any metal at all. The parts are aluminum so they don't rust. A pass with a brass or soft steel brush, a hand brush not power, is usually all that's needed to remove stuff that's landed on the aluminum. A bath in parts dip does a good job, or a soak in a slight higher pH detergent bath will finish the degreasing process. Leave them in too long and you get a gray hydroxide layer. Brush again. The natural oxide layer will return shortly anyway.

The original as-forged finish on the hub is satin. Any hard blast will damage that beyond any restoration options. The studs are steel and can rust. Perhaps after the aluminum is cleaned and prepped, you could mask all but the studs (think plastic shield with five holes in it for the studs...) and lightly blast it just to get any rust off. Anything more starts to erode the threads. Since this is steel, you can more easily use a small rotary steel brush at low speed to clean the crud out of the threads without stripping any metal. Use a little spray instant cold galvanizing on them and they will be fine for a long time.


I know you have a new toy to play with. It is handy for lots of things, but restoration of a forged and machined part should be done with maybe fine walnut hulls or glass beads as recommended below, else by hand with chemicals and a few brushes.

polecat702

I only use glass bead for aluminum. My Harley engine pieces ( heads & cases) always look new years after they were glass beaded. For most metal pieces, I've switched over to soda blasting. Soda dissolves when the parts are washed.

17prospective buyer

Removed all the studs and glass beaded them, then cleaned out all the threads of all the built up gunk and antiseize till the lugs spun on with no resistance. Had them plated with yellow zinc, good for corrosion resistance and it looks better than OEM.

Will mask the outer race seats, was going to do this anyways. However i have to disagree that blasting with a spherical media will "damage" the finish. Mine have a good coating of white corrosion on them, spherical media doesn't remove any solid material anyways, just peens the surface, creating a semi reflective finish. You should see how my water bridge came out with glass beads... better than new and creates a surface finish that is smooth enough that gasket surfaces can be blasted too.

dr bob

A lot of those parts look pretty now, but are a) no longer the original finish, for those of use who cherish such things, and b) missing the original plating or oxide coatings that protected the parts from further oxidation. Al bits will turn dull gray again, fe bits will rust.

Good luck with your quest!

17prospective buyer

I had all of the shown parts except the aluminum ones yellow zinc plated. Thanks anyways though.

depami

Pics or it never happened...!......!

17prospective buyer

Ok... they came out great.

17prospective buyer

One more thing to add, with the sheer quantity of parts i have removed during this project, and the duration of time i'm away from the car, i can't remember where alot of stuff came from. Thinking of setting up a wrenching party to put stuff back together, combining experienced 928 owners together is pretty powerful, i bet we could get alot done in just a weekend provided i have parts ready to be installed.

Rob Edwards

Take sets of pictures of 10 items lined up, left to right, and folks can make lists of what each piece is. Label each picture A,B,C, etc.

Livio928

Where did you send you pieces to be zinc plated?

17prospective buyer

Precision Plating here in London, great guys. Will do any batch of parts i bring in, no job too small. No minimum charge, they just size up how much it will cost based on part type and quantity right there at the counter. Always had great results from them, i've done 3 or 4 batches there with yellow zinc and all perfect results.

http://www.precisionplating.com/