help for rusted gas tank

[zedx11]

I'm stealing this from another site.

Originally Posted by kwright

I’ve been experimenting with using electrolysis for rust removal. The photo below was taken this weekend and shows the third fuel tank I’ve used this technique on, in this case, an S2A.

The sacrificial anode shows the amount of rust attracted after about 30 hours. I’ll clean the anode off after about 48 hours and continue the process until it comes out clean. My guess is, somewhere between 48 and 72 hours and the process will be finished.

Note the plastic spray can cap used as an insulator to keep the anode from touching the sides of the filler opening and as the mount for the anode. These plastic caps are just about the perfect size to slip over the filler opening.

Originally Posted by kwright

OK, here we go…

These are two links that I used to understand the electrolysis process.

http://twostrokes.com/Tech/html/electrolysis.html
Electrolytic Rust Removal

Also, below are several more photos from my current project. The first shows the process after about 54 hours. I expect the process is about complete, but I cleaned the anode and am continuing the process for another 24 hours to ensure it’s done.

The second photo shows the basic equipment; a battery charger, the (freshly cleaned) anode and the mix for the electrolyte. The Arm & Hammer product wasn’t particularly easy to find, but I eventually tracked it down at a very large mega-superstore (Meijers). It’s cheap so I bought two boxes – just to be sure I have a future supply.

The anode is simply a piece of ¼ inch threaded rod (zinc plated) that I bent into shape to fit into the tank WITHOUT touching the sides (most important!). Note that the anode doesn’t have to be plated, any cheap steel – or even stainless, will do. I simply had this rod around so I used it. Note the threading was an advantage as I could use nuts to mount the rod to the plastic cap.
The positive clamp from the charger goes to the anode, the negative to the item to be cleaned, in this case, the tank itself. To connect to the tank, I first measure the inside diameter of the petcock opening – about .600 if memory serves. I picked up a rubber “cork” at Lowes that was about this .600 size in the middle of the cork taper. I pushed the rubber cork/plug into the petcock opening, good and tight. Of course the tank has to be sealed before the electrolyte is added.

Using the nut that connects the petcock to the tank, I spun this nut onto the petcock threads, which was a perfect fit over the top of the rubber plug. Over the outside of this nut I placed a worm-clamp, inserting a piece of wire with the last inch or so stripped, under the clamp. When the clamp is tightened, the wire would be trapped between the worm-clamp and the large petcock nut. The other end of this wire is where the GROUND from the battery charger is connected to. If you look carefully in the last photo, you can see the ground wire/clamp on the left side. Note that the reason I used a worm-clamp over the top of the nut versus putting the clamp directly on the petcock mounting threads is I didn’t want to damage the petcock mounting threads in any way. The nut is designed to mount to these threads and protects them this way.

When turning on the charger I use the 12v, 10 amp setting. The charger started out at the high end of the scale, but quickly dropped to a low current flow. The last photo shows the setup/hookup.

I took a plastic paint can cap, and cut a hole in the middle using a hobby knife. The anode is mounted with washers and nuts on the top and bottom, to make sure it doesn’t shift at all. Look carefully at the cleaned anode, you can see where it’s been worn away… that’s why it’s called “sacrificial”…

Note that when you’re done, the steel inside the tank is raw and unprotected, and once the tank is rinsed out, it will tend to start rusting again. My coating of choice is POR-15, but that’s a personal matter.

Let me know what other questions you might might have...

[itch808]

Nice! I just finished using POR-15 on my tank, and while it worked great (did away with ~90-95% of the rust) I'd much rather work with water/washing soda than all those other chemicals.

[dsmack]

ZedX-11:
That is a very descriptive and well done write-up on using the electrolytic process to clean the fuel tank. It is something I think I will need to be doing during the inevitable "Winter Blahs" time here in the Northwest this coming winter.

The tank on my '91 ZR750 appears to be fundamentally sound, but beginning to show signs of some minor rusting. Is there a danger that this process will eat right on through the tank if it finds a weak spot? Does the sacrificial anode deposit new metal ions on the interior or the tank through a type of plating action?

If the rusting is, in fact minor, would I be better off to use some other process instead?

Thanks for answering my questions... this is a new process for me, and I'll spend some time looking over the links you so kindly provided.

Thanks again for taking time to write this up and take the very nice photos of the project.

Don

[zedx11]

sorry but you missed the first line of the post.

I'm stealing this from another site.

you will have to wait for someone a little smarter than me or do some more research of your own.

[zedx11]

it's probably that time of year again for people needing help with some project bikes so here's a bump for you guys.

