Steel Gas Tanks -What were they made of?

Stephen Hill · Nov 23, 2014

Does anybody know if the steel the Commando tanks were made from was plated, or was it raw steel? I am talking about on the fuel side of the steel.

Reason I ask is everybody tells me that after you clean out a rusty tank you have to line it to keep it from rusting.
I get the idea that if you use certain acids, such as muriatic acid, this would likely be necessary.
And PLEASE, let's not turn this into a discussion about the 9001 different ways of cleaning rust out of a tank.

So simple question, were the tanks made from a plated steel (such as tin) or some other rust resistant material? Or were they raw steel? Or?

Knowing that much will help me figure out what if anything I need to do around rust prevention after I remove the rust.

Stephen Hill

comnoz · Nov 23, 2014

Stephen Hill said:
Does anybody know if the steel the Commando tanks were made from was plated, or was it raw steel? I am talking about on the fuel side of the steel.

Reason I ask is everybody tells me that after you clean out a rusty tank you have to line it to keep it from rusting.
I get the idea that if you use certain acids, such as muriatic acid, this would likely be necessary.
And PLEASE, let's not turn this into a discussion about the 9001 different ways of cleaning rust out of a tank.

So simple question, were the tanks made from a plated steel (such as tin) or some other rust resistant material? Or were they raw steel? Or?

Knowing that much will help me figure out what if anything I need to do around rust prevention after I remove the rust.

Stephen Hill

No plating -raw steel

kommando · Nov 23, 2014

Phosphoric acid will etch steel and leave a thin rust resistant layer of Iron Phosphate which is ethanol resistant. Alternatively use non ethanol petrol and keep the tank full during storage, the ethanol takes up water in the fuel tanks at the petrol stations etc and then it pools in the bottom of your tank promoting rust.

Stephen Hill · Nov 23, 2014

Thanks for the info. Once I clean out the rust (using Molasses), I will keep it full of non ethanol gas. When I take it out of commission, I'll drain the tank and dump in engine oil, roll it around, and it should store okay until it gets used again.

Stephen Hill

comnoz · Nov 23, 2014

If you drain the fuel and hang a few bags of desiccant on a wire inside the cap the tank will stay shiny and dry in storage. Jim

madass140 · Nov 23, 2014

A little bit of track but
last week I had a tank which was fairly rusted inside, took it to my local electroplater and they removed all the rust
and zincplated the tank inside and out , the inside is now nice shiny zincplated. not sure how they removed the rust but no doubt was with chemicals. not sure how ethanol will affect the zinc plating.

concours · Nov 23, 2014

Stephen Hill said:
Does anybody know if the steel the Commando tanks were made from was plated, or was it raw steel? I am talking about on the fuel side of the steel.

Reason I ask is everybody tells me that after you clean out a rusty tank you have to line it to keep it from rusting.
I get the idea that if you use certain acids, such as muriatic acid, this would likely be necessary.
And PLEASE, let's not turn this into a discussion about the 9001 different ways of cleaning rust out of a tank.

So simple question, were the tanks made from a plated steel (such as tin) or some other rust resistant material? Or were they raw steel? Or?

Knowing that much will help me figure out what if anything I need to do around rust prevention after I remove the rust.

Stephen Hill

Someone ("everyone") told you wrong. All steel tanks even current production, are bare steel, needs no lining.

JimNH · Nov 23, 2014

kommando said:
Phosphoric acid will etch steel and leave a thin rust resistant layer of Iron Phosphate which is ethanol resistant. Alternatively use non ethanol petrol and keep the tank full during storage, the ethanol takes up water in the fuel tanks at the petrol stations etc and then it pools in the bottom of your tank promoting rust.

I have found it's the other way around. Gas with alcohol will keep the water in suspension unless, of course, it reaches saturation, then a phenomena know as phase separation occurs and an nonburnable alcohol/water layer fall to the bottom of the tank. This happens mostly with leaky caps allowing rain or seawater in boats but can happen on other vehicles.

Gas without alcohol will NOT mix with water and the water, being heavier, separates and pools at the lowest spot.

