68 GTO Gas Tank Finish
 

Hey Everyone,

I have two gas tanks for a 68 GTO. The one from my car and one that I purchase in a big parts purchase. Both tanks have a coating on the tank. Some sort of undercoating. Is how I am supposed to leave the tank look or should it be raw metal?

Thanks In Advance!

Galvanized

I used spray clear gloss on my new Canadian tank from PY circa 2005: gloss holding up nicely. Recall wiping down with paint thinner before spraying.

Yes - the original factory tanks were left bare "raw" metal. The tanks were made with a special coating that resisted corrosion and that's what gave them the galvanized type look (the steel manufacturers called this "terne" steel...some type of lead/tin coating).

If the car was dealer undercoated the undersides of the tanks were typically sprayed with the same undercoat.

As already mentioned....you can leave them bare or coat the thoroughly cleaned new tank with some sort of clearcoat. The new tanks (like those made in Canada by Spectra Premium) typically have an oily coating on them from the manufacturing process so make sure to get all that off if you're going to clearcoat the tank.

the only way to go nowadays is with the recently available stainless
steel repro tanks.....they have a beautiful show stopping finish that will never tarnish,
and best of all they are very inexpensive and ethanol fuel does nothing to the inside of them.
It's a no brainer. You can also order stainless steel straps to go with them. I've got these
tanks on all my A-bodies. Sending units are also available in stainless steel. You can order them from Auto City Classic.

I went with the Canadian manufactured tank as well. Ordered at my local parts store. Wiped down with degreaser and clearcoated. Holding up well so far. Hadn't heard anything about the recently available stainless...sounds like a good alternative.
Black or undercoated tank is a no-no in my book.

I painted my new spectra tank with Krylon Dual satin black...I didn't want it to distract from my new Strange Dana 60. lol Didn't wipe it down or nutin'. Looks good for now but time will tell...

I put absulotly nothing on my GTO's new tank, and after one winter it was begining to look "Milky White". You gotta put some kind of coating on it most definetly.

P Glade nailed it: original tanks were "terne plate", not a common process anymore due to EPA regs. The tank i bought from Auto City Classic was cleaned, then BC/CC with a silver color. Not exactly original, but holding up well.

The new Spectra brand tanks use a coating like this but I think it's been "toned down" a bit by subsituting zinc, or some other metal, for the lead that used to be used.

That's likely what caused the "whitish" look with time mentioned by a poster above...zinc, being a "sacrificial" coating, tends to sometimes dull out or take on this chalky look. Probably moreso in humid environments. It's the zinc doing its job. Unfortunately, looking good for a long time isn't in the marching orders handed to zinc!

the clear coat won't distract from the Strange Dana60. Pretty sure.


The original factory straps have a metal grain finish that looks like damascus steel. again clear coat brings decent factory straps to excellence.

Were the original factory straps black in color?

some were black, some were natural.

the straps were originally galvanized steel...at least the many bare ones I've pulled and seen on cars with unpainted straps.

The original tanks were made with continuous sheet galvanized steel from the mill itself (which is why the edges and welded areas were bare steel as the tanks were cut, formed and welded after galvanizing). The galvanized coating was very thin and was primarily zinc but with lead and tin additions to increase "bend-ability".

The white discoloration could occur on these tanks in the day but the coating will stabilize to a dull silver-grey over time when exposed to wet and dry. The tanks done today won't have lead which will make the coating initially more silver less grey, will increase the whitish powder initially but with time the two will look very similar. Like anything repro I assume the coating is much thinner than original.

I am in the galvanizing business, for 30 years, so this is an area I know well.

The coating on the tanks is the same you see on corrugated roofing like on barns and prefab buildings etc.

John,

Thank you for the response. What process would I use to make this tank look as close to original as possible?

depends on what you want; for a brand new look I'd clear it like others mentioned but if you want a more natural look you could try rubbing it down with a very light oil (rubbing but not leaving heavy oil residue, this will prevent or remove the white stuff and over time will darken the coating so that the tank will look more "right" on an older resto or unrestored car

Anyone ever try to zinc "brush plate" a fuel tank? Seems like it should technically be possible.
JohnnyB