GAS TANK un SEALER

[mAVERICK]

2 OF MY MODEL A'S WERE SEALED WITH TANK SEALER BACK IN THE 80'S. MOW WITH NEW GAS THIS IS A PROBLEM. I FOUND AIRCRAFT STRIPPER TO BE VERY EFFECTIVE. I GO TO BUY IT AND THEY HAVE CHANGED THE FORMULA AND IT IS NO LONGER EFFECTIVE. THE EPS HAS SHUT DOWN ALL OF THE REDI STRIPS. CAN ANYONE HELP?

 

[Sunnybrook Farm]

I have the same problem with one that I sealed in the late 70s, it is putting a goo through the system that I can hardly wash off of my hands. I am going to dip the zenith in berrymans to try and get it working, it was so fouled that the throttle was locked shut. I am thinking of putting some E85 in the tank to try and clean it out since ethanol seems to dissolve the stuff. Then recoating with a modern sealer. Don't really know what to do with this mess.

 

[Gary WA]

My take is no sealer-Just clean clean clean!

 

[ronn]

never ever had a problem with Hirsch sealer. never...........


get another tank and start over.

 

[noboD]

Try the molasses trick.

 

[rotorwrench]

Methylene Chloride is still available but it is getting harder to source every year.

 

[whirnot]

I used acetone. Nasty stuff, and not cheap, but it took the sealer out. And ate the paint......

 

[37 Cab]

With the acetone in it add a couple handfuls of sheetrock screws and shake, shake, shake… Tumble and shake. Repeat.

 

[whirnot]

With the acetone in it add a couple handfuls of sheetrock screws and shake, shake, shake… Tumble and shake. Repeat.

I would be a little afraid of sheetrock nails getting stuck in the baffles, but steel shot might work.

 

[Bob Bidonde]

I downloaded these gas tank cutaway pictures from the internet. I do not know who these tanks belong to, but the pictures are very informative of the gas tank innards.

 

[Joe K]

You might try setting up an electrolytic bath using the INSIDE of the gas tank. The tank is the part to be cleaned, and the other electrode could be put in through the gas fill.

MANY instructions on electrolytic rust (and paint) removal are seen on the Internet. One smaller version can be seen at https://www.wwgoa.com/article/removing-rust-with-electrolysis/#

Most users of this method recommend using washing soda, which is around but not too widely. Around here (New Hampshire) we don't seem to have it (it may have something to do with our hard water) so I have substituted LYE (Sodium hydroxide) in low concentration. All you need for the bath is an electrolyte bath of the "basic" chemical variety and for me lye fits the bill - and you don't use much so its cheap.

Some have decried the lye, but I have found in the low solution concentration like for the bath, you can immerse your unprotected hands - they come out "sparkly clean." But it is apparent the bath is very "drying" to one's skin. Nothing a bit of lotion before bed can't solve.

The nice aspect of lye for me is it will remove paint under the action of the bath and for you I expect it will remove the gas tank coating.

Plus doing this electrolytically you will prepare the inside of the tank with a perfect rust-free surface for re-lining with the Hirsch product mentioned.

Keep in mind though that electrolytic rust removal does remove the rust. Maybe TOO well. After conversion of the rust you leave a metal surface which is "ready & willing" and all set to go to take on atmospheric oxygen. Like prepared to take on oxygen on a "molecular" level?

My experience with electrolytic bath is that basically in the time necessary to rinse off the bath, the "rust bloom" has started again. So I usually either blast the surface (to create adhesion points for a coating) or use a Phosphate etch, which can be found for cheap in Kleen-Strip "Prep & Etch" which is found at the big-box stores.

Given a sequencing, I might do the electrolytics, then carefully flush out the tank to remove electrolyte and removed material, then put in a cupful of small square nuts in the 1/4 or 3/8 bolt size, then add on top "Prep & Etch" and shake, shake, shake. Then rinse with water and get all the nuts out. Somehow.

Hope this helps. I have had good luck with the square nuts and paint remover, but as you say, your EPA knows what is best for the environment. I have not tried electrolytic in a closed container as I describe.

Joe K

 

[Keith True]

I haven't heard of lye being used for anything in a long time.In the late 50's when I was little my dad bossed a good sized painting outfit in Exeter N.H.On Fridays all the paint pots,metal stir sticks,hooks,some of the brushes,and drill operated mixers would go in the lye barrel.On Monday morning all the stuff looked like new.There was no latex paint,no plastic or paper pots,no wooden stirring sticks,no sprayers and no aluminum ladders.I'll bet lye would strip the sealer out of a tank.

 

[54vicky]

I would think if the alcohol gas is causing it to release.why not just use ethanol.if the new gas is the cause just fill half way let it sit then agitate if that works drain into container take to recycle place.come back fill to top repeat agitating.this should work IF the new gas is at fault.I suggest the half full so it can soak in same applies to the full remark.

 

[BRENT in 10-uh-C]

I downloaded these gas tank cutaway pictures from the internet. I do not know who these tanks belong to, but the pictures are very informative of the gas tank innards.

Bob, the two outside pictures posted above are pictures I took if customer's tanks that we have restored.

