Disclaimer: The content of this document relates to the Porsche 993 (911 1995 to1998) I am not a professional automotive technician and some of the opinions expressed in this document are just that, opinions, therefore, please feel free to use this document at your own risk. Many times a lot can be learned by simply watching qualified professionals work on your 993
Body & Paint Work - Seeing the age of these cars paint & bodywork is present on most examples.
For example, I am on my third rear bumper cover as cars have scraped and bumped my car while parked in the local shopping center. Cosmetic damage to parts that bolts onto the car is not a big deal as they can be replaced and restored to original condition, things such as hoods, doors, front ¼ panels, front & rear bumper covers.
Why Paint Matters – Having your car painted is a big deal as properly applied paint will last the life of your vehicle. Here is my rundown on the subject based on both working with paint shops and having personally painted both new and used bumper covers using commercial methods and materials:
One stage paint uses a primer and one or more topcoats that carry the color. Two-stage paints involve a primer, color layer(s) and a clear-coat top coat that provides the gloss. Contrary to Porsche’s own marketing literature, solid color 993 are in many cases painted in single stage paint, my 96’ Speed Yellow car is. If your car is painted with single-stage paint any repainting should be done the same way. This will require finding a restoration quality shop that is willing to do this as most shops will just use a two-stage paint on what is now just part of your car.
Shops like to use two-stage paint as all newer cars are painted this way, it is simpler to apply and when their paint system can’t produce a color match between panels they can feather the color layer of the paint when applying it to merge the dissimilar color of body panels. Once feathered they can overspray the job with a clear coat. With single-stage paint where the color and final finish layer are one and the same getting a good color match upfront is how it is done requiring skill and the flexibility in selecting a paint system that can produce a good color match.
Most higher volume modern shops will only use their in-house paint systems as it keeps their cost down and meets EPA requirements. Usually, these shops use acrylic high H2O solvent-based paints. These paints and their application are significantly inferior to the paint that came on your car and can fail in just a few years. Smaller restoration paint shops do not maintain in-house paint systems. Due to their lower volume of work they are not required to meet the same EPA rules so they can select from multiple paint system suppliers paint that will color match very closely and not exhibit adhesion issues as it ages and gasses out.
All acrylic paints, the most commonly used, are somewhat brittle. This can cause things such as clear coat peeling around edges, failing from UV exposure or paint cracking or flaking off a bumper cover with minor flexing. For most modern cars this is fine as the original owner will only own the car on average for less than five years after which the lack of paint durability is someone else's problem. The most durable and flexible paint is a two-part urethane sometimes called 2K, used with a catalyst. Once it hardens it is much less susceptible to damage from chemicals, weather, or UV rays. It retains its flexibility/adhesion and if applied with a proper compatible primer will outlast the car. It is available as both one and two-stage paint. Also, automotive paint technology has been advancing rapidly so paint chemistries and systems are constantly being updated suggesting a good discussion of the paint that will be used on your car is always a benefit with the shop you ultimately use.
Painting a new vs used bumper cover - Bumper covers flex. For this reason, using a 2K urethane paint is especially important. Also achieving good adhesion is a big deal. An odd experience I have had is that achieving good adhesion on a new replacement cover is actually more difficult than over spraying an undamaged used bumper cover. I believe this has to do with some of the plastic’s chemical components migrating to the surface of the part and creating a coating that is difficult for the paint to grasp.
Some new covers are also pre-primed, however, the primer in many cases is not compatible with the paint system being used so it must be sandpaper prepped and the part re-primed. I have used adhesion-enhancing sprays to assist in overcoming these issues. Even with these sprays getting the primer coat down right and achieving good even adhesion can be a challenge.
With used bumper covers where the existing paint has good adhesion resolves many of these issues as the plastic is encapsulated under the paint and therefore does not cause issues. In this case, the existing finish needs to be sanded to prep it for good mechanical adhesion and the proper primer applied to ready it for painting.
Beware of reconditioned bumper covers. Many have had cracks or rips repaired in them. This is typically done by using melt gun plastic to fuse and fill the crack. I have tried these products and found that although they can produce flawless repairs from a visual standpoint the repair is not as strong as the surrounding material. For this reason, using a reconditioned cover where the rip or crack repair extends to the edge of the part can result in a propagation point for future failure. The takeaway from this is that one should only consider a used cover if one can personally inspect it for edge rips.
A quick mirror paint gouge fix: I inadvertently put a deep 1/8” wide gouge line in the mirror housing of my single stage painted Speed Yellow 993. So deep in fact that it gouged into the white plastic housing underneath. To eliminate the gouge I took some leftover paint from the last time the car was painted and put a little in a metal cup letting it dry out into a thick pancake syrup-like consistency. I used a small artist's paintbrush and painted several coats of the paint over the gouge until it filled above the surface of the surrounding paint. I let it dry thoroughly between coats and then used 1500 or 2000 grit wet sandpaper and a water hose to sand the paint flush with the housing's original paint surface. Worked great. and It didn't take very long. Used care not to sand through the finish of the surrounding paint, It may be worth a try before committing to the expense of having a body shop overspray the entire mirror. The nice thing is the process can be repeated adding additional layers over and over until a satisfactory result is achieved.
Impact damage to a door jamb or in the rear quarter panel areas can profoundly diminish the integrity of the car and so should be carefully investigated on a car being considered for purchase. Also any serious front end or rear damage where the unibody was involved signals that you should not be considering the car. Such damage is identifiable by a competent body shop guy.
