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Part restoration guide

Ford Fiesta Mk3/3.5 > Technical information > Part restoration guide

I am aiming to restore every component on my car to as new, or better than new standard - and this includes underneath and the engine bay. Most people only notice the exterior appearance of a car, and as such this is the main focus of their cleaning. But have a look underneath of a car only a few years old and already surface rust will be appearing on most suspension parts.

Even though the parts I am restoring were only a few years old, it surprised me how badly time and the elements had affected them. The rust was quite deep on the more exposed suspension components. I will explain to you in the following paragraphs the various methods available to bring these parts back to factory, or better than factory, condition.

DIY

Sandpaper and Metal paint

If your car is not going to be used for show, but you want to keep it in top condition, then I think this is the best option available to you. This will be the cheapest method but will not produce professional results.

Acquire varying grades of emery paper some spray primer and a tin of metal paint. Sand down the required part using gradually finer grades, until you expose bare metal. An optional step to take is to prime the metal before painting, this is not a requirement for *propriety brand* but will give longer lasting results. Spray cans are best here - this provides a smooth, even finish and gets into difficult places easily.

Next step is to paint the part in a colour of your choice.

Professional preparation

Shot blasting

This is the first step in restoring your part, be it steel or sometimes, but rarely, alloy (not wheels). A very powerful compressor is linked to a blasting gun, which works basically like an airbrush. Air is passed over a canister holding tiny metal granules which are fired out of the gun at high speed. Upon contact this mixture remove removes a thin layer from the metal taking any loose scale rust with it, leaving exposed metal.

This is a perfect key for any coating you may wish to apply.

Galvanizing

Galvanising is basically applying a thin coat of slow-oxidising metal on top of iron or steel to provide corrosion resistance. The most common form is hot-dip galvanizing - this is where your part is immersed in a bath of alloy which electrostatially sticks to the metal, coating every surface.

For the ultimate in protection Galvanising can be combined with powder coating

Etch priming

I'm not sure exactly how this works but some substance is applied land leaves a surface that is a perfect key for every available finish. The coating leaves a yellow tinge to the part but can be seen through, and even welded through.

Professional finishing

Bead blasting/ Vapour blasting

This may sound like it belongs in the preparation section, and it is essentially the same as shot blasting. The difference is small ceramic beads are used instead of metal granules. This method brings a perfect shine back to alloy components such as gearboxes and cam covers. The downside is that once the alloy comes into contact with water again the same thing happens that you were trying to remove! This method will not leave a suitable surface for Zinc plating or Anodising.

Vapour blasting is a very specialised job and is used to give a smoother finish than bead blasting alone. This method uses beads and water vapour together to create a very smooth, chemically clean finish suitable for Zinc plating or Anodising.

Powder coating

This is a very durable finish, and one which I think should have been utilised by manufacturers in the first place! To start with the part in question (which has to be all metal - reason given later) Is shot blasted, providing a perfect key for the powder coat.

Next a good tradesman will bake the metal part to 'sweat out' any moisture left in, usually around welds (this is why only metal parts can be powder coated!). While still hot, a dry powder is blown onto the part which electro statically sticks to it. Every nook and cranny can be covered due to this method of application, unlike conventional paints which only reach the parts you can put your brush/spray into.

Finally the part is put into a very high temperature oven to bake the coating on. A huge range of colours are available in matt or gloss and my local powder coaters even do pearlescents and other effects. This method will provide you with a concourse standard finish.

Zinc plating

If you look in your engine bay you will see some parts that are like a transparent gold colour. This is Zinc plating, on new cars the brake calipers, Steel nuts and other small steel parts are plated, providing a thin barrier against the elements. This is not a very durable finish as it will fade after a few years and let the metal underneath corrode. However if you are entering your car in a show then this is a method of bringing those parts back to factory condition.

Only steel/Iron parts can be Zinc plated, and the first step in the process involves immersing the part in an acid bath to ensure it is perfectly clean. The next step is to electrostatially apply the Zinc in either gold or bright silver.

Chrome plating

This is a very expensive finish, but is arguably one of the best. Not many cars feature chrome plating from the factory - it is usually used to enhance the appearance of a show car.

There is an immense amount of preparation work involved in this finish, and like paint spraying any imperfections at this stage will show in the finished result. The preparation takes the most amount of time as the chrome plate itself, contrary to common belief, is not actually shiny, but a hard transparent layer. The chrome plate simply seals in the polishing work done underneath, and is applied electrostatially.

© Mark Stewart, Tuesday 15th June 1999
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