Thursday, September 16, 2010


Every person who sprays paint at cars has or has had disasters at one time or another; even the most experienced professionals get it wrong from time to time and, in some cases, there is no alternative to removing the topcoat and primer — and starting off afresh on bare metal. There is greater potential for things to go seriously and expensively wrong during the painting of the car than there is at any other time during the restoration. The whole process involves a considerable investment in paint, and all this outlay can be wasted due to mistakes during preparation, due to there being the tiniest particles of silicon in the atmosphere or dust blowing through a gap in the door, or to the paint being contaminated by water and/or oil from the compressor. There is a thus strong case for having the spraying and paint preparation of your Beetle carried out professionally, and the majority of people who do restore their own cars appear to take this option.
Some people prefer to carry out the preparation work themselves and to have just the topcoats sprayed by professionals. This approach is fine as long as the preparation is of the highest standards, because any shortcomings in the preparation are equally as serious as problems with the application of the topcoats. If you choose to prepare the car for spraying yourself and have the topcoats sprayed at a professional spray shop, it is worth asking the person who will be doing the work to carry out the final preparation for you.
Before starting spray preparation, do stop to consider whether the existing paintwork can be salvaged. If there is a good depth of paint then it is often possible to flat then polish the most unpromising finish and end up with good looking results.
The primary object of painting a car is to prevent the steel of the bodywork from corroding, which paint achieves by insulating the metal surface from the atmosphere. In order for the paint to achieve this result, it must be applied on to corrosion-free, clean, dry and grease free metal. If paint is applied on to metal which has started to corrode, however slightly, then that corrosion will spread under the surface of the paint. If paint is applied on to a contaminated surface, then one of two things can happen. Either the contaminant can react with the chemicals in the paint to cause blistering
or one of a dozen different problems, or the paint can fail to adhere properly to the metal, In both cases the paint will sooner or later lift from the surface of the metal and allow corrosion to begin.
The first stage of paint preparation is thus to remove all traces of rust from exposed metal, and to remove any contaminants (including earlier paint of types which are incompatible with the paint which you now wish to spray). In other words, the shell should be taken back to clean, bright metal. This can be achieved using emery paper and much energy, although the modern dual action and orbital sanding devices speed and ease the process so much that there can be few who would nowadays carry out this work by hand,
Previous layers of paint and primer do not necessarily have to be removed, so long as they are sanded down to provide a key for the new paint and to remove totally any traces of silicones or other contaminants which may lie on the surface. Also, the previous paint and primer must be of a type which will not chemically react with the paint which you intend to use. Problems can arise if you attempt to spray cellulose over other types of paint, because the powerful cellulose thinners will soften and possibly lift the underlying paint. Before buying your paint, therefore, ascertain which type of paint has previously been used and ask the paint mixing specialist which paint type can be used over this.
It is best to remove all chrome trim and windscreens from the car, and to thoroughly mask off the interior before you begin to spray paint. Screen removal is described elsewhere in this chapter; to remove the chrome trim, gently prize away one end with a blunt screwdriver or similar, then use the shaft of a small screwdriver to ease the trim off the clips.

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