Depends on how bad it is. If it has crud plus a lot of rust: I put a couple of handfuls of nuts and bolts in, some dishwashing liquid and water, seal the tank then mount it on an old barbecue motor and rod. Change the position every so often and let it run - bare metal on a bad tank can take several hours. Then I use the complete POR 15 system to clean and coat it.
If it just has surface rust and you didn't leave gas in it for 26 years, just use the POR 15 process.
Alan Cleared m out....left only 59 BSA Bantam (Trials) 78 Triumph Bonny (UPS) 02 Suzuki GS500
I agree with Alan, except I don't have a BBQ, so I do the same thing, then wrap the tank in a huge quilt or multiple blankets and put it in the dryer with the heat turned off when the wife is not home!!! If you put enought blankets on the tank won't roll around and get dented, but with that I can leave it for an hour... that will do the trick and if you have a lot of rust, it will completly take it out and show you the holes!!!@
I had a tank with lots of rust and when I cleaned the inside like others have described. After that i sandlbasted the outside rusty areas and the holes popped thru. I repaired the biggest holes with epoxy, the smaller holes with lead solder, and sealed the tank on the inside with a tank sealer product by "Hirsch" (I think i spelled it right). I used three thin coats and it worked great. A half pint can is more than enough for a motorcycle tank. They have an 800 number and you can have it in a couple of days. If you can't locate them, e-mail me, I have the can out in the shop.
The last rusty tank was cleaned using a large amount of old hardware I had on hand. I shook the tank vigorously and got a good workout. Later I noticed a small pimple on the front of the tank. Oh no! Some of the hardware was too heavy and dented the tank from the inside. :^(
My tank had a bit of rust but I just left it and nothing happened. The best thing to use are the citric acid based rust removers as they don't harm the solid metal. You can buy it or send it off for treatment. Have a look on the internet.
My son's tank seemed to be loaded with rust, but most of the brown stuff turned out to be evaporated fuel which broke loose and started circulating to the carb after loosening in fresh fuel for 30 days or so. It was a mess.
I highly suggest Caswell epoxy tank sealer when you finish your various tank treatments, what ever you decide upon. You can find their link in our useful links section....
I know my method sounds very catastophic and very well may be but ill post as i have a thick ebnough skull for the flamejob!!! I had a tank with tons of rust in it and couldnt do much to get it out. I tried bolta n stuff inside but kept fitting it then seeing rust clog up my 2 dollar inline filters. Really bugged me for a bit until i looked around the garage for something drastic... I had a pool at the time and had some chemicals laying around. I took a gollon of muriatic acid and poured a little in the tank. Immediately the acid ate through the pot metal petcock so i was pretty devastated thinking oh crap there goes the tank!!! But upon further inspection the acid ate away the rust and left bare metal unaffected!! I am no scientist or whatever but i still have the tank now and its characteristics havent changed enough to leak or anything and its been years (knock on wood)!!! If i had to do it again i would probably take the petcock off heheh but for me it was a 30 min NO DENT fix to take ALL the rust out!
That stuff poured out like butter.
Of course i discarded the contents in a safe manner complying with all environmental standards...
I dont know if its suggested fix but interesting reading i suppose Try it on an old dirtbike tank you dont like. So many metals out there i dont know what holds up and what dont. I also know i didnt leave it in for long. I cleaned her out REAL GOOD afterwards too.
You're absolutely right on about the muriatic acid. I've never used it, but know someone who did with excellent results. It's just that I can't remember the amount that he used or the time period & if he used a neutralizer afterwards or not. But absolutely, it's extremely effective, just have to keep an eye on it so it doesn't work TOO well, LOL!
Originally posted by freakinhungover: I took a gallon of muriatic acid and poured a little in the tank. Upon further inspection the acid ate away the rust and left bare metal unaffected!! I am no scientist or whatever but i still have the tank now and its characteristics havent changed...
I am a research scientist, and 50/50 hot water/ muriatic acid is exactly what I use.
A friend of mine suggested electrolysis (I havenít tried it yet).
1. Mix one tablespoon of washing soda for each gallon of tank volume. 2. Block the petcock holes and fill the tank right up to the filler neck so that all inside metal is covered with the water & soda. 3. Make an electrode out of something steel (a washer, a bolt, etc), connect a wire to it and put the electrode in the tank (make sure the steel or a bare section of the wire will not ground out against the tank). 4. Connect the electrode wire to the the negative side of a battery charger and attach the positive side of the charger to the tank.. 5. Turn on the charger and adjust your charging rate to 1 to 1-1/2 amps. You will see bubbles forming and the water will turn brown. Periodically clean off the electrode and let this process work at least overnight. 6. Turn off the charger, dump out the solution, clean and dry the tank (inside and out) and Itís time to coat it.
wow i thought i was a psycho for using muriatic acid but i guess theres other humans out there doing it with positive results! I get the warm fuzzys! I just saw the stuff layin around and thought hell im at my wits end and ready to buy a new tank. Im just gonna do this and see what happens, low and behold it worked. I did nutralize it by washing it out many times afterwards. cant remember what i used to wash it out after but it was something good, heh
I used pool muriatic acid but didnt water it down (sounds like a good idea)
Filled it halfway and swished it around good to cover all the area inside.
The process took about 30-45 minutes. then drained it and watched as all the nasties drained right down the tube.
Now the electrolysis idea sounds like fun to try just cuz it involves electricity and water I would probably be stupid and stand in a puddle while setting it up and toast me head real good heheh It sounds like a cool idea though, Ill do anything to get damn rust off the tank cept bang it with a hammer....
hey whatley i liked reading your "stay stock" writeup on that page you referenced, good stuff man brought a smile! Words of wisdom... Even though im looking for a cafe seat and some clubmans heheh (thats it i promise)
My neighbor who is a metalurgist said that all you have to do is fill the tank up with classic coke (the drink) and let it sit for a week. Then flush it out and you have a good rustfree surface. Anyone tried that? Steve in Ohio
"Now the electrolysis idea sounds like fun to try just cuz it involves electricity and water"....ROTFLMAO!!!! Good one! Thanx for the details on the muriatic acid. It's one of the most effective ways to clean the gas tank, but without knowing how to do it without ruining the tank, I've never tried it before.
Have heard about the electrolysis technique also & it's supposed to work very well. It can also be used for cleaning rusty parts in general. The chemical reaction draws the rust off the parts or whatever, at least that's how it was explained to me.
Steve, Never tried the Classic Coke thing, but I know for a fact that the Navy used to use Coca Cola for cleaning rust off the decks of ships back in WWII. (Wonder what it's doing to our stomach linings, LOL!)
Just remembered another one for cleaning smaller rusty parts. Just place 'em in a container of pure molasses & let 'em set for awhile. Not sure of the time needed, but it's supposed to work fairly well also.
POR-15 is a gas tank cleaner & coater, kinda like Kreem only better! There's probably a lot of shops that carry it or even a search on the Internet would probably have places that sell it on-line.
Got mine thru www.amr-of-tucson.com some years ago if they still carry it. They told me there was enough to probaby do 2 tanks, tho' I haven't even used it yet, LOL! Back then it was about $45-$50 per kit ?
Is it good to drink ? Hmmmm..I dunno, but it probably coats the internals better than Tums
Edit: Just checked the website & they still carry it...$30
Also saw a product there called "Metal Ready" for cleaning rust from gas tanks...$20
Both in the "Lubricants, Sealants & Cleaners" section.