How to galvinize non galvinized body?

Hi all,
I'm beginning the strip down to bare metal of my '76 911. It was made in July of '75 so I believe it didn't come with the entire body galvinized(?). I will be sanding everything down because I have no experience with chemical strippers and do not want them to come back and haunt me after I get the car painted. Is there anything out there I can spray on to make it rustproof? I'm not too sure what galvinizing is exactly but I know it makes metal rust proof. I just need something (zinc spray?) that will help keep rust off that can be primered over(or a rust proofing primer that can be painted over). Please post all suggestions and comments. Thanks in advance!!

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Jeff
1976 911S

Jeff,
There are so-called "cold galvanizing" compounds available in spray cans. One I have on my shelf is made by Osborne. I wouldn't expect these to be anywhere near as good as hot-dipped (as in OE Porsche).
Also, check this:
http://www.por15.com/

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Doug
'81 SC Coupe (aka: "Blue Bomber")
Canada West Region PCA
members.home.net/zielke/911SC.htm

[This message has been edited by Doug Zielke (edited 05-15-2001).]

Jeff,

PPG DP-40/401 is a two-part epoxy-zinc chromate primer that is highly rated and praised by many Porsche restoration specialists. Very easy to use, no tricks or shortcomings that I know of ... I have been using it over 15 years, with great results.

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Warren Hall
1973 911S Targa

Thanks Doug and Warren. I'm looking for something that will last quite a while, so that cold-galvinizing in a can probably won't do, although I wouldn't need to buy a spray gun yet. I do have to use one for the PPG, right Warren? I'm assuming it's a great fighter against rust...how do I prep the bare metal surface for paint? Thanks!

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Jeff
1976 911S

Jeff,

The best treatments for bare metal are a class of treatments called 'conversion' chemicals that neutralize any rust and leave a surface coating of phosphate. 'Naval-Jelly' is one example, but messy to use. My favorite is a liquid called 'Oxy-Solve' that can be applied by brush, rag, etc.

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Warren Hall
1973 911S Targa

Warren,
I know I should probably just go buy it and read the instructions, but when you apply things like that, do you have to wipe 'em off, or do you just spray over when it's dry? Thanks!

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Jeff
1976 911S

Perhaps it's really more complicated than this, but I've always used that 'metal prep' stuff that is actually an acid of some kind. It etches the metal surface so it will grab paint well, and it kills rust. Apparently, there is rust on the metal you can't see. So you treat it with this stuff, wipe it off, and primer immediately.

But it's not a galvanized coating, which apparently is a very effective treatment. Didn't they start dipping shells at the factory in mid-'76?

Hey, I've got another question. When you strip paint from a galvanized shell, does it ruin the galvanized finish (galvanic, galvanostic, galvanizing, whatever)?

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'83 SC



[This message has been edited by Superman (edited 05-15-2001).]

Super,

You really must be bored, but your thinking is clear about metal prep ... phosphoric acid is usually one of the active ingredients (if not the primary or only active component) and a phosphate coating is the result, apparently black or dark gray in color!

And, your question about damage to the galvanized bodies is good, too! Sanding down to bare metal WILL INDEED SEVERELY DAMAGE OR DESTROY THE GALVANIZED SURFACE OF POST-'76 CARS! Welding on galvanized panels is also potentially toxic to the human doing the repair!

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Warren Hall
1973 911S Targa

Thanks, Warren. That's clear as a bell. Now one more. Can you strip a galvanized shell without disturbing the protective coating?

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'83 SC

Well, the only safe choices I know of are plastic-media blasting and chemical strippers, which only react with paints, not the metal underneath.

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Warren Hall
1973 911S Targa

Hehehe...apparently I've misspelled "galvanize". No wonder I couldn't find anything when I tried searching for it. Although mine is registered as a '76 (and I think my vin, 9116200291 proves it(?). It was made in July '75, so I'm assuming it wasn't entirely galvanized (dipped). For one, my roof is full of holes. I really want to get down to bare metal to make sure that each and every inch on this car would be free of rust. I bought the car (w/o PPI...stupid mistake) and discovered layers and layers of bondo. I'm just suspecting there may be more.

Warren..so you don't have to wipe it off? You let it stay on there so a phosphate coating is left, right? Thanks!

No wonder my auto shop teacher has always told us to grind or sand off the galvanizing before we weld. And I though it was only to make it easier to weld together!

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Jeff
1976 911S