Need Help Polishing aluminum Wheels.

[mattyp]

Hey guys, I'm new to this forum but I'm using the Caswell Powdercoating system now with much success.

Heres my situation. I have a set of 17" Racing Hart rims for my car that I would like to strip and polish to a mirror finish to help accent the podercoated brake calipers I've got on my car. I do not have a bunch buffer but I don't think one would be helpful in this situation since the wheel is so large and unweildy. I have both a 12,000rpm dremel tool (electrical) and a pnuematic die grinder. I was planning on buying the wheels and bobs (as needed) for use with my die grinder. The main concern with this is speed. I'm not able to controll the speed of the die grinder and I'm afraid I may cut too much.

What do you recommend the best tool for this application? Also, I was planning on buying the Jumbo variety pack of compounds but from what I've read I'll only need the black (a lot of it) for cutting and the green for buffing to a mirror finish. The wheels are aluminum but appear to have some sort of finish on them...possibly paint or enamel. I had planned on using a 70/100 medium glass bead to strip the wheels prior to using the compounds. I'm pretty good with a blaster so I won't cut into the metal. Is trhis recommended as a first step as opposed to sanding by hand? I'd really hate to do that when I can strip them completely with a bead blast in about 10 minutes.

Am I missing anything?? Any advice??

[mattyp]

bump

Bump! Still need help guys....

[skiddz]

Bead blasting the wheels is fine, but you'll still need to sand to get all the little nicks and scratches out. Bead blasting will not leave you a nice smooth finish for polishing. You'll still need to sand the piece before it ever hits the buffer.

I'd opt for a flex shaft attached to your buffer for the majority of the work. Hit it with greaseless compounds up to 400 grit, then wet sand by hand until you get a uniform finish and all visible scratches are gone.
Once it's sanded, wash it off completely. Any sanding grit left over will embed itself in the buff and scratch the hell out of the piece.

I've stopped using sisal wheels with emory (black) compound on aluminum. I now use a treated, vented buff with tripoli (brown) to start, followed by a tight spiral buff with green, then finish with a flannel or loose cotton wheel and white rouge. The sanding is the key. The better the prep, the easier it will be to buff and get that "bling bling" look you're after. Since stopping with the sisal/emory compound, my buffing time has been reduced and my results have improved dramatically. My sanding times have almost doubled, but it's worth it with the results I'm getting.

[mattyp]

great advise.

That is VERY helpful. The wheels have some curbbed spots on them so I'm hoping to smooth them out as best as possible after the sanding/stripping step.

Would you happen to have any pictures of the wheels you use? I can order the flex shaft tonight and I agree that should cut a lot of time off the job.

How long would you estimate it would take a newbie to do these wheels nicely? I'm just looking for an estimate.

Thanks!

[skiddz]

I don't have pics of the wheels, but the wheels I use I typically get right from Caswell. I use a 6" vented buff (sometimes I stack 2-3 together on the buffer) for the tripoli (brown) compound, a 6" tight spiral for the green and 6" loose cotton or flannel for the white.

I use 4" or 6" tight spirals for the greaseless compounds. (1 wheel in each size for each grit)

I also have a good selection of mini bobs for tight areas...

As for a time estimate, it's gonna take several hours for each wheel just to sand 'em. (Depening on initial condition of course) The more time you spend on prep, the better your result will be. About 75% of the time I spent on a part is sanding, 15% on the buffer and the remaining 10% is spent cleaning the parts between steps, changing wheels on the buffer and reapplying compounds. Patience and practice will get you the results you're looking for. Unfortunately, there doesn't seem to be one "magic "step that makes it all easy.

[mattyp]

great!

What a great, informative reply.

I was going to purchase a cutter/grinder that spins 11K rpms also. Is this excessive?? The problem with doing a wheel with a bench grinder is the size of the wheel makes it unruley and difficult to handle for any extended period of time. I need some way of working with it while it's lying down. I guess your idea of a flex-shaft would be best if you don't recommend the grinder/buffer.

How much of the Brown and White triploi should I order? Approximatly how long does a bar last?

Thanks again for such prompt and helpful replies.

[skiddz]

11k is going to be too fast... You want to get your wheel's surface feet per minute speed to right around 5,000 SFPM. A 6" wheel on a 3450RPM grinder/buffer will get you right around 5400 SFPM which is close enough.

