April 2014

3 April 2014

Shiny things

As promised in the March entry, this post is all about wheels and tires.

The story properly starts last year at this time. Last April I spent some time repainting the wheels to simulate the way the earlier cars' wheels were accented. The results back then weren't perfect, but it confirmed that I did prefer the classic trim paint treatment over the all-black center that Porsche used from 1978 on. My plan was to do something similar but better when I replaced the tires someday.

The "someday" for tire replacement turned out to be this Spring. And I've laid more than a few different plans over the past year for what to do with the wheels. Replace them with bigger replica wheels, powdercoat them, polish them, etc. But in the end, I decided that the wheels I had were totally fine, all they needed was refinished. And if I was going to spend any time and effort on refinishing, I may as well bite the bullet and do it right—anodize them just like the factory did.

The classic Porsche alloy wheel was made by a German foundry, and the wheels are known today by the name of the foundry, Fuchs (German for 'fox'). They were originally developed as 15x4.5 size wheels for the original 1967 911S, and continued getting larger over the years as tire technology changed. They are forged aluminum, not cast as are most alloy wheels. Therefore they are relatively light weight, but quite strong.

The other unusual bit is that the Fuchs wheels for Porsche (Fuchs has made wheels for other German cars over the years as well) were anodized rather than polished, painted or un-coated. The anodizing process over the top of a polished aluminum finish gives a very durable, bright, but soft-looking finish.

Re-anodizing wheels is a complex, labor intensive process, so I tried to find a cheaper alternative that would give similar looks. But in the end I decided I wouldn't be totally satisfied unless I did it right.

I began by borrowing a spare set of wheels with tires from Adam, one of the local PCA members. I had the old tires removed, and shipped the wheels to the shop to be re-worked.

The first steps are to strip all existing finishes, both paint and existing anodizing. After two different chemicals for the paint, and a third stripping process for the old anodizing, this is what my wheels looked like.

Porsche wheels picture

Once stripped, the areas where the anodizing will be exposed must be polished. The shop that did my wheels uses a 5 step polishing process. Here they are, ready to go into the anodizing tank.

Porsche wheels picture

The anodizing process involves a big vat of acid and a mild electric current, which causes a chemical reaction between the aluminum and the acid and 'grows' a thin translucent coating of very hard aluminum oxide over the entire wheel. The coating is similar chemically to the synthetic sapphire used in watch crystals.

At this point the wheels are ready for accent paint to be applied. I wanted to do that myself, so the shop shipped them back to me. Here's what one looked like after I unboxed it.

Porsche wheel picture

Things get simpler at this point. Paint prep consisted of a quick cleaning and masking the areas to be left unpainted, as seen here.

Porsche wheel picture

Apply paint, and remove the masking tape.

Porsche wheel picture

And that was the look I was after, just like Porsche wheels looked like when I was in my teens and 20's.

The hard part was done at that point. I dropped them off at the tire shop to have a new set of tires (Michelin Pilot Sport A/S 3) installed, and bolted them onto the car.

Porsche picture

Continued in June...