I haven't heard of lye being used for anything in a long time. I'll bet lye would strip the sealer out of a tank.

It has been our experience that the only thing that will soften (-NOT totally dissolve or strip) tank sealers is Sodium Hydroxide in about a 15-18% solution mixed with water that has been heated to around 200°. Generally soaking the tank for 24-36 hours will allow it to soften the sealer enough where it can be scraped away followed by mediablasting the remaining traces. It is worth noting that this high of a concentration of acid will dissolve soft metals such as solder. Old radiator shops did not use that high of concentration in their cleaning tanks (-general less than 10%) simply because it would dissolve the solder around the tubes to the headers. Unfortunately 10% is not strong enough to soften most sealers.

I also have a theory based on what we have found that it really is not the sealer itself that is affected by the modern fuels. What causes the adhesion problems is where the metal surface was not properly cleaned prior to the new sealer being added. It tends to flake away when the metal under the sealer continues to rust. A great example is the pictures below that show the sealer was applied however the metal was never totally cleaned. Even when organic rust dissolvers are used, it leaves a residue that the tank sealers will not adhere to very well.


.

 

[gdmn852]

Interesting reading I will have to clean my tank and perhaps seal it .Thinking of getting rustX that dilutes with water and just fill it up and shake it up,and if it leaks then seal it. I don’t think this tank has been sealed before.Hopefully the newer sealers are more resistant to ethanol fuel.that wasn’t a issue years ago .

 

[Rich in Tucson]

Just a clarification from an old biochemist messing with metals in and on old Fords et al.: Sodium (or Potassium) Hydroxide solutions (lyes) are strong alkalis (not acids) and given enough time and at particularly elevated temperatures will attack and dissolve Tin, Aluminum, Zinc and Cadmium, Chromium, and Copper. But not iron or steel, and therefore they are great cleaning agents for most metals (Oil Eater is a great carbon remover for pistons and valves IF used judiciously; it will remove carbon at a far greater rate than it will remove Aluminum from pistons for example).

If I had a flaking old tank sealer on a degraded gas tank and could not afford to cut it open for restoration I would not hesitate to clean it with lye (or similar alkalis) with frequent monitoring to determine its effectiveness despite knowing that I am slowly removing any (if any) residual original Terne plating. Then a "modern" sealer could be used if trusted (I frankly don't know) or scrupulously avoiding any addition of moisture in the gas tank with perhaps the addition of a top end oil to the fuel might prolong the further rusting of exposed steel in the tank.

 

[Sunnybrook Farm]

My tank isn't peeling, the sealer is dissolving and getting into the fuel. Part of the problem is that I didn't have much fuel in the tank and didn't drive it very much so I think I am getting a concentration of the goo. I may need to do a temporary set up that is on the Ford Garage that originally came from the Ford Barn: http://www.fordgarage.com/pages/kellyshutoff.htm
The sealer feels kind of like a rubbery coating that never got hard. It worked great for years but things change. Putting a lot more fuel in the tank may help or at least E85 then drain it out. Starting to make a rear mounted fuel cell look good.

 

[1crosscut]

If you can get some of the goo out of the tank see if it dissolves in carburetor cleaner. If it does (I'm thinking it very well could) buy a gallon and slosh it around for a while.

 

[BRENT in 10-uh-C]

Just a clarification from an old biochemist messing with metals in and on old Fords et al.: Sodium (or Potassium) Hydroxide solutions (lyes) are strong alkalis (not acids) and given enough time and at particularly elevated temperatures will attack and dissolve Tin, Aluminum, Zinc and Cadmium, Chromium, and Copper. But not iron or steel, and therefore they are great cleaning agents for most metals (Oil Eater is a great carbon remover for pistons and valves IF used judiciously; it will remove carbon at a far greater rate than it will remove Aluminum from pistons for example).

If I had a flaking old tank sealer on a degraded gas tank and could not afford to cut it open for restoration I would not hesitate to clean it with lye (or similar alkalis) with frequent monitoring to determine its effectiveness despite knowing that I am slowly removing any (if any) residual original Terne plating. Then a "modern" sealer could be used if trusted (I frankly don't know) or scrupulously avoiding any addition of moisture in the gas tank with perhaps the addition of a top end oil to the fuel might prolong the further rusting of exposed steel in the tank.

You are correct on both comment Rich, the Sodium Hydroxide is a base however when it is shipped, evidently the government and the shipping companies don't realize this as they require it to be labeled as an acid and I must pay the hazardous fee associated with the freight charge.

The other thing we find is that the Terne coating inside the tank does indeed get dissolved when using the Sodium Hydroxide. The one thing that we both need to mention is that anyone that does use the Sodium Hydroxide for cleaning needs to use EXTREME caution when using this stuff. Even when it is room temperature, I know from personal experience that a 15% solution of NaOH will burn your skin. When that concentration is heated, it becomes even more dangerous. Splash it in your eye and it will likely damage your eye. Get it on your skin and, ...well you know.

 

[whirnot]

If you can get some of the goo out of the tank see if it dissolves in carburetor cleaner. If it does (I'm thinking it very well could) buy a gallon and slosh it around for a while.

That's what I did, to find out acetone ate it right up.