Cider vinegar

[BooG]

Is it true that if I fill up the gas tank with cider vinegar it will get rid of rust?
Obviously I would remove the tank and the old gas before hand.

[Bob_Roller]

You can use regular distilled vinegar to remove the rust if it is less costly than cider vinegar, I did it on one R65 and a Guzzi fuel tank that were severely rusted .

It will probably take 2-3 weeks to get the rust out .

You need to turn the tank over to get the top of the tank of the tank cleaned .

You need to remove the fuel tap and put a rubber stopper in it's place, the vinegar will erode the metal if you don't .

I found a large rubber stopper to use in place of the fuel cap .

Got it at a beer and wine making supply store .

[BooG]

Fantastic! My next job!
Thanks for that!

[marcmax]

I cleaned my tank before relining it with a mix of white vinegar and salt. It forms a weak sodium acetate and hydrochloric acid solution and cleaned the rust and old bits of tank liner in 2-3 days. Be sure to rinse well with a baking soda solution with any acid cleaner to neutralize the acid. Rinse well again with water, then alcohol to remove any moisture left and get a liner in asap. The bare tank will flash rust in minutes.

[Bob_Roller]

Don't know, if you plan on relining the interior of the fuel tank after removing the rust .

No idea what is available in your area for liner, but the one I've been told to stay away from, is Kreem .

Caswell has a product and it seems to be the choice of a lot of people, I used POR liner on both tanks, so far no issues, 5 years on the R65 and  2 years on the Guzzi .

[marcmax]

The Caswell tank liner is an extremely durable epoxy tank liner, works really well and is now available in a red color that replicates the factory tank liner (in case you are going for a concourse restoration).

[Tony Smith]

What they all said above - I am no tinto waiting and if you alreayd know you are going to be putting a liner solution in - remove the fuel tap and put a rubber, cork or whatever bung in, make a timber bung for the filler but do not put in it just yet.
 
Go to nearest pool supply place and buy 5lt of swimming pool acid. Pour in as much acid as you feel like wasting and stand well back.
 
HCL eats oxides of steel and iron, but leaves actual metal untouched. once the reaction subsides, pu tin filler bung and roll upside down, removing the tap bung as you go.
  
When reaction subsided, rinse well with carbonate solution (or if you have unmetered water, put fuel tap bung back in and leave tank in back yard with water running through it for a few hours.
 
Apply liner solution....
 

BTW. capture the acid as it comes out of the tank and through all your spanners, sockets etc into it. When they are clean, toss the contents of your "hope chest" bottle/bucket/whatever that is full of all your spare nuts/bolts and Screws and give them a rinse too.
 
Tools/nuts/bolts etc need to be well rinsed and then quickly dried and sprayed with CRC/WD-40 etc to prevent rust re-appearing.

Wear gloves and a mechanic's vest/apron if you have one - Muratic acid really does a number of man made fibres in clothing.

[Tony Smith]

Should have also mentioned - a good way to dry a tank out prior to putting the liner epoxy in is to use a vacuum cleaner that has the ability to also be a blower, and let it blow through the tank for a few hours (and if you can put the tank in the sun, so much the better) - move the hose around frequently to ensure that the stream of air gets to all places int he tank.
 
some people pre-rinse the tank with Methylated spirits before doing the last step on the basis that metho and water are miscible and the mixture has a much lower surface tension and will evaporate faster. I've never bothered as if you think about it, even a domestic vacuum in "blower" mode pushes an enormous volume of air through the tank.

[balibeemer]

A 10% Phosphoric acid solution will remove rust overnight. don't forget to neutralise the surface afterwards with a baking soda solution. Keep Phosphoric acid away from aluminium ( oops - Aluminum)

[Tony Smith]

Keep Phosphoric acid away from aluminium ( oops - Aluminum)

Why? Phosphoric acid is a major component of a significant number of aluminium cleaners. It does of course have the disadvantage that it leaves a deep grey and pretty lifeless finish in its wake (you need hydroflouric acid to restore a bright shiny surface) but as far as I know, it does not harm alloy overly much.

[Luca]

I dislike the factory red lining because it's hard to differentiate from rust.  Linings of a different color will make differentiating easier, which could save some major headaches in the long run.

[balibeemer]

Tony - only speaking from experience. I though phosphoric acid would be good to clean some Al speaker mounts. Put them in a 10% solution and the next day, there they were - gone!
Mind you, it could have been the mice!

Maybe 10% is too aggressive? - I just don't know

[Bob_Roller]

Next time you have a can or bottle of your favorite carbonated soft drink in hand, check the contents, chances are good, that it contains phosphoric acid as well !!!!!

[Tony Smith]

Tony - only speaking from experience. I though phosphoric acid would be good to clean some Al speaker mounts. Put them in a 10% solution and the next day, there they were - gone!
Mind you, it could have been the mice!

Maybe 10% is too aggressive? - I just don't know

I must admit i don't know the strength - whatever comes in commercial alloy cleaner I guess - as my 2lt of the stuff was siphoned off from a bulk storage I've no idea.

[BooG]

I think I'm gonna go with the vinegar and salt idea. 2-3 days sounds good..don't really want to be hanging around for weeks, and I don't want anything to aggressive either!
How much to put in; in terms of litres of vinegar and amount of salt?