Evaporust is the only thing I use anymore. It's leaps and bounds better than anything else and takes almost no work.

 

I'd used evaporust with success. Bought a pretty rusted tank, a couple of applications and let it sit for a while (hours not day) and I put a short piece of chain in like an old school swing set chain and shook it around to help loosen the rest now it's just a little discolored.

 

We dont have evaporust or metal rescue where I live. But i've seen the WD40 brand rust remover thing similar but its kinda pricey about 20bucks a gallon

 

Well, that sucks Though per gallon I'm not sure $20 is that bad, evaporust is a little more . https://www.harborfreight.com/1-gallon-evapo-rust-rust-remover-96431.html. I got a quart, was plenty for a tank. Vineger should work ok but will take a much longer time. Either way, don't let it sit for too long and agitate it. After I did the EvapoRust, I hosed it out good with water, dried in the sun for a short time, then a bottle of rubbing alcohol. Picks up the water and dries fast. After some hours, maybe a day, sprayed a mist of WD-40 in there until I get to painting it. Regardless of the chemical, some make it easier but it's still a lot of work.

 

My bad not 20bucks a gallon i meant 20bucks a quart and i'd need about 4 gallons to completely fill the tank.I dont mind waiting. It'll take about a week before the other parts i need for my carb and other bits and bobs arrive. i just figured why not since i already have the tank off. After rinsing the vinegar out with baking soda and water and a final flush with water should I spray it with WD40? if i do how long will that keep rust out? Some people recommended kerosene and motor oil

 

I just looked up Evaporust on Amazon, that has doubled in the last few yrs, ouch! The nice thing about this product is that it is not a one use product. I have a 5 gal bucket of it over the yrs. I do a lot of older bike projects and it is all that I use.

In the past I have tried almost all the other methods, non work with the east and rust removal satisfaction that Evaporust does. I am sure there are others out there that do, I have just not found them.

Small linked chain is the way to go to help knock all the rust and old gas out of there as well. It is easy to get the chain back out with a small hook or a magnet to grab it and take it out all at once. Not putting a handful of bolts of what ever in your tank and then try to fish them out for hrs.

 

I just looked up Evaporust on Amazon, that has doubled in the last few yrs, ouch! The nice thing about this product is that it is not a one use product. I have a 5 gal bucket of it over the yrs. I do a lot of older bike projects and it is all that I use.

In the past I have tried almost all the other methods, non work with the east and rust removal satisfaction that Evaporust does. I am sure there are others out there that do, I have just not found them.

Small linked chain is the way to go to help knock all the rust and old gas out of there as well. It is easy to get the chain back out with a small hook or a magnet to grab it and take it out all at once. Not putting a handful of bolts of what ever in your tank and then try to fish them out for hrs.

I'll definitely try the chain. For evaporust I can't find any locally and amazon doesnt ship to my country. So my choices are electrolysis (i'd need to get a different battery charger), Vinegar, Muriatic acid ( which im hesitant to do), Or that WD40 evaporust like product.

With using something like evaporust could i get away with just justing 1 quart or maybe a gallon and just periodically agitating the tank and say do it over a 24H period?

 

Do not use hydrochloric acid.

 

I got 4 gallons of white vinegar they didnt have any distilled white vinegar nor apple cider. I cleaned out the tank with dish soap and water then stuck a chain and a quart of vinegar and sloshed it as best i could then filled to the brim i'll let it sit for a few days see how that goes. There was a lot of flaky rust when i rinsed it out and drained it. Im glad I got off my ass to clean this tank.

I was suspect when i cleaned the carb and there was a ton of rust dust in the bottom of the accelerator pump

 

You will need to flush out the fuel lines or replace them as well. Do a good check of the fuel system so all that hard work does not mess up the carbs.

Electrolysis method I have done once, when I first started older project bikes. Once you get the right charger, good solution and a jig for the type of tank you have can be done. What someone pointed out is that this method will make your tank structure weaker. It will removed metal from the inside of the tank. So I stay away from this method now.

 

Update: my seal broke and leaked the vinegar out i tried to neutralize it and flush it out as fast as i can but the chain inside got caught on this cross bar and caused it to flash rust. it looked pretty good for 8 hours.

Frustrating as it is i need to do the process again. Any tips to seal up the petcock i removed it because i know the vinegar would eat away at the petcock

 

Im wondering if i can just tape the hole and put the petcock over it with the petcock tubes out

 

I've thought up a solution to my sealing issue and will give the vinegar another go tomorrow. I cut a fuel hose inhalf, removed the two straws from the petcock and placed it over to form some kind of gasket. I hope it holds.

 

Vinegar won't hurt the petcock seals. Those things are made to handle much more volatile liquids like gasoline, ethanol and various oils. If you don't plan on filling the tank up with fuel right away then I'd recommend fogging it. WD40 works just fine. I personally use gun oil because I have gallons of it(my other hobby).

 

I've heard vinegar eating away at the petcock from other threads since is aluminum/pot metal. Im going to use the petcock but seal off the hole with some gasket im fairly confident that should hold long enough. For fogging i originally planned WD40 or 2T oil mixed with gas

 

Update: I soaked the tank in vinegar for 3 days came out perfect but as i was trying to flush out the sludge and flakes from the bottom it flashed pretty bad. After Vinegar i neutralized it with about 2 boxes of baking soda and 3gal of water sloshed that all around till my arms started cramping. Drained that out flushed with distilled water until it ran clear then i fogged with WD40. I figured trying to get the pesky chunks from the bottom would take time so i fogged it. After getting the flakes out it flashed pretty bad.

Im thinking of trying electrolysis since its just very light surface rust and most of the flakey and chunky rust is out of the tank.

 

This was after flushing with water you can see it got pretty yellow. After fogging with WD40 and maybe 15mins all that yellow has turned into a brownish/reddish surface rust.

 

It will be interesting to see how much time it takes you to get the tank how you want it using this method.

 

I'm guessing another 2 days since its not super heavy rust mostly surface rust. and since theres no acid involved probably wont flash as fast as the vinegar.

 

I dont know what im missing here and why its flashing so fast? is it the humidity? even if i could seal it with POR15 or Kreem it would have flashed before it was dry enough to pour the tank liner.

 

Update: I proceeded with the electrolysis! Amazing result I only left it for about 8 hours. when I went to go check on the sacrificial rod i dumped the fluid. Lo and behold rust free. I flushed it wiht a couple rionses of water followed by denatured alcohol when i couldnt get any more water out. flushed the alcohol then rinsed with gas then fogged with 50/50 Gas and 2T oil. I'll check on it in the morning see if it flashes im pretty sure it wont.