Before our gas was laced with alcohol it was common to add a can of "drygas" to our car's tanks in the winter to prevent the tiny water drops from freezing and blocking the fuel line. Drygas is nothing but alcohol and is no longer needed. The alcohol already in the gas combines with the water and keeps it in solution.

The bottom of my MG TF tank was completely rusted out from the water that collected there for most of 60 years. The car was parked long before alcohol was introduced. Your auto tank will now rust from the outside - in rather than inside - out. Of course most are plastic now.

Rohan · Nov 23, 2014

The lining referred to is Kreem, POR, etc. Tank lining kits....

Lotta folks use that to keep older tanks from rusting.
Tough finding one that does a good job though.

Back in the good old days (1920s) tanks were made from steel, plated with tin on the inside.
This was excellent at keeping rust at bay, but eventually the tin wore away.
Rather like cans plated with tin at the supermarket...

auldblue · Nov 23, 2014

I treated a metal tank with POR15 and at the time I read some poor reports about the coating coming of and blocking taps and filters but after 2 years it's still doing the job. But if the bikes not getting used I empty the tank.

J

kerinorton · Nov 23, 2014

I was told PA10 undercoat was very good for coating the inside of steel tanks. It is petrol resistant. Personally I keep my tanks full, so very little moisture laden air can enter the tank. I learned that as an apprentice mechanic. Generally we found in the industry, cars that were used all the time never god fuel problems due to tank corrosion. Another handy hint when handling petrol. If you have to use a plastic petrol container, fill it to overflowing and it will then never expand. Its the vapour pressure cause by fumes in the top that expands. No room for vapur, no expansion.
Yeah I know off topic.
All m/cycle petrol tanks I have seen are just ordinary steel. Empty tanks can corrode, whereas full tanks are always good.
Dereck

auldblue · Nov 23, 2014

In the winter we always kept the tractor fuel tanks full to prevent water in the diesel fuel but on a metal treated bike tank in a garage with ethanol petrol I'll keep it empty every time especially after a fuel leak on an old cafe bike. If the tank is treated it's not going to rust and you don't get the hassle of stale petrol.

J

concours · Nov 23, 2014

JimNH said:
kommando said:

Phosphoric acid will etch steel and leave a thin rust resistant layer of Iron Phosphate which is ethanol resistant. Alternatively use non ethanol petrol and keep the tank full during storage, the ethanol takes up water in the fuel tanks at the petrol stations etc and then it pools in the bottom of your tank promoting rust.

Click to expand...

I have found it's the other way around. Gas with alcohol will keep the water in suspension unless, of course, it reaches saturation, then a phenomena know as phase separation occurs and an nonburnable alcohol/water layer fall to the bottom of the tank. This happens mostly with leaky caps allowing rain or seawater in boats but can happen on other vehicles.

Gas without alcohol will NOT mix with water and the water, being heavier, separates and pools at the lowest spot.

Before our gas was laced with alcohol it was common to add a can of "drygas" to our car's tanks in the winter to prevent the tiny water drops from freezing and blocking the fuel line. Drygas is nothing but alcohol and is no longer needed. The alcohol already in the gas combines with the water and keeps it in solution.

The bottom of my MG TF tank was completely rusted out from the water that collected there for most of 60 years. The car was parked long before alcohol was introduced. Your auto tank will now rust from the outside - in rather than inside - out. Of course most are plastic now.

Word.

No more feeding Christy DryGas, the only benefit to corngas. I used it all year round on an occasional basis, kept the water at bay, no rusted-at-the bottom seam moto tanks :mrgreen:

JimNH · Nov 24, 2014

[/quote]

Word.

No more feeding Christy DryGas, the only benefit to corngas. I used it all year round on an occasional basis, kept the water at bay, no rusted-at-the bottom seam moto tanks :mrgreen:[/quote]

As a kid pumping gas we kept cases of Christy DryGas at the pumps in the winter; it was a high profit item that you could sell simply by asking. I think we got $1 a can at a time when gas was selling for about .28 and a can of Christy cost about .15 in bulk.

I agree, it's the ONLY benefit of corn gas. It cost more, and has less energy than straight gas, is a huge boondoggle of subsidies to make fuel out of food when there's real stuff to pump.

Sorry for the rant.

Steel Gas Tanks -What were they made of?

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