My '67 911S fuel tank: will boiling it ruin the pristine exterior tank finish?

[BottleNose]

I recently acquired a low mile survivor 1967 911S with original paint which has been stored for many years. The inside of the tank is varnished and has rust flakes everywhere. However, the outside of the tank looks like the day it came out of Stuttgart! Even the bottom of the tank is free from scrapes and road rash. This is the stuff of survivor concours dreams.

I want to take the tank to a shop to be boiled. Is this a harsh process that would cause the original finish to loosen and flake off? All other early 911 tanks I've seen have the original finish chipping off around the fuel sender and spare tire well. Seems to be a very delicate finish.

Is there any alternative to boiling a tank to remove the rust and varnish?

Thanks for any advice.

[davidppp]

I would do as little as possible to it.

The POR kit is good..I have used it and it works well..

Kind regards
David

[Cordts]

I just came out of a situation like this with a 67S and I can say that I have had many tanks boiled out over the years, I typically do repair on british cars and they have seen a lot of sitting around time and these associated problems with the gas tank. when they are "Boiled Out" as you say, the solution that they put the tank in will remove most of the finish,, but in your situation, you have few alternatives.. the last tank I did had over three inches of varnish in it and there was a lot of rust.. after being at the radiator shop for a couple of days, most of it came out,, for some of the surface rust that was in the tank, I put some phosphoric acid in it and let it sit for an hour and then rinsed it out. this acid treatment tends to leave any coating in the tank that has not been removed by the rust,, but the POR treatment is similar and is a sealer also.. so I suggest to do the boiling and then do the POR 15 treatment. since your tank is in such good external condition,, you will just have to do a little resto work on the exterior and then refinish it to have it back to like new condition.. anyway,, what is a great looking exterior if the inside is shot.. compromise, compromise,, good luck

[BottleNose]

Is this the POR kit you are referring to? Any other experiences with this product?



There is not much varnish in the tank, just rust, so I wonder if the phosphoric acid treament might work just fine, followed by a tank sealer.

>you will just have to do a little resto work on the exterior and then refinish it to have it back to like new condition

Yeah, but my car is supposed to be a survivor, and original finish is much preferred. I can't believe I'm concerned about the "patina" of my fuel tank, but I am!

[Cordts]

Did you ask the shop about just immersing the bottom half of the tank in the caustic solution,, I know you may want to keep that finish on the bottom,, but ometimes, you cant do what you really wnt to do..maybe they could do it without putting the whole tank in?? Secondly, try calling that 800 number on the POR site,, I would think they know the in's and out's of their product.. I have used many of their components and would recommend any of them, they are great.. I seem to remember a series of POR products that would give the result you are looking for..

They probably have a product that will address the varnish removal.. But,, Get ready for the additional problems that you are going to have,, stopped up fuel lines, cleaning and possible rejetting of the webers.. you are going to have additional problems beyond the fuel tank,, that are to be associated with the fuel tank / varnish problem