Most classic cars have seen a lot - whether on the road or in workshops. Perhaps they have already been restored with more or less meticulous care, or perhaps they were repaired many years ago after a bump or rust damage "in keeping with the times". In any case, there are often surprises hidden under the paint in the form of other old layers of paint, filler, rust or repairs that are in keeping with the period.
If you want to be on the safe side when restoring a car in such cases, it is best to opt for a radical treatment. This involves removing all the old layers of paint and filler from the bodywork - creating a perfect basis for the subsequent restoration.
The company meier.rafz in Rafz in the canton of Zurich is a specialist in this field. Managing Director Didier Lengacher believes it is important to remove paint and rust from the bodywork gently yet effectively: "Sandblasting puts mechanical stress on the sheet metal and many angles in the bodywork are not even reached. With thermal paint stripping, the sheet metal has to withstand 400 degrees and there is a risk of deformation. That's why we opt for gentle chemical paint stripping and rust removal. This results in no warping and no metal removal."
The car bodies spend around four weeks in Rafz. They can be delivered with or without advance notice. All attachments and removable body parts, such as fenders or hoods, should already be removed. Thermal insulation and the like must also be removed.
The next step is to ensure that the fluids can drain away again during the immersion baths. If there are not enough holes or none at all, holes are created. They can be used for cavity sealing in a later phase.
For the paint stripping process, the vehicle is first carefully clamped in a special rack. The bodywork is immersed in a paint stripping bath for around 48 hours. Heat and solvents are used to remove the paint layer. The add-on parts are stripped separately.
The bodywork is then transported to the spraying area, where it is cleaned and freed of paint residues using high-pressure water for several hours. The filler is removed manually. This is followed by a second pass in the paint stripping bath to remove the remaining foreign material, after which everything is washed again and the cavities are rinsed.
This is followed by a 24 to 48-hour rust removal phase in another bath. "A special phosphorus-based solution breaks down the rust without attacking the healthy sheet metal," explains Didier Lengacher.
After this treatment at the latest, the true condition of the bodywork is revealed... Areas of sheet metal that have been attacked by rust often become pitted - this may look somewhat devastating at first glance, but it is a good basis for restoration. To prevent the rust from attacking again immediately, rust removal is completed with a further immersion bath for short-term rust protection treatment (iron passivation).
Then there are two possibilities: Either the bodywork and the separate parts are handed back to the customer immediately after drying, or an optional long-term rust protection is applied. This is a wash primer. "In our experience, a body is better protected with this than with an electrolytically applied CDP primer, for example. We work manually and very carefully. The aim is to protect as many stripped areas as possible with the primer. This requires a great deal of experience," explains Didier Lengacher. This is particularly important in cavities, and not just in sills, for example, but also in the struts on hoods or trunk lids, water tanks and other areas. "We have a whole set of lances for the different areas, with which we can reach almost all places," explains Didier Lengacher.
Long-term rust protection is particularly useful if the restoration will take a long time. The wash primer offers good protection during the restoration period and also enables welding work.
meier.rafz treats around 100 car bodies per year at its plant in Rafz and is delighted with the good reputation that its work enjoys beyond the country's borders.
Further information can be found on the meier.rafz website.
