Rust in gas tank?

#1
What is best way to remove rust build up in Fox gas tank? I've already filled with rust remover and let sit for about a week, it removed some of it but still a lot of rust buildup inside. Outside chrome is fine.

Thanks for any ideas
 
#2
I always took marbles or nuts and rolled around inside to get what rust I could then coat it with POR…todays times I’d fill it with evaporust let it set 2 days and it should look like new…rinse very very well slosh around some gas or kerosene in it and put it in service….
 
#3
.

Thanks for any ideas
I've tried probably every method available over the years, some with great success and others with nothing gained but wasted time.

The most success I've had was finding a local machine shop that does it commercially, I've used them for everything from minibike tanks to full size car ones. Price may vary by size but every one I had done was worth every penny, they got them way cleaner than I would ever have. The last Fox tank they did was around $60 bucks? IIRC. Also try searching radiator shops in your area.
 

1971_MB1A

Well-Known Member
#4
What is best way to remove rust build up in Fox gas tank? I've already filled with rust remover and let sit for about a week, it removed some of it but still a lot of rust buildup inside. Outside chrome is fine.

Thanks for any ideas
You could carefully try muriatic acid. (read up on it first) I've used that before and it usually works very well but don't leave it in too long as it will literally get so hot that it will burn the paint on the outside of the tank. Once it is clean you can neutralize it with baking soda and water then rinse it well and let it dry then spray the inside of it with fogging oil to help keep it from rusting again until you are ready to use it.
 
#6
Thanks for the great ideas! I forgot the name of rust remover I let sit for around a week until it was mentioned in this thread, it was evaporust. Like I said it worked some but still a good amount of rust (see attached pic).

I will try the other suggestions.

Thanks again!

DSCF1380[1].jpg
 
#7
I have used and recommended the use of muriatic acid over the years here. What seems to be missed is that I dilute it down to about 5:1. It eats metal, and with non-ferrous metals, produces hydrochloric nuclear bomb gas. I still use it diluted, but for motorcycle tanks I've started using good old fashioned electrolysis.

I make a sacrificial anode fixture that allows me to keep it isolated from the tank, but gets the anode far enough into the tank to do some good. To that, I hook a positive battery lead. (Motorcycle batteries work pretty good) The ground goes to the tank, and for electrolyte I use washing powder soda or phosphoric acid mixed up from a powder.

Sounds more complicated than it is, but I do 50 year old MC tanks like this, then follow up with Caswell's Epoxy sealer. I've heard all about POR and Kens, and everyone has their favorite, but Caswells is mine. It isn't cheap, and nothing I said above is what I do, not what I've read. Well, I did read about it before trying it, and I've tried a lot of things to get rid of rust. The reason I now use electrolysis instead of muriatic acid reductions is that I've put holes in valuable tanks with the acid. It's faster sure, but it can do some damage. I still use acid for a lot of stuff though.

Here's a pic. Anode was 1/4" rod, welded into an "L" and jammed in a hole in 2X4. 12VDC batt, I kept a charger on it, and my volt meter, just to monitor charge voltage because I was curious about amperage draw. (I = V over R)

Tank Electrolysis.JPG
Paint2.JPG
 
#8
That electrolysis procedure is really cool! Thanks for all the detailed info in your post.

Just to be clear the tank is filled to the top with phosphoric acid solution and anode in solution but not touching tank? How long is this process?

Thanks again!
 
#9
Yes, I fill it as full as I can get it. The reason I like the phosphoric is that it leaves a black film that seems to be protective. Depending on the amount of corrosion, you'll be changing electrolyte often- once a day anyway. Keep old towels etc under it all to catch the nasties that roil out of the filler hole. You'll never get it perfect. Well, maybe you will, but I rack a disciprine, and shut the process down before it's clean as a whistle, because I know I can dump in some Caswells and cover everything forever. NOTE: I have not tried POR15 and it is highly recommended on the net and here by people who know what they're doing. I'm just in love with using catalyzed epoxy, and if you reduce it down a tad with rubbing alcohol, it thins it out. Also, despite dire warnings, I routinely use half batches out of the $50 motorcycle kits, saving the remainder and using it months later with no ill effects. The stuff is expensive after all. A bit more than two cents worth, but still ash tray change. Plan to spend a weekend with the process, but you dont have to stand over it.
 
#10
Wow some good info here. That tanks looks rough. I’ll just add what I did to my tank that wasn’t as bad as yours. I filled mine with vinegar. Just white distilled vinegar from the grocery store about 3 bucks a gallon here. I filled the tank and let it sit for a week. I then poured fish tank gravel in the tank and shook it ALOT. Empty the gravel and repeat. I did this a few times over a few weeks and it came out mint. I used the smaller more jagged gravel as opposed to the more rounded stones. last thing to do is fill it with water and some baking powder for about 20 min to neutralize the acid from the vinegar
 
#12
Thanks again everyone will report back on how I make out.

I reported the last post with all those spam links from new member "toms23roy". Hope the admin deletes their account. These ASSHOLES will never learn.
 
#13
When I have a Tank that has RUST inside and hard to remove.I tank it to the Radiator shop.They do this all the time.I recently
brought the tank there. The will pressure rise it and if you tank has seams they will sweat solder all the joints.They charged me
$42 for a 12'' x 4'' Tank for all of the above.
 
#14
I've started using good old fashioned electrolysis.
My wife has a 50ish gallon barrel for doing electrolysis here at the house and it works amazingly well on stuff. The hardest part was finding an old battery charger that would work well with it. I definitely recommend setting one up if you deal with lots of rusty parts/junk.
 

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#15
The hardest part was finding an old battery charger that would work well with it.
Heck yeah! The new "smart chargers" don't like to supply voltage when they don't feel a load. In my case, I got this run down Yamaha with an expensive battery that my charger said was bad. So I kept the charger on the battery, red lamps and all, and then applied the pos and neg leads to the tank and anode and just rolled with it. I kept my voltmeter hooked to it, and over time, the damned charger actually started charging the battery, and now suddenly I no longer have a "bad" battery! It now sits in the restored Yamaha, keeps a charge, and everything is hunky fricking dory! LOL, those who have these smart chargers and see their relatively new batteries fail will appreciate this.

So I recommend a battery for anyone doing this, if nothing else to maintain steady voltage, and it should trick your new smart charger into getting with the program, no matter what it thinks.

If I could only convince HP that my printer really does need new ink, despite the lies my printer is reporting via my band width to HP, who has taken control over my printer, and probably my smart charger, and several GFI outlets in the garage. (Psychic Spies from China)
 
#16
Heck yeah! The new "smart chargers" don't like to supply voltage when they don't feel a load. In my case, I got this run down Yamaha with an expensive battery that my charger said was bad. So I kept the charger on the battery, red lamps and all, and then applied the pos and neg leads to the tank and anode and just rolled with it. I kept my voltmeter hooked to it, and over time, the damned charger actually started charging the battery, and now suddenly I no longer have a "bad" battery! It now sits in the restored Yamaha, keeps a charge, and everything is hunky fricking dory! LOL, those who have these smart chargers and see their relatively new batteries fail will appreciate this.

So I recommend a battery for anyone doing this, if nothing else to maintain steady voltage, and it should trick your new smart charger into getting with the program, no matter what it thinks.

If I could only convince HP that my printer really does need new ink, despite the lies my printer is reporting via my band width to HP, who has taken control over my printer, and probably my smart charger, and several GFI outlets in the garage. (Psychic Spies from China)
That's good to know. I work at a Harley dealership and have a pretty much endless supply of bad batteries if I ever need one.
 
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