painting rims?

[zman525]

My polished aluminum rims are all scratched and see to be near impossibly to clean up... is there any type of paint that i could use to bring some life back into them...? not necessarily a clear coat but i think i was gunna go with black because i want a whole yellow and black color scheme on my Z. any ideas?

(theres a pic of the rims in my gallery)

[BD240Z]

I've refinished a couple sets of wheels. I thought the process was simple and the results were pretty nice.

I used a silver metallic wheel paint and clear, the clear was catalyzed. I got the paint from the local auto paint supply house and I used the Preval throw-away sprayer to do the job. When the clear dried, the wheels were pretty smooth and this really helped when it came time to clean them. The brake dust and dirt washed right off. The clear held up and showed no signs of cracking or flaking for over 5 years, I then sold the car.

The wheels for my 240 are aluminum also and everything I've tried has failed in cleaning them up. I'm going to have them sandblasted and then I'd like to apply a clear coat with a low gloss/mat finish. I need to talk to the PPG guys and see if this is possible.

Good luck with your effort.

[280~Master]

Which rims are you talking about the AR's or the 5 slots?

[JimmyZ]

If the scratches aren't too deep you can sand then polish them out. This is made easier with scotch-brite/velco discs that fit 4-1/2" angle grinders down to drill size implements. The smaller version for use with a drill is what you'll end up needing for curves, detail work, etc.

Here's a link. Check out the Surface Conditioning Discs (Scotch Brite not aluminum oxide)

http://www.use-enco.com/CGI/INPDFF?PMPAGE=149&PARTPG=INLMK3&PMITEM=990-1302

If you can sand the scratches out then progess to 220 -320 grit paper. Switch to Scotch-Brite to get overall and any stray areas. Hit one last time with 400 grit then whip out a buffing wheel and progress through the various grades. Finish with a good metal polish to final polish and protect. You can easily get a mirror finish this way.

IF you decide that you need to paint them then you'll need to acid etch the rims before priming OR you can use an etching primer. Ideally you'd want a really tough paint like Imron. Spraying this requires a fresh air mask as repirators won't protect you from it.

Sending the rims off for powder coating is another possibility. I'm not that crazy about powder coating though.

My 2c

Jim

[Cruez]

Sending the rims off for powder coating is another possibility. I'm not that crazy about powder coating though.

My 2c

Jim

Just curious.... but what is wrong with powder coating??

[JimmyZ]

I should have clarified that my aversion to powder coating rims was due to them being die cast. (more later)

On flexible itmes such as pipe I've had it chip off in big chunks before. (Nope, it wasn't me that applied it) Imron's shine/luster would be better unless someone wanted a less reflective appearance. I'm just going on what I've seen at my local powder coating shop. I realize there are several powder formulas, each with unique properties. Maybe I've just not been impressed with what my local shop is doing.

What I'm getting at is that I have to wonder how well it would adhere to aluminum rims over time. (Heat cool cycles when brakes are used etc...) I imagine something a little more flexible like Imron would adhere better on an application such as rims. (Just use tape weights) The comment wasn't made to slight powder coating but rather it's use for aluminum die cast rims.

I machine and cast my own aluminum parts for various hobby projects. Some of the more critical stuff I send off to be heat treated. It is my understanding that Die Cast ally can be damaged from heat treating due to air pockets entrapped in the metal. I know it's only 400 degrees but it's better to be safe. Yes die cast can be heat treated if porosity and other factors are controlled.

I've known a few friends that used powder coating for their steel rims (Jeep rims) with no probs.

This is all MHO of course and my2c

Jim

[Arne]

Powder coating works fine on aluminum wheels, if it's done properly. I've seen lots of powder coated mags that have done nicely for years.

[Cruez]

If the powder was done correctly, it shouldn't have flaked off.. I have done periodic tests on my powder jobs with a hammer and it hasn't flaked yet.

The only time you need to be a little more careful is with alloys that are needed for strength, such as billet wheels on a cycle or car. If there is a safety concern, I don't do the part.

Cast aluminum and iron need to be outgassed before coating to get a good finish. I outgas parts that are cast (or I suspect are cast and machined). It doesn't hurt the metal its just a precaution to get a nice finish.

[JimmyZ]

Yeah I must have received some improperly baked/applied stuff. The coating was exposed to chemicals on occasion. The tubular steel also flexed a little. I think they didn't take the flexing into account when deciding which material to use.

Rims are mostly die cast but other methods can be used. It's possible that my old five hole mags were sand cast then machined. (Petrobond cast not greensand) This type of casting wouldn't mind heat.

The problem with die cast is the voids. Heat the metal and you can cause stresses which become cracks. I'm not saying that you can't powdercoat mags. It's just a possibility that a crack might develop and cause a part failure later.

As an example of hidden voids here's a pic of a hastily done plaster cast aluminum part. (Desk deco for a friend) You can really see the voids where gas was trapped. Machining exposed the voids.

Nice site Cruez. I'd have you do my powdercoating before the local guys anytime.

[zman525]

thanks a bunch for the info. guys i think im goin to see how they clean up with the ways mentioned above, and if im unsatisfied by the look i will paint them. BTW they are the AR's.