Cleaning the tank

[979roadrunner]

Most of the people on this site have probably had to deal with rust in a fuel tank at some time, and there are various way of doing it, each with it's own adherents and advantages (and some with real or perceived drawbacks)

Muriatic Acid; This works well, but does have drawbacks. 1 It's dangerous to handle, you must wear rubber gloves while working with it. 2 It works almost too well, eating pot metal as well as rust. Since your average petcock is made of pot metal, you must fabricate some thing to seal the petcock hole with. 3 Environmental concerns. not quite as bad as it sounds, remember, they use this stuff in swimming pools, but it takes a lot of water to neutralize it, so you have to be carefull in it's disposal.

Evapo-rust; this is something I actually heard of from some members here.
works well, from what I've heard, and no one has mentioned anything about it eating petcocks, and it's environmentally friendly, but it's kind of expensive.

Electrolysis; I haven't tried this, but it sounds really cool, using water, baking soda, and electricity, couldn't be that expensive unless you don't have a battery charger, and no drawbacks I know of.

CLR; Should work, since the R is for rust, but I don't know what the drawbacks might be. I know you're not supposed to handle it bare handed, so not so safe, maybe, and it's not to be used on aluminum, making me suspicious what it'd do to pot metal. Supposedly pretty environmentally safe, according to the label.

I was reminded of an old forgotten technique the other day, though, while watching an automotive show on TV; Vinegar. That's right, regular old distilled white vinegar, that costs less than two dollars a gallon in my area, will clean rusty metal. Just pour it in full strength and let it work a few days or more, depending on how rusty the tank is. Cheap, environmentally friendly, uncomplicated. I don't think it'd even damage a petcock (someone correct me if I'm wrong about that)
Just thought I'd share.

[cowboyup3371]

I'm glad you posted this as I need to clean my tank out. How much vinegar do they recommend using? How would I line the tank afterwards or is it really necessary?

[kirkn]

Yep, my current favorite technique is vinegar. Works like a champ, just a little slow. And WAAYYY cheaper than POR-15 treatments.

Here's a link to a site dedicated to vintage Honda twins, where I detailed my own efforts using vinegar to clean my Honda CB200 tank. http://www.hondatwins.net/forum/view...hp?f=19&t=1376

Basically, I tried vinegar and it worked, but I didn't leave it long enough and I still had issues. Then I did the muriatic acid route, but I didn't know about the petcock, and in less than 10 minutes, the acid dissolved the petcock right out. So, finally I re-tried the vinegar and it ultimately got the tank pristine!

Use straight pure white distilled vinegar right off the grocery store's shelf. In my case, it took 2.5 gallons to fill the tank right up. There was so much rust & varnished old fuel that it took 2 flushings and re-fills over the course of a week.

When you're done, the wet tank will flash-rust RIGHT BEFORE YOUR EYES, so you need to rinse the vinegar or hose-water rinse off the tank innards IMMEDIATELY. I used about a quart of gasoline followed by compressed air blow-dry. Others use oil or alcohol.

I did this nearly a year ago now, and the tank is still perfect inside. No re-rusting or fouling at all.

Good luck with yours.

Kirk

[979roadrunner]

Thanks for posting, kirkn, it's good to hear first hand accounts. (Especially when I learn I'm not the only petcock melter out there )
If I do my tank again I'd either just keep it full afterward or use an epoxy sealer (not Kreem, I've had bad luck with it, and heard other's hard luck stories also) Alcohol rinses are a good thing.

[COGS]

I bought a CB1100F that had a very rusted tank...heard about vinegar, and gave it a try. Six gallons of distilled white vinegar and three days later I had a rust-free tank! Worst part was the vinegar smell in the garage!

[tas850g]

i use milk stone remover. Got it from Tractor supply company. No environmental issues i can recall and is no problem on paint. I use about a 4 parts milk stone to 1 water ratio.

I've posted how i use it last year.

Vinegar sounds interesting, i will try that on a very near future tank to be cleaned that is mildly rusted.

[tkent02]

I am thinking of combine two techniques, I like electolysis, but it's hard to get the rust from way back in the tank. Filling it halfway up and using different annodes that reach back there works, but it's a bit of a PITA. Vinegar or any acid makes the tank want to rust again immediately. Next time I might go with vinegar at first, then follow it up with electrolysis.

I wonder if getting the last of it with electrolysis will stop the flash rusting after from the vinegar/acid?

[Nessism]

I've done a lot of tank derusting and still haven't found a technique that's perfect. Evaporust may be the best but there will be dark spots in the metal where some of the rust is converted into some other compound. Phosphate solution gets the rust but leaves behind a chalky residue that must be scrubbed off the metal. Electrololyis works but as Tom states, it's hard to get back into all the corners. Oxylic acid works well and is cheap (deck cleaner), but again, it will leave a residue.

I've always followed up on the derusting with using a sealer, either POR-15 or Caswell's. By doing this you don't have to worry about the rust coming back - although application of the coating is not trivial in of itself.

[979roadrunner]

I'm glad everyone thought enough of this post to join in, I'm loving all the input, and getting more info myself.
The POR 15, you pour it in and move the tank periodically like the Kreem treatment? then pour the excess out? Same with Caswell's? wonder which is better?

[Nessism]

I'm glad everyone thought enough of this post to join in, I'm loving all the input, and getting more info myself.
The POR 15, you pour it in and move the tank periodically like the Kreem treatment? then pour the excess out? Same with Caswell's? wonder which is better?

I've used both and prefer POR unless the tank has structural rust, in which case the Caswell's will reinforce the tank better since it's thicker.

[Ponderosa]

Rusteco

Biodegradable, no gloves, use it over and over, then pour it on the garden. You can leave your fuel valve in, or take it out (advised), rinse out with water, dry with air.. Do not like liners they have a tendency to roll up and clog the works if not done right, not to mention screw up gauges..

http://www.rusteco.com/auto.htm

[979roadrunner]

Another interesting alternative

[tkent02]

Wow, $245 for a five gallon tank?
I'd rather spend $2 and do all the tanks I ever need to.
Electrolysis rocks.

[979roadrunner]

$245? Missed that. for the cost of a couple treatments, you could buy a tank.
Think I'll leave that one alone.

[Ponderosa]

No

Its $125 and you can use it forever if you can filter it out again. I run mine through a coffee filter and have used it four times.. It comes in a concentrate, you just add water.. $125 dollars is the price for a bottle with enough to treat a five gallon tank..