Cleaning gas tank

[vern hodgson]

This is my home made system for cleaning the crud from a gas tank. In process not done yet.

[midgetracer]

That is quite a setup. Personally I would use chemicals such as toilet bowel cleaner and then rinse it dry it with acetone and line it with a good liner. I know this statement will not go well with some , but it has worked for me for many years.

[Gary WA]

Gas Tank Tumbler! Are you going to sell the rights?

[BRENT in 10-uh-C]

Originally Posted by vern hodgson

This is my home made system for cleaning the crud from a gas tank. In process not done yet.

Looks ingenious Vern!! Always kinda curious to hear how folks plan to get the media behind the baffles, ...and then clean the backside of the baffles??




















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[California Travieso]

Vern,

You should have just put it in the cement mixer behind your contraption!

David Serrano

[ronn]

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I bought a HF cement mixer 4 years ago, to use as a tumbler...........

still sitting in the garage unassembled!

[California Travieso]

Originally Posted by ronn

I bought a HF cement mixer 4 years ago, to use as a tumbler...........

still sitting in the garage unassembled!

I hear you. Sounds like my garage. I have a HF engine hoist I bought a year ago that is still unassembled.

David Serrano

[fundytides]

Brent. Love the pictures of the gas tank with the top off. I have a 31 tank that I decided not to use because it has rotted baffles and a lot of crud in the tank, so I cleaned and sealed another pretty decent tank. I thought I would experiment with the bad one. When you cut the top out, do you leave the welded/crimped area in place and cut inside that area? If so how far in to be safe? If this is the way you do it, do you then just weld the cover back in place.

[30 Closed Cab PU]

Originally Posted by BRENT in 10-uh-C

Looks ingenious Vern!! Always kinda curious to hear how folks plan to get the media behind the baffles, ...and then clean the backside of the baffles??




















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Thanks for the Pics Brent. Have heard of these mysterious baffles in previous posts. Often wondered what they looked like. Looks like my plans to use a borescope through the Fuel Shutoff to inspect still would not get into the the baffled areas, only into the center part of the tank.


Seems the only good home method is a liquid such as Vinegar/Evapo Rust/Rust 911 which fills the tank?

[BRENT in 10-uh-C]

Originally Posted by 30 Closed Cab PU

Seems the only good home method is a liquid such as Vinegar/Evapo Rust/Rust 911 which fills the tank?

Well, I don't know what to say whether that is a good "home method" or not, so allow me to pose some questions for you to think about that might help you in your thought process;


Starting at the beginning, the sheetmetal used to manufacture the Model-A tank was originally coated with a thin layer of Terne. Once the metal was stamped, the tank halves were fuse-welded, and the tank was protected from rust. Over time while driving, fuel sloshing inside tends to rub away at the Terne protective coating exposing bare metal. That bare metal begins to form rust which when more fuel is sloshed against it, it created sediment. After awhile the iron oxide spreads to adjoining areas creating the rust issue that many experience inside the tank.


Next, we all know that many tanks that have been taken to radiator shops to be "boiled out" in sodium hydroxide & water, and this is often touted as a solution to the rust problem. What most never consider is that when you search the effects of the acid on the Terne finish, you realize that it dissolves the coating, ...again leaving more uncoated metal. FWIW, any of these degreasing acids are great for dissolving organic matter but do not have any effect on rust. So before we had a tank that had several rusted areas due to bare metal, but now we have lots of exposed areas that over time will start to develop rust. If you can get all of the insides cleaned and coated immediately, you have a solution to your problem as long as the rust sediment is not loose on the inside walls which can cause a problem with sealer adhesion.


So now we get to the last couple of thoughts. What we have found is the bacterial rust converters do a great job of loosening the iron oxide but do nothing for the remaining coating such as the Terne finish. Often times, the rust forms under the coating, so you still have the rust but it is under the coating and still growing. Next, which I feel is one of the biggest issues plaguing the home restorer is getting the tank thoroughly sealed. I could post picture after picture of tanks that we have opened to find bare metal that the sealer never covered. So all they did was spend a lot of time and effort but never cured the problem, so the rust continued to grow.


IMHO, the ONLY way you can correct the problem is to soak the tank is caustic to rid all of the coatings. Then cut the tank open to fully expose the tank and baffles (-not just cut small holes and try to media blast thru the holes) so that it can be thoroughly media blasted where all of the rust can be eliminated. Then the metal needs to be treated with Phosphoric acid to clean the pores and then neutralized. Once the tank has been cleaned, reassembled and pressure tested, it must be filled with sealer. From my experiences, there is just no way that 1 quart of sealer can totally reach all of the surface area of the tank's insides. It takes a minimum of 4 gallons, and preferably 5 gallons of sealer inside a 11 gallon Model-A tank to ensure there is enough volume of sealer to completely coat everything including baffles. Now when you factor in that most good quality sealers are around $120.00 a gallon plus tax/freight, and you are going to drain all but about 1 quart out of the tank, it kinda seems like a waste unless you are sealing several tanks as the shelf life on an opened can of sealer is not too great. So while these experiences above are lengthy, I trust you now understand why I am unsure there is a good home method on restoring tanks however I am always open to suggestions.


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[30 Closed Cab PU]

Thanks for taking the time to provide a detailed answer. Much Appreciated.
Have seen snippets of info here and there, some in your responses, this pulls your thoughts and processes neatly together in one place.

[Bob from Northport]

I just picked up a tank from Brent's shop for a customer. All clean and ready for paint. Really great job!!! Thanks again!!!

[fundytides]

Brent. I understand completely. I just finished "cleaning and sealing" the tank that I chose as an alternate to the one with the rotted baffles. I followed the directions on the etch liquid and the sealer and in my opinion, probably obtained 50% or less results. That's why I am thinking of cutting open my original tank to clean it and repair the baffles. I am in Canada so it would not be practical to ship it to your shop for the proper repair especially with the border crossing issues for steel now. Just thought I would have the "fun" of trying it myself. Thanks for your detailed explanation.

[vern hodgson]

Originally Posted by California Travieso

Vern,

You should have just put it in the cement mixer behind your contraption!

David Serrano

I tried, wouldn’t fit, so the mixer drives the set up.

[midgetracer]

Brent, could you please identify the sealers that you feel are professional grade and worth using to seal a tank?

[fordcragar]

This is a very informative thread on tanks. I'd like to know a name of a good sealer as well.

[my4dv8]

I realise this wont show folk how to clean a gas tank or how not to as I do not know what process was used here on an under seat 32 pickup tank. But rest assured it was a very rusty disaster , and obviously all the sealer went to one end. I presume it was etched or some such as I am confident that it has never see fuel since the attempt, man was it full of flakey rust.. We obviously cut the top out and started to clean the rust and remove the baffles for under seat storage.