aluminum wheels

[marineblue]

i"m in the process of sandblasting a set of painted aluminum wheels after that i want to polish them and clearcoat if i remeber correct their is a certain type of polish i need to use is this correct? because if i use any type of polish the clearcoat won't adhear to it could someone suggest a good polish thanks

[sswee]

From spending a few years in paint & body, try to stay away from polishes with silicone. It kills adhesion and causes fish-eye. Most buffing and polishing compounds made for paint & body or polishing metals are ok. The ones to watch are the ones meant to maintain the shine after it has been achieved. The main concern will be making sure they are super clean before coating. You'll have to check with the manufacturer on their clear to see if it will go over bare aluminum, not all will and not many will last a very long time. Don't be suprised if you run into alot of pitting when you start sanding. It's normal in cast aluminum.

[mpierich]

Originally Posted by sswee

. Don't be suprised if you run into alot of pitting when you start sanding. It's normal in cast aluminum.

Boy are you right about that. I just did a set of brand-new aftermarket Cobra valve covers. The pores were so bad I kept sanding thinking I hadn't gotten the rough-cast surface leveled. Makes it tougher to get all the scratches out too. I hate to disappoint customers like that, but nothing to be done about it besides copper plating and resanding, then chroming it.

[marineblue]

thanks for the reply. i don't think i will have a problem with pitting .because parts of the wheels are already polished from the factory. they are 05 dodge hemi wheels i like the style i think they would just look better polished and i think chrome plating would be to shiny. what do you think?

[marineblue]

thanks for the reply. i don't think i will have a problem with pitting .because parts of the wheels are already polished from the factory. they are 05 dodge hemi wheels i like the style i think they would just look better polished and i think chrome plating would be to shiny. what do you think?

[fxstcguy98]

I think what they are trying to tell you about pits is that cast aluminum has air bubbles in it. When you start to sand, you may uncover some of them, then you have to keep sanding until those are gone and hope to God you don't get into more. Sometimes you find pits, sometimes you don't, that's just the risk you have to take. And be prepared to do a lot of work, the blastprofile from sandblasting can be hard to get out sometimes depending on the hardness of the alum alloy. You would be further ahead to strip the paint off chemically so the underlying surface is smooth to start with. That is of course if the wheels don't have any knicks in it that you would have to sand and polish anyway. Good luck

[sswee]

Too shiney? What's that? I didn't think there was such a thing. LOL You need to go with what you like. I hope your lucky enough not to run into a bunch of pits but don't hold your breath. Unless you have billet rims there is a pretty good chance you'll hit a few. I've machined precision stainless castings, which are suppose to be high quality, and they have pits. Good luck and let us know how it goes. SS

[Gerarddm]

Take it from me and DO NOT SANDBLAST to remove old finish. Use chemical strippers. I sandblasted a set of Cromodora Daytonas for my '81 Fiat Spider and I had the devil of a time sanding them back down and then polishing. I would have been many hours ahead of the game if I simply stripped them.

Now- having said that, I have new problem. The parts of my wheels that I did not polish, but simple remained sandblasted, are now showing pitting and corrosion, despite simply being in my house for the past few months. What could be causing this- and how do I fix or better yet STOP it??

[sswee]

Gerarddm,
Hard to say without seeing the parts, but more than likely high humidity combined with contaminates impregnated into the parts by sandblasting. You should be able to stop or at least retard the problem with some WD40 or light weight oil to keep the air out until they can be buffed out. Any kind of corrosion or rust requires oxygen and moisture to occurr. SS

[berndog]

I would suggest as well,,,DO NOT sandblast,,I polish Alcoas everyday,after the frame of the truck has been sandblasted & painted,,it adds pits in your aluminum,& creates a nightmare.