I cobbled up a quick javascript wheel speed calculator a few weeks ago. You can check it out here and try out different RPM and wheel diameter combos.
Buffing Wheel Speed Calculator
(if it blows up your computer, it's not my problem. eheheh)

I use a flex shaft for wheels. They're too damned heavy to hold up to the buffer and I guarantee you you'll slip and ding the wheel somehow doing this. (Been there, done that more than once) Get a flex shaft you can connect to your buffer/grinder if you own one. A good heavy duty drill can be used as well. I use 4" wheels on my flex shaft for two reasons.

1) It slows down the cutting rate and gives you better control.
2) If the wheel catches on something, it won't wrench on your wrist quite as bad as a 6" wheel will. (remember, I use a 1hp 3450 RPM buffer. It's got a LOT of torque - A drill will probably not have enough "oomph" or RPM to push a 6" wheel)

I wrap the end of the collet with duct tape to protect whatever I'm working on. As careful as I try to be with the shaft, I sometimes get the metal parts in contact with the piece I'm working on. The tape helps prevent inadvertent damage.

As for compounds, I buy the jumbo bars and they last quite a while. I did have one PITA part a couple months ago that ate up 4 6" sisal wheels and half a bar of emory, but that's not by any means normal. (Crappy aluminum)

1 bar of each will do those wheels a half dozen times easy.

Feel free to drop me an e-mail to skiddz *AT* adelphia *DOT* net if you've got more questions.

[Pretender]

Polishing aluminum wheels

Hi, folks! Real rookie here. I am about to start polishing a pair of cast aluminum motorcycle wheels, and coulld use a bit of advice from the gurus.

The wheels are 18 years old, and have some sort of black/dark gray stains on them (probably from water, I'd guess). There are also some small pits on the outside of them in the area where the tire sealts. I'd like to remove them if it can be done without damaging the integrity of the wheels.

These particular wheels are often described as an Aztec Sun pattern, having x-shaped 'spokes' around a solid hub. Originally, the wheels had a lightly polished (very lightly) rim , and a similar light polish on the face only of the spokes. The face of the spokes is about 1/4" wide, and need to be polished. This presents a couple of problems, since the rest of the wheels (inside of the rim and inner surface of the spokes) is silver-gray powder coated, which I'd like to preserve because it looks cool, and it's original. The powder coating is in perfect condition. To perhaps better explain it, if you think of the wheels laying down, the horizontal surfaces are polished, and the vertical surfaces are powder coated.

What I need advice on is how to best polish the narrow ends of the spokes without rounding the edges. I assume I'll need something quite firm so that tthe wheel/bob/whatever doesn't press down into the space between the spokes and damage the powder coat.

Another problem area is (again thinking of the wheel laying down) the 1/2" wide vertical band that constitutes the inner diameter of the bead sealing area. Immediately under this band is powdercoat again, so I can't touch that.

What I'm looking for is some idea what tools would be appropriate for this job. I ordered what seemed like an appropriate assortment of felt bobs, but they seem to be way too hard, and don't pick up compound well when spun with a drill or a die grinder. I'm looking for a flex shaft I can hook to my bench polisher, as I'm sure that would work better overall to turn whatever I need to use to polish with.

Sorry for the length of this post! Sure wish I could post a picture, it'd make things a whole lot clearer. And my apology for spelling errors... I type very poorly.

[skiddz]

Got a pic you could share with us? I would think the felt bobs would work great for the "horizontal" areas if you can spin 'em fast enough..

[Pretender]

Skiddz,

I have some pictures, but I can't figure out how to post them here.

I have a pneumatic die grinder that is somewhat adjustable, 22000 RPM wide open. I tried that, but ithe bob bounces quite a bit. I'll try slowing it down.

Thanks for the reply, Sir!

[skiddz]

mail me one to skiddz AT adelphia.net and I'll see if I can come up with some ideas..

[Pretender]

mail me one to skiddz AT adelphia.net and I'll see if I can come up with some ideas..

On the way, Sir. Thanks!

I finally figured out how to upload a pic to my personal gallery, too! I'll update it with an 'after' when I'm done polishing them.

[skiddz]

I replied to your mail about an hour ago. Hope it helps.

[Pretender]

I replied to your mail about an hour ago. Hope it helps.

Skiddz,

Got it. I'm sure it will help. Thanks!