1972 Rust

[Tom F2]

Originally Posted by RWebb

what page of the FSM discusses the Karmann built cars?

Page SB 38 or 39, under special instructions for welding on galvanized metal. I believe that the "excluded" chassis numbers are all of the Karmann built cars. The translators at the factory called the zinc coating "galvanizing," but they also called the speedometer angle drive a "tachometer drive," so I stand by my earlier comment about the zinc coating process.

If you read in Frere's book about the challenges of the switch to the zinc coated metal, it makes sense that Karmann didn't do it. Probably the factory wanted to control the process in house. Lucky for those of us with Porsche built 2.2s.

[RWebb]

well, it sounds like a reasonable guess but I wouldn't put it as established fact

one could test your idea by examining a reasonable # of chassis from Karmann


re: "t's a hot dip zinc coating, not an electrolytically applied coating, so it's not really "galvanizing," to the best of my understanding."

When I look up galvanize, the usual definitions _are_ a hot dip process. Frere and others talk about Thyssen steel. I have also seen people claim that Thyssen steel was better than galvanizing and was a process that followed early factory attempts at galvanizing, but have never seen sources cited for those claims. However, it can be inferred by comparing various statements.

Here is what I was able to assemble from published sources:

Galvanizing on Porsche 911s - A History

[Tom F2]

Originally Posted by RWebb

well, it sounds like a reasonable guess but I wouldn't put it as established fact

one could test your idea by examining a reasonable # of chassis from Karmann


re: "t's a hot dip zinc coating, not an electrolytically applied coating, so it's not really "galvanizing," to the best of my understanding."

When I look up galvanize, the usual definitions _are_ a hot dip process. Frere and others talk about Thyssen steel. I have also seen people claim that Thyssen steel was better than galvanizing and was a process that followed early factory attempts at galvanizing, but have never seen sources cited for those claims. However, it can be inferred by comparing various statements.

Here is what I was able to assemble from published sources:

Galvanizing on Porsche 911s - A History

I had missed the bit about the change to Thyssen steel. I stand corrected on what galvinizing means. The original definition of "to galvanize" meant to pass an electric current through, but the word has acquired additional meaning, and now refers to any zinc coated steel or iron, by any process. Clearly, I have to take my recreational reading out of the 19th Century! By my statistically untested observations, the Karmann bodied cars didn't have the zinc coating, whatever we call it. The chassis numbers listed in the factory manual are perfectly clear, about this, at least to me. Every chassis number with a sixth digit '2' was excluded from galvanizing, i.e., 1970 models T and E with a sixth digit '2' and similar 1971 models T. I think that means every Karmann car. Given the special welding techniques needed, it makes sense, too, that Karmann would not have made galvanized paneled cars.

[RWebb]

it makes sense - think I'll add it as a maybe to that thread

[123steve909]

wow i got full marks on the rust, everywhere listed is where mine is showing rust!

Do i get a prize?


anyone know why the cars rust at point 19 as i can see no reason why mine is rusty there

cheers
steve

[dtw]

The rear glass corners? Yes, the glass's seal dries out and shrinks, allowing water to get in underneath. This starts the rust cycle...

[TVRLOTUSTR3]

A somewhat happy ending. I bought the car and there really isn't any rust. I had it on the lift and looked picked everywhere. The P O said it had not seen a drop of rain in over ten years. The bad news is I got hit by a bicycle and put a big dent in the left front.