Got wheel issues?

I’d like to welcome a fellow Tasmanian Saab Car Club member here to Trollhattan. Drew has forgotten more about Saabs than I’ll ever know. He’s restored a magnificent silver 900 from a wreck. He’s currently restoring an old 99 into what will be an absolute showpiece (that story’s still to come) and has a black 99 Turbo waiting in the wings.

Drew was one of Dan Rotman’s Targa Tasmania crew and proved to be a valuable resource for the team with his superb running knowledge of the cars.

Drew’s given me the OK to publish here a piece that he wrote on refurbishing your wheels. One of the things I’ve always loved about Saabs is the fact that generally (OK there are some early 1980’s exceptions), they’ve all come with some pretty nice wheels as standard equipment. The daily scrapes can make them look a little tired, though.

The process described here is pretty simple and won’t cost much. I know – I’m in the middle of it right now with the Inca’s from my 99 Turbo. Enjoy.

There’s no doubt that curb-rashed alloy wheels can really detract from a vehicle’s appearance. Given that aluminium alloy isn’t a terribly durable material, and the costs normally involved in having even minor damage professionally corrected, it’s easy to understand why so many of our Saabs exhibit damaged rims after many years of driving. So, what to do? If you possess ample spare time and patience, a spray gun, and a general willingness to learn, read on……..

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Wheel damage
This can range from minor curb rash to major bends and cracks – and is not always outwardly apparent. Hammered-on wheel weights are also a common source of damage, often resulting in fatigue cracking on the rim’s outermost edge. Aluminium alloy has a tendency to crack rather than flex, which is why it’s always best to have any major-ish damage, other than mere gouges, professionally repaired on a wheel lathe. There are several specialist businesses in Australia who perform this task, and often quite cheaply. To have the outer edge straightened and machined, for instance, can cost as little as $30.
For relatively minor damage of painted alloy rims, such as centre gouges, curb rash, etc, Pyrmo produces a 2-part aluminium filler. With a curing time of approximately 30 minutes, and ease of sanding, it’s a fantastic product ideally suited to the repair of aluminium and other non-ferrous metals.

wheels2.jpg the Pyrmo filler. Easy to use. Click to enlarge.

Sanding and paint removal
Preparation is everything. Start by thoroughly cleaning the wheel with a suitable cleaner in order to remove any brake dust, oil or grease which may be present. If the wheel has been amateurishly repaired before, is chipped, or has flaking paint, then the affected areas must be removed in order to provide a solid base for the new paint. In this regard, there’s only one successful option – soda or bead blasting. Again, this is quite inexpensive – to remove the paint from the inner and outer surfaces can cost as little as $10 per rim. Sand blasting should be avoided, as the size of the abrasive can cause the wheel surface to become pitted. From experience, using paint stripper is virtually pointless – the paint film is thick, heat-hardened, and not easily removed. Not only that, it’s messy, hazardous, and time consuming to use. Stick with blasting.

For undamaged original paint, P400 wetordry, a grey 3M scotchbrite pad or a 3M superfine hand-sanding sponge can be used to prepare the surface for new paint. Any chips should be sanded out or filled. Filled areas should be sanded with #120-#180 frecut paper. This may be quite a time-consuming operation, dependant on the intricacy of the wheel’s centre pattern. Pity the Saab owner refinishing cross-spoke alloys!

Paint selection
There are two types of paint – acrylic and two-pack.

Acrylic paint dries by solvent evaporation, and is best suited to those with minimal spray-paining experience. It’s easy to use, fairly cheap, quick drying, and produces a good finish. However, it’s not overly durable, and prone to softening and long-term discolouration from brake-generated heat.

Two-pack paint, as the name suggests, requires the addition of a hardener for curing to occur. It’s very durable, produces a high-gloss factory finish, and covers far better than acrylic – not as much paint is required. However, two-pack is more expensive than acrylic, is more difficult to use, requires a dust-free application environment, is slower drying (in the absence of a baking oven), and is more toxic due to the presence of isocyanate in most hardeners.

Saab alloys are finished in two-pack paint, and oven-baked to provide a durable, high quality finish.

Whichever paint type is chosen, it should be ensured that the products used are all compatible, preferably produced by the same manufacturer.

Priming
First off, clean the wheel thoroughly with a suitable wax and grease remover or equivalent cleaning fluid. Allow to dry, and mask off the areas to be painted, if required. Use a good quality masking tape which is solvent resistant.

Bare aluminium must coated with etch primer in order to provide adhesion for the finishing coats. A 2-pack etch primer is best for this purpose, and can be used under both acrylic and two-pack paint films.

Most two-pack etch primers mix 1:1 with hardener. Two coats should be applied to all bare surfaces, and should be allowed to air cure for at least one hour before primer-surfacer is applied. No sanding is required. Approximately 500ml of mixed etch primer is required to completely prime four bare wheels.

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Primer-surfacer
The role of primer-surfacer is to provide a base for the new colour, and to fill any minor surface imperfections which may be present.

Acrylic primer should ideally be mixed 1:1.5 with thinner, and applied in accordance with the manufacturers recommendations.

Two-pack primer is generally mixed 3:1 or 4:1 with hardener, to which a small quantity (generally 5-10%) of two-pack thinner is added. Two to three coats are generally required to achieve coverage, generally applied 10 or so minutes between coats. Again, manufacturers guidelines should be strictly adhered to.

1 litre of primer-surfacer is generally sufficient to cover 4 wheels with 3 coats of material.

After one day’s curing, both types of primer-surfacer can be lightly sanded with P800 wetordry or a 3M ultrafine hand-sanding sponge. Repaired areas may warrant some detailed sanding. Any exposed areas of primer or bare alloy can be lightly spot-primed with the appropriate primer-surfacer. Following a good wash, a re-mask and the application of wax & grease remover, the wheel is ready for the final step – colour!

Colour Application
All Saab alloy wheels have clear-over-base paint. That is, a ‘clearcoat’ is applied over the top of a coloured ‘basecoat’. Acrylic and two-pack paints don’t differ in this regard, and are similar to apply. Approximately 1 litre of mixed colour is sufficient to cover 4 wheels. Similarly, between 500ml and 1 litre of clearcoat is required to complete the process.

Acrylic basecoat colour is generally mixed 1:1.5 with thinner, with at least 3 coats applied 10 minutes apart required to achieve full coverage. After allowing to cure for around one hour, two to three coats of clear should be applied according to the manufacturers instructions.

Two-pack colour is mixed approximately 1:1 to 1:1.5 with two-pack thinner, and applied in identical fashion to acrylic paint. If anything, it should be applied more sparingly to avoid ‘runs’ caused by slower drying times involved. After at least one hour’s curing, one to two coats of clearcoat are applied in a similar manner.

The refurbishment process is now complete! After a couple of day’s drying, the tyres can be refitted, and subsequently balanced with the addition of adhesive weights….. and the final result should look something like the spoked Saab ‘minilite’ wheel pictured – simply stunninng!

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Saab wheel colours
Silver metallic (most pre-1996 cars) – ICI ref# 7PC4B
Coarse silver metallic (1997-on) – ICI ref# 1737B

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