Letter 18352

Buffing & polishing rims

++

I would like some advice on buffing out my grey factory auto rims. I would like to do this myself and need to know what materials I need and what steps I should take.

Melissa Kay Soles
- Whiteville, North Carolina

The "grey" wheels you're in reference are silver color powdercoated, which you have to remove if your want to polish and buff the bare aluminum to a mirror luster. Regardless of what you hear, the toughest, baddest, meanest strippers out there have a tough time removing powder coat.

You didn't mention the spoke configuration, but I recommend you remove only the coating from the outermost surfaces for polishing and buffing to a mirror, chrome-like luster. Surfaces other than the outermost surfaces, such as the sides of spokes, etc., are "shadowed" anyway, and it would be much better to retain the original factory finish in these less visible areas for corrosion protection.

First, you need a wheel polishing fixture. Rob the base from a 4 or 5-legged office chair, pop off the casters, then mount it to a small piece of 3/4-inch particle board for a stable base. There you go...a rotating polishing fixture just the right height. Pop the tire off place the wheel on top of the chair legs, loosely c-clamping it to each chair leg using a piece of rubber pad as a non-slip cushioning pad. Rotate the wheel slowly and center it by eyeball while tapping with a rubber hammer. It's pretty easy to get it right on the button, then snug up the c-clamps.

For mechanical removal of the powerder coat you need: (1) aluminum oxide-impregnated, nylon abrasive wheels in graduated grits starting with 120-grit, going upward to around 220-grit, (2) a 1/4-inch high-speed drill or flex shaft capable of at least 2500rpm, and (3) a round, random orbital sander with the same grit range sanding sheets.

Start at the edge of the rim with the 120-grit nylon wheel or random orbital sander, using combinations of all tools that best fit into the contours and features of spokes, etc. You'll notice the wheel starting to turn from the action of the wheel or random orbital sander. You don't want it to spin like crazy, but a slow turn for uniformity. This is easy to control by holding the wheel less than tangent to the wheel. Completely remove the scratch of a coarser wheel with that of the next finer. This is a "have to." All prior scratch must be removed by the next finer. Your last sanding should be done wet with a spray mist, rinse well, then wet hand finish with a 3/16 thick aluminum oxide sponge pad of about 300 or so grit for a flat, smooth finish. It will go quick, even though its by hand. We are not ready to polish and buff.

For polishing and buffing, start with a yellow, mill-treated bias cut 4-inch wheel using black emery. Alternatively, you could use a tight concentric sewn or spiral sewn buff. This is an aggressive compound so keep it moving, but it's darn sure quicker and better for these type contours than attempting to continue sanding with subsequently finer grits. You should see a satin-like semi-shine when you've taken the compound to its full potential. Rinse very thoroughly with Dawn dish detergent and water. Do not leave the slightest spec of residual compound or you will cross-contaminate the grits. I suggest using the cheapy throw-away gloves you can buy anywhere they sell paint. Wash your hands between operations as well to prevent transferring grit to the next polishing operation.

Shift to a white, bias cut buff (not mill treated) and use brown Tripoli [link is to product info at Eastwood] compound. Alternatively, you could use a concentric sewn buff sewn at 3/8-inch pitch or greater. If you take the tripoli to its full potential, you'll see a bright luster starting to appear. Clean with Dawn and rinse thoroughly again, washing your gloved hands as well.

Change to a loose sewn cotton muslin buff and use White Rouge [link is to product info at Eastwood]. Taken to its full potential, you will achieve a mirror luster. Keep the heat up while buffing. This compound removes no material, but will microscopically surface flow material due to heat and the extremely fine particle size of the grit. Clean with Dawn detergent and rinse once more. Get out your sunglasses.

You're going to have a garage or shop mess that nothing else slightly compares...unbelievable...a messy black, greasy, buffing dust everywhere and on everything. It's of a particle size that makes flour seem like gravel. To eliminate a lot of that at the source, use a box fan on each side of where your are working. Duct tape a furnace filter to the intake side, notching a slit for the power cord to exit. Remove the grills to up the flow. There's a ton of info you need to know that exceeds what is appropriate in this small space.

Unless sealed, bare aluminum alloy is going to be quickly oxidized by atmospheric salts. Do a web search on "Boeshield T-9." This is a product developed by Boeing now licensed by the 3rd party chemical processor/distributor. It's a spray on/wipe off material that's an extraordinary penetrant reminding you of spraying WD-40 on something. However, as a deep penetrant to both aluminum and ferrous substrates, it seals and retains the "wet-look" for months. Depending on coastal vs inland use, reapply every 6-9 months. Only takes a second; just spray on, wipe off. It's good for about 250F.

You can alternatively use "Alcoa Sealer." Do a web search and you'll find it. This product seals entirely differently in that it is an isopropenol/inorganic formulation that'a about the most flammable stuff on the planet. It's a spray on, water rinse product. The rinse is a critical part of the sealing process, so rinse extremely well. However, before application, the wheel must be bone, bone dry or it will streak. Also, I suggest doing this at 50% humidity or less and the product and wheel first stabilized to 70F or so. You need to know that the Alcoa Sealer will ever so slightly degrade a mirror luster. It's also good for 6-9 months, depending on coastal vs inland use. The Alcoa Sealer is actually intended for bare aluminum, commercial truck wheels. As truck wheels are exposed to enormous heat as a heat sink from hard braking, the product is good past 1000F, the melting temp range of aluminum, anyway.

You now have mega-buck, sealed, mirror luster, chrome-like wheels. Unless you've taken measures to control the shop mess, you no doubt fully agree that the best way to do this is with a pen and checkbook.

Hope this helps, Greybeard

Lynn M. Perry, Sr.
retired - Plano, TX

The simple way is to send them to the pros to be stripped or stripped and polished they should only cost 25 ea to strip you will spend a lot more than that to purchase strippers.

david brown
- high point n.c.

Post a question on a different subject.

 

Answer or follow-up on this subject (in non-commercial fashion).