Disclaimer: This procedure worked for me. I make no promises as to the longetivity of the repair, its safety, or effectiveness. This is for informational purposes only; you must make your own decision as to whether it’s a suitable procedure. Basically: if you break it, it’s your fault.

In order for the procedure to work, you must be capable of working accurately, with a quite high level of skill and precision. Do not attempt it if you aren’t 100% sure that you possess these skills.

This procedure is time consuming, including a significant amount of prepartion, which is essential for the job to work. Budget for around 3 hours of labour per wheel, plus the time required for painting, and leaving to dry between coats.

A tale of woe

After a couple of minor accidents with a kerb and with tarmac, the alloy wheels on my 2007 VW Jetta were looking pretty bad. One of the accidents was when I was trying to parallel park on a ridiculously steep hill in Glasgow; the other was when I was changing a tyre after a puncture, and ended up dropping the rim, face down onto the concrete. The first resulted in kerbing damage, the other resulted in stone chips.

The car has VW Atlanta alloys. These are made by painting the entire wheel grey, machining the visible surface with a diamond cutting machine (”diamond cut”) to bring the surface back to bare metal, and then lacquering the result with a clear lacquer. This is different to most alloy wheels which are painted in their entirety with paint, before being lacquered. The fact that it’s bare metal that has been lacquered makes them difficult to repair. Any filler will be visibly different from the bare metal.

I had them “repaired” by a supposed professional and asked for them to be diamond cut again; I was assured that this was possible. It seems that all he did was lightly machine the surface with a sander, before putting very low quality lacquer on. So after 18 months, they were looking appalling. Far worse than they were before I took them in to get fixed.

Diamond cut wheels are exceedingly pretty (I’ve only really seem them on Volkswagens and Mercedes), but unfortunately they aren’t particularly good at dealing with real world wear and tear. I therefore decided to go for a different approach, and to sand the lacquer back down to bare metal, to paint with silver paint, and then apply a clear lacuqer.

Materials

The materials I used are as follows

• 400 wet and dry paper
• 800 wet and dry paper
• Parcel tape
• Electrical insulation tape
• Halford’s grey primer
• 2 x Wurth silver German car lacquer
• 2 xWurth clear lacquer
• Plastic Padding Chemical metal

The total cost of all of the materials (which for me was sufficient for all four wheels) was around £50.

Cleaning

The first step, and absolutely crucial to the process, is to take the wheel off the car and give it a thorough clean. I used the bath, with a detachable showerhead. I used a washing brush to give it a clean all over, and a tooth brush to clean in the crevices. The wheel had sustained some petrol stains from over enthusiastic refuelling, so I used white spirit in combination with the tooth brush to rub this off – it took a fair bit of effort, probably about 30 minutes to have the alloy as clean as I wanted. I was very careful to not get the white spirit anywhere close to the rubber, and I used absolutely copious quantities of water to wash the white spirit away.

Again, I cannot emphasise enough how important it is to get this stage right.

Sanding down

Next, it was time to thoroughly sand down the lacquer, back down to bare metal, on the visible surfaces of the spokes. I used 400 grade wet and dry paper to do the majority of the work, using a small metal object as a sanding block, to ensure that the rubbing down was square. After the surface to be painted had been taken back to bare metal, I lightly sanded over with 800 grand wet and dry paper.

Filling in any imperfections

I next used Plastic Padding Chemical metal to fill in any imperfections. I obtained this from Halfords. I used the supplied spreader to apply quite a flush application, and then used 800 grade wet and dry paper to make it as smooth as possible.

The chemical metal ready to go.

The chemical metal applied to the imperfections. I was extremely careful to not allow any of the mixture to touch the rubber.

After this, I took the wheel back to the bath for a very good wash. I used kitchen paper to dry it off, before leaving it to fully dry off.

Masking

As I wanted to keep the original two-tone (grey and metal, or grey and silver) appearance of the wheel, and because I was keeping the tyres attached, it was essential that I did a very good job of masking the areas not to be painted. I started off by using flexible masking tape, pushed right between the surface of the rim and the tyre. This ensured that no paint got on the rubber itself.

I then used electrical insulation tape to mask the metal areas. I chose this because it is a lot sticker than normal paper-like masking tape,reducing the risk that the paint will run. It is absolutely essential that you get this step right. If after masking an area it doesn’t look like it’s done properly, do it again. I used parcel tape to fill in the gaps. I used additional parcel tape on the rubber to prevent paint touching it, before using more parcel tape and newspaper for additional masking.

After finishing, review all of the masking, and re-do any areas that could be improved. It’s quite time consuming, and it took me 30-45 minutes to do the wheel.

The wheel, with all masking in place, and ready to paint.

Applying the primer

As I was painting directly onto bare metal, I first applied a primer. As I know no better, I used Halford’s grey primer, which claims to be compatible with most kinds of paint. The primer is designed to improve adhesion between the metal and the final topcoat paint.

I applied one coat of primer. I allowed it to dry, checked for imperfections, before removing these, and applying a touch more primer in these areas.

Appying the silver top coat

I used Wurth silver German car lacquer as the top coat. It is imperative that this is applied very thinly, so that it does not run. Although it is tempting to paint large amounts at a time, this will cause a poor appearance, and it’s possible that the paint will run down between the masking and the metal. I applied three coats, leaving around 30 minutes between each layer.

I sprayed each spoke, sprayed the centre section, and then sprayed the rim.

Applying the clear top coat

As the clear top goat is going to be the thing exposed to the road and stone chips, it’s important to get this right. I chose to apply three top coats, allowing about 30 minutes between each layer. Again, the coats should be quite thing so that the lacuqer can’t run.

I removed the masking before silver and clear coats had fully hardered; around 20 minutes after applying the final top coat. This requires car to not touch the paint, as it is quite easy to damage it while it hasn’t hardened. This gives you an oppurtunity to remove any paint that has run, before it has fully dried (hopefully, if you’ve been careful with the masking, this will be minimal).

I then chose to apply a very light final clear lacquer spray to the entire thing, including the original grey areas. Of course, the masking around the rubber was still in place.

The final result

Although it’s not 100% factory perfect, the resulting finish is very good, and unless you’re looking at the wheel from about 10cm away, it looks pretty convincing.

After one year - updated April 2010

Seeing how they have fared after a year, including a very harsh winter, is the key test.

Although the car and wheels had not been cleaned for a long time at the time and so are filthy, here are some photos of two of the wheels. The others are in similar condition. All of the stains should come out easily. Crucially, the finish isn’t peeling of badly chipped.

Close up of a chip. It shouldn’t be had to do a localised repair here, just rub it down and repaint. This would have been impossible were they still diamond cut.