Year tubs were Galvanized?

[ARCSinAK]

I have a 70T project wanted help recalling the year Porsche galvanized the tubs, I'm thinks about cutting a complete floor section from a galvanized tub instead of piecing in resto panels?

Thanks for your time-
JS

[Geronimo '74]

1976 iirc

[db_cooper]

In the training program at Porsche, we were told that 1974 was the first year for galvanizing. There were some special welding/repair techniques for the galvanized metals, required different methods from the old steel repairs.

I don't recall what those techniques were.

Seems like by 1980, there was a galvanized body on display in front of the offices in Zuffenhausen. It was in the weather 24/7. It never rusted.

Wonder how long it was out there? 1990..or longer?

[Bill Verburg]

Originally Posted by db_cooper

In the training program at Porsche, we were told that 1974 was the first year for galvanizing. There were some special welding/repair techniques for the galvanized metals, required different methods from the old steel repairs.

I don't recall what those techniques were.

Seems like by 1980, there was a galvanized body on display in front of the offices in Zuffenhausen. It was in the weather 24/7. It never rusted.

Wonder how long it was out there? 1990..or longer?

The floor pans and welded inner body panels were galvanized from at least '72, It was obvious what was galvanized and what wasn't from all the pin holes seen when I tore the car apart.

by the introduction of the '76 models all body panels were Thyssen double sided galvanized steel except the roof, by the end on the MY76 run even the roof was galvanized.

Porsche built several unpainted '76 MY cars and had them on display at the factory from the summer of '75 at least through '80.

[gamin]

You have a 70T like I do. You do not have any galvanized panels in your car. Zero.

[ejp]

Originally Posted by ARCSinAK

I have a 70T project wanted help recalling the year Porsche galvanized the tubs, I'm thinks about cutting a complete floor section from a galvanized tub instead of piecing in resto panels?

Thanks for your time-
JS

There is a great thread about what was done on what parts when here:
Body Galvanizing in Porsche 911

The relevant meat from the post:

Originally Posted by randywebb

This is a controversial, rumor-laden topic -- here is what I was able to find from sources that should be authoritative. Note the weight tidbit found -- so the body shells didn't really add too much weight because of the rust-proof steel per se.

Thyssen steel = steel with Zinc layers on both sides; thickness of the Zinc layers varied from 10 um to 20 um, depending on exposure conditions (Frere, p. 201)

1970 – Galvanized steel (not Thyssen type) used in floor pan and wheel arches (Bob White in Pano V: 142); the “entire platform, including the floor, the longitudinal members, the wheel arches and the seat pans were galvanized.” (Boschen & Barth, p. 124)
1971 models – had galvanized steel in area particularly exposed to rust (Frere, p. 201)
1972-1973 – Thyssen steel use began (Bob White in Pano V: 142)
1973 – Thyssen steel: rocker panels, inner rocker panels, floor pans, & some other parts (Chuck Stoddard in Pano V: 142)
1975 – Thyssen steel: entire body treated (Bob White & Chuck Stoddard {began in Feb. ’75 production} in Pano V: 142, 192)
1976 models – had Thyssen steel in entire body except roof (Frere, p. 201)
1977 models – on – had Thyssen steel in entire body (Frere, p. 201); an “important step forward was the use of zinc-coated sheet steel for the manufacture of the entire body structure (except for the coupe’s roof on early production cars). Coated on both sides, this made the structure virtually immune against the formation of rust….” (Boschen & Barth, p. 143)


The Zinc steel added 22 lbs. to the weight of the body structure (Frere, p. 202)

Pano = Panorama volume: page number
Frere = Frere, Paul. 1997. PORSCHE 911 STORY. 6th ed., Patrick Stephens Ltd. Newbury Park, CA.
Boschen & Barth = Boschen, Lothar and Jurgen Barth. 1978. THE PORSCHE BOOK: A DEFINITIVE ILLUSTRATED HISTORY. Argo Books.


Note: the Panorama and Frere comments can be harmonized since most cars for one model year are constructed in the previous chronological year

[skrufy]

I have always heard for Dealer mechanic buddies of mine that 1974 was the first year. One of the Porsche engineering honchos had his personal 911 made without a lick of paint/sealants on it anywhere. He drove that 911 as his daily driver for a number of years. Another story they told me was that Porsche had a bare galvanized tub mounted on a pedestal on the waterfront in Hamburg or Bremerhaven to see how it would hold up in the moist salt water environment.....

Tim

[wayner]

Mine is a 73. Rust in the typical areas but surprisingly the floor is solid.
Here are some other solid areas that we found. The kidney and other lower bits sure look galvanized to me.

[mepstein]

They also made a couple tubs out of stainless steel.

[OsoMoore]

Originally Posted by Bill Verburg

Porsche built several unpainted '76 MY cars and had them on display at the factory from the summer of '75 at least through '80.

I'd love to learn more about these.

[FrenchToast]

Originally Posted by OsoMoore

I'd love to learn more about these.

Old thread.

But IIRC, at least one was displayed outside to demonstrate the 6-year (?) anti-corrosion warranty on the unibody at the time.

The one I remember was a Targa. It had nothing in it, except for suspension and steering so it could roll around. It was an unpainted shell.

Of course however, a large reason of how and why rust starts is the addition of all the production items. I.e. windshields, trim, etc. where dirt gathers, holds moisture, and wham.

And now in the new millennium, with poorer quality metal and paints and skimping on undercoating, I don't think rust prevention technology has progressed much.