Galvanized Fuel Tank

[wildthings]

In the states we can get muriatic acid at masonry supply outlets. It is used to clean lime/cement deposits off of stone.

You might be able to get Osphos of some other phosphoric acid product at a marine chandler.

[raygreenwood]

Muriatic or hydrochloric acid are very effective. In reality, you can use most any acid. You just want to be sure that the solution strength is not so high that you damage the metal. Sulfuric acid is dangerous because it does not readily mix easily. But it can be used.
Nitric acid will eat iron. But...nitric acid in concentrations above 18-22% will "passivate" by creating a flash oxidization layer that will no longer corrode...similar to what phosphoric acid does. Quite dangerous to handle. i do not suggest using nitric acid by any means.

that sodium bisulphate produc tshould work well. It is an "acid salt" it is made by a mixture of sodium hydroxide and sulphuric acid. I find it hard to believe that think that product is less of a poison than hydrochloric acid.
You should purchase a small amount, mix it properly following the directions...with water. Then place a small piece of rusted steel into it. It should slowly fizz. If not...carefully add some more of the powder until thesolution strength rises enough that the rust will fizz away within about 15 minutes or less. Always wear goggles and stay upwind. Keep water and a fire extinguisher handy.

Ospho is a mixture of phosphoric acid and dichromate. Most body shop supply houses should sell something similar. Its usually a liquid ..slightly greenish in color and and about the consistency of beer...just thicker than water. About $20 a gallon is all you should pay for it. Ray

[Lars S]

Just following up the copper pipe item:
is there any disadvantage (chemically or other) to use pure copper lines for petrol in a circulating set up as in D-jet?


/Lars

[412s2]

Thanks for the detailed information Ray, I’ll order up some swimming pool pH reducer (sodium bisulphate) and then practice on getting the concentration right! I’ll also have to get friendly with a bodyshop to find out what kind of phosphoric acid solution they use locally.

Regarding the use of copper in fuel pipes, as I wrote earlier I have read tales of copper causing oxidation of petrol, but not come across any reliable evidence; I am thinking it is an old wives tale. I have however found reliable report on sulphur compounds causing copper corrosion. It’s maybe not so much a problem nowadays with the use of ultra low sulphur fuels that a lot of modern cars need to run on.

Read this: http://www.med.govt.nz/templates/Multip ... P209_22744

http://www.gewater.com/industries/refin ... rosion.jsp

Hope this is of help Lars!

Neil

[Lars S]

Many thanks Neil!

This was most educational, maybe one should think twice befor using copper lines in a D-jet...

Thanks again!


/Lars S

[MGVWfan]

I'm wondering if one reason we don't use Cu for fuel lines over here in the Colonies much any more is the aggressive nature of our fuel. I've read that the new E10 blends that have been EPA-mandated most everywhere for 5-10 years are very bad at eating carb castings and brass fittings on classic musclecars (like 60's MoPars). I'm not sure what the mechanism is, maybe the hydrophillic nature of the 10% of the fuel that's now ethanol means lots of H2O in solution, plus the other oxgenates in the fuel just add to the problem. In any case, it's rare to see Cu lines on a car in any application in the US.

Personally, I use passivated (cad or whatever plated and painted) steel brake lines for fuel when I need a rigid line.

Now, along the same train of thought, to make things even more interesting, let's talk about fluoroelastomer lined (SAE 30R9/DIN 73379-3) fuel hoses and ACVW's or not...

[wildthings]

I have the fluoroelastomer lined hose on one of my engines. A slight bit harder to install as it is possible to mess the liner up when doing so, but otherwise it seems like the way to go.

[MGVWfan]

Me, too. Just replaced the lines in the engine bay after about 3-4 years, still pliable, but noticeably more rigid than new hoses, no leaks. Replaced due to having to "plumb-out" a leaky cold start valve (leaking fuel externally through the electrical connector). Much better than the lines in the '76 Duster I replaced recently, they were SAE 30R7, about 4 years old, and had started to crack when bent on the inside from reaction with the super-oxygenated fuel we get here. Replaced with 30R9 even though the Duster is carburated and doesn't need the extra burst strength. It's the crappy-fuel-resistance that 30R9 brings that's most needed.

Fuel tanks...I had a problem with my '67 MGB's tank and pinhole leaks a few years ago, fixed 'em and repainted, back to normal...but the MGB tank is not even terneplated (tinned) like most US fuel tanks, so leaks are expected (it's an MG for heaven's sake, not a VW! ). It does seem to work, even without terneplating, but I'd much rather have a tinned or passivated tank.

BTW, if you ever get a CSV leak and you live anywhere south of the Mason-Dixon Line, you can plumb around the CSV, the thermoswitch doesn't activate until around 32 deg F, and even then, it's not that big an aid to cold starting until you get down to ~20 deg F I understand. I'll see how it goes as we get colder here in Houston, and advise...

[Steve C]

Hi

Copper brake lines are not allowed to be fitted in Australia, I believe that this because the copper line will harden and fracture if it is allowed to vibrate.

Steve

[perrib]

You might try shcools and resorts that have pools. The phosphoric acid will work, it just takes longer. If you can keep the tank moving it helps. We would shake and rotate the tank every 1/2 hour. You can strain the acid to get the chunks out. Once the tank is clean it gets rinsed with hot water. I use a heat gun stuck in the sender hole to dry it fast. You might need two heat guns if it is cold. One in the tank and one to heat the outside. Environmentally plant based rust removers.
http://www.evapo-rust.com/ and www.ultraone.com