[Mercury]

if i can suggest - after the tank is completely dry after doing this process... coat it with very good primer... pour some of this stuff in the tank - masterseries silver primer...

shake it all around then pour out the excess... allow it to dry at least a few days

it will never rust again

PM Industries MasterSeries Coating Line - Rust Preventative Paints & Coatings For Less!

kenny

[Baitis]

The MasterSeries doesn't mention anything about alcohol fuels. The coating is urethane. I had a urethane coating in my tank when Maryland went to E10 gas several years ago. The urethane made a mess of my whole intake system, including the valves. I used a Bill Hirsh product in the fuel tank after tearing down my engine (ZL600 Kaw).

[Mercury]

Originally Posted by Baitis

The MasterSeries doesn't mention anything about alcohol fuels. The coating is urethane. I had a urethane coating in my tank when Maryland went to E10 gas several years ago. The urethane made a mess of my whole intake system, including the valves. I used a Bill Hirsh product in the fuel tank after tearing down my engine (ZL600 Kaw).

Call the number on the website - talk to chuck... i met the guy a few times he knows his stuff, has been doing it most his life and has dealt with all sorts of fuels, diesel, leaded, gas....

he is honest and if it wont work he will tell you... but just because it does not say anything about achoal fuels does not mean it will breakdown with them.

I painted my whole truck bed with the stuff... i have tested gas, oil, brake fluid, hydrolyc, diesel and paint thinner with no harm done to the primer... of course its only a small section i try it on not a tank... but just saying

kenny

[leadfingers]

To bad zedx11 is banned, I wanted to ask what ratio of Washing Soda he used.
The original site he linked to suggested a ratio of 1 Tablespoon per gallon but that didn't work very well as the amperage wouldn't get above 3A.

For anyone thinking of trying this, this is what I did and what I did wrong.

91 Vulcan 1500 with 3.7 gallon tank, heavily rusted, had ~1gallon of old gas setting in it for several years. (don't blame me I just bought it)

Found the Washing Soda at Winco with the laundry soap.

I happened to have a piece of 3/8 stainless allthread begging to be used so I didn't bother to get the 1/4 standard steel rod ... mistake #1. The stainless didn't work as well as standard steel rod (the properties of the Stainless make it less desirable for a anode), plus the 3/8 was harder to bend into the shape I needed to fit down the neck of the tank and still clear the bottom.

I rinsed the tank out 10 times with soap & water and 5 times with just water. Of course it still smelled like 3 year old gas. I started out with the recommended ratio of 4Tsp per tank ... filled the tank 1/2 full, dissolved 4Tsp Washing soda in 2cups hot water, added that to the tank, then filled it up the rest of the way. Turned on the 3A charger and walked away ... Mistake #2. Make sure you use at least a 10A charger.
I came back the next day and saw it had almost no rust on the rod, swore to myself and went out and bought a 10A charger. Hooked it up and waited for the meter to rise, when I saw it wasn't going past 3 amps no matter how long I waited, I turned it off and used a turkey baster to take 2C out of the tank. Dissolved 4 more Tsp of washing soda in 2C hot water and added it to the tank. When I finally got the amperage to 10, I had used a ratio of 4 Tsp per gallon. Let it run for 3 days, cleaned off the rod and drained the tank. It was still looking pretty bad inside so I filled it back up and started out at 16Tsp. On the second go-around I cleaned the rod every day and adding more washing soda to keep the charger close to 10A.

I called the POR-15 people and found a place fairly close that sells the tank sealer, will use a good coat of that once the tank is dry.

Not counting the charger, total cost $35.
Not a quick procedure but pretty cheap and fairly easy.

[crawfish]

Hello All,

I have a tank that I only want to remove some minor rust using this Electrolysis method. Is there anything else that I can coat/seal the tank with once the process is complete. My first attempt at this removed probably 90% of the rust and I thought I had it dry and when I looked at it the next day it was covered with rust dust agin. Any suggestions, as the rust content is not that bad.?

THanks.

[Mercury]

Originally Posted by crawfish

Hello All,

I have a tank that I only want to remove some minor rust using this Electrolysis method. Is there anything else that I can coat/seal the tank with once the process is complete. My first attempt at this removed probably 90% of the rust and I thought I had it dry and when I looked at it the next day it was covered with rust dust agin. Any suggestions, as the rust content is not that bad.?

THanks.

post #6

kenny

[leadfingers]

I used the POR-15 tank sealer and am pretty happy with it.
They sell it as a stand alone sealer, in 8 oz (~$17) and 1 pint (~$28 ) or in a motorcycle kit for about $87. The kit comes with 8 oz of the sealer, Marine Clean tank wash additive, and a bottle of metal prep. The local distributor here carried the 1 pint size so that's what I got. It easily has enough to do 2 tanks.
The results look like someone mixed silver metal flake paint with clear fingernail polish, it gives you a thick hard finish that covers incredibly well. Will fill pin holes in a single pass and 3/32" holes in 3 passes. While it's not cheap stuff, for what it does it's a bargain.