A lot of you are misguided with regard to paint. Saying that single stage lasts better than bc/cc, or vise versa, is a weak generalization. Paint's durability is dependent on a few key things. The particular chemicals you're using, the application, and the preparation. The few P cars of the late 80s/early 90s that did get single stages were mostly done using Glasurit 21 line. Glasurit 21 line no longer exists, and has since evolved to 22 line. I can tell you from my personal experience that Glasurit 21 line is the finest, most durable single stage I have personally ever seen. In fairness of the 22 line, I have not yet seen its durability tested on 10+ year old cars the way that I have with its predecessor.

Whether you're discussing single stage or bc/cc, you're essentially talking about the same thing. Both are urethane. Think of single stage as clear coat, only also including the color pigment.

Now it gets down to chemicals.. If the choice is Nason bc/cc vs. Glasurit 22 line single stage, then I would suggest the single stage option.. If you want to see the durability of Nason's clear coat, just look in the direction of a neighbor's car that was sprayed at the local Maaco a few years ago. If the debate is Glasurit 22 line vs. 55 line, you'd be foolish to expect the 22 line to outlast its bc/cc counterpart. With single stage paints, color fading generally occurs faster and is more pronounced. With base/clear, the pigment is better protected because it is actually beneath UV rays and weather elements.

It really is all about the chemicals. Hope this is helpful.

 

If you've got problems with the clear coat peeling or other wise failing after only four years, then either you've got low quality paint, paint that was applied wrong, bad prep, or a combination of everything.

Dunkelblau is a 2 stage paint. I know because that was the color mine was painted when I got it.

 

I am watching this with interest as my Dunkelblau is in desperate need of a repaint.

I get conflicting information, it seems some places are 'geared' up to spray Bc/cc (more commonly used these days) however the single stages on old hotrods that ive seen appear to be durable and can be buffed ..

But at the end of the day, it's the skill of the painter, prep, and chemicals used that determines the outcome.

 

Personally, I have a nearly naked suspision the the main problem with pealing clear coat in just a few years after the new paint job has been applied, is in the application. I have myself have not painted a Porsche for several years, but I have been doing quite a bit of study on doing one or more of my 928s in the near future. In the course of that study I have learned that one can apply several coats of paint on a car in succession, but that the succession needs to be fairly rapid in terms of each one following the previous. The material I have read suggests that the successive coats should be applied just after the previous coat has "flashed off," but if you wait longer, especially like overnight, the previous coat must be wet sanded first, or the next coat will not stick properly.

That also applies to the application of the clear, but you cannot apply it over a sanded color coat and still retain the gloss on the top of the previous color coat. I think that means that at least the first clear coat must follow rapidly after the last color coat. Otherwise it will not stick well. It will probably seam to stick ok for a few to several years, long enough for your paint guy to be gone or blame it on something else, but not as long as it is intended.

I suppose that if you don't have time to do all of the clear, you must at least do one coat of it, then you can sand it out the next day and finish up the rest of the clear in quicker successive coats.

I think the problem is that too many shops will short cut this procedure--and I have recently seen shops do this--and simply do the color coats one day and then wait even more than a day or so and do the clear coats right over the cured color coats. They still look really nice, especially after they are wet sanded out and polished, but since the clear coats are not properly bonded to the color coats they are going to peel prematurely.

What I suggest is that if you farm you 928 out for a paint job you should police the situation very carefully to see that the paint is all applied in rapid succession with no delay between the color and clear, and none between the color coats without intermediate sanding.

Just my thoughts.

 

Jerry, most of what you've said is correct, but it doesn't pertain to just Porsche vehicles. So yes, the main adhesion problem with clears stems from improper application (waiting too long or not waiting long enough), insufficient quantity of product applied, or the use of cheap materials that simply don't last as long as the better stuff.

 

Thanks for that; but I thought everything about Porsches was different from everything else.

 

Jerry, many paint systems allow many hours before you *must* apply clear over base. Yes, with clear, you must apply successive coats as the clear is chemically accelerated. Once I begin painting a car, I do not stop after base application as others do. If I begin painting, I remain committed until it la complete. Just my preference. Letting a car sit for much time between base and clear is just asking for trash.

 

As an automotive painter, I would agree with almost all of the above but wish to elaborate. Porsche used glasurit paint (made by basf) all throughout the '80's and most of the 90's. The change was made to 22 line in the '90's so there are plenty of cars with close to 15 year old 22 line paint. All solid colors were 21 line, all metalics were base/clear (54 line). Solid colors were not available in 54 line. The only way to clearcoat 21 line was with an additive. The change was made with the 55 line to make solid colors base/clear. 22 &55 line are both polyurethane paints. The clearcoat itself doesn't protect the color from fade. Its the UV protection in the clear that protects from fade. I use glasurit exclusively for Porsche's, its the best you can get. Porsche, Ferrari and Lamborghini have all used it. Cheaper clears do not have the same level of UV protection and will yellow and oxidize easily. I only use a single stage on a car I need to be period correct. Clearcoat peeling is improper prep, incompatible materials,improper application and/or cheap clear. Different types of paint have different hardness levels. Polyurethane is the hardest. Its more durable but harder to polish. You'll have to Polish it less. My advise is to pick a good shop and good material and you should be very happy.

 

I agree. Just to clarify, I think you mean to say that 55 line and Diamomt alike are polyester basecoats. Not polyurethane. I also agree that polyester basecoats are incredibly durable.

I have not personally used 22 line and had the chance to see it years later. That is why I didn't feel comfortable speaking to its longevity.

 

Good catch. I meant to say 21,22 and the clear for 54&55 line are polyurethane s. Very durable. Superior in every way to lacquer,enamel and even standard urethanes from other manufacturers. They're not healthy for painters but great for cars. 22 line is just as good if not better than 21.

 

The biggest problem with paint failure is prep and application. On the application side, topcoating too fast or applying too many coats traps solvents. These solvents try to evaporate through the layers and if the topcoat is too thick or dries faster than the bottom, the solvents will break the adhesion between and the topcoat will bubble and Peel.

 

I think you and I would probably agree that many here on RL have a mistaken confidence in single stage paint because of how well their cars held up with 21 line, originally. The reason for the paint holding up so well originally had more to do because of the chemicals used, not just that they were single stage on solid colors. As we say around here, "the bird is the word." If you insist on using single stage because it was original, then use Glasurit. Don't expect the same longevity with other single stages.

 

I agree. The same can be said for base/clear. I would use a glasurit single stage over a lesser brand base/clear any day. The better the paint, the better the look and longevity, given proper preparation.

 

Does anyone know if the petrol blau metallic in 79 was single stage of b/c?

 

B/C
Steve