Topic: Electrolytic Rust Removal From A Motorcycle Gas Tank.... anyone see this?

[johnrdupree]

I wanted to learn how this worked so I did a test with an old saw I had laying around.  Pics of the process:

I bought a sheet of steel at Lowe's and cut it up into sections that would fit in a plastic bucket.  Also shown is the washing soda I used.  I can't remember what the concentration was, 1/4 cup per gallon of water, maybe, but it isn't exactly critical.  You just want to reduce the resistance of the water.

The anode in the bucket.  I was trying to get it set up so there would be no "blind spot."  If I had used only the section in the back and not the sides, only the rust surface facing it would have been cleaned.  The side facing away would have remained rusty.

The test piece.  I cleaned it with soap and a stainless brush to get the sap and goop off before the electrolysis.

The setup.  Saw in the water, not touching the anode.  Negative lead on the saw, positive on the anode.

Another view.  I had to keep the saw away from the anode, hence the piece of wood.

Making hydrogen.  This is after a couple of minutes.  I let it go for about a day and at the end the surface of the water was covered with rusty, brown scum.

The result.  When the saw came out of the water it was covered in a black film.  Warm water, soap, and a stainless brush gets rid of it and you're left with bare metal.

It works, it's cheap, and it can clean large areas of heavily rusted, oddly shaped items while you do something else, like clean carbs or paint your swimgarm.  It is a line of sight process so setup is important but not hyper critical.  The inside of a tank might be tough to do because you need to make sure the anode can see the entire inside of the tank but not touch anything.

Keep in mind, though, that like all rust removal processes it will not fill in pits in the base metal.  Once the rust eats away the original surface, that surface is gone forever and, if necessary, will have to be replaced by bondo, lead, welding, whatever.  Between this, oxalic acid, and naval jelly you should be able to de-rust just about anything a scabby old bike throws at you.

Good Luck,
~john

[xsmooth69x]

so other than being cheap if you already have a battery charger is this a good way of doing the de rusting? i never heard of half the products just listed above or never worked with it.

is it as good as the electro?

[Dyrden]

I suspended the anode(rebar) from fishing line rigged above my tank which was submerged in a plastic trashcan.  I lined it up so it went through the opening for the fuel injecting pump.  Worked like a charm.  I then put the tank in my oven on low to dry it quickly.

[BobbyR]

I'm currently de-rusting the tank for my K6 project, it's a beautiful dent free OEM Valley Green (?) K4 tank but sadly, inside there's more rust than steel.

I used the tank cleaner from my POR15 kit but that hardly put a dent in the huge amount of rust inside it, so I thought "nothing ventured, nothing gained", so I used an old engine mount bolt (the long one) as the anode, filled my tank with a washing soda mix, and hooked up my crappy little 2.5 amp battery charger.

Now being that most articles here and on the interweb talk about using 8+ amp chargers (in contradiction to the linked article above, surprisingly) I wasn't expecting much, so I was pleasantly surprised with the large amount of rust I witnessed hanging off the anode only a couple of hours later!

Don't get me wrong, I'm only just noticing clean metal inside the tank now (on the anode side of the "hump" mostly) after 5 days of electrolysys so I might well need a bigger charger, (actually I bought a 16 amp charger on EBay but it's one of those stupid automatic "smart" chargers and it won't work on my electrolysys rig at all, so I wasted 105 bucks, bugger it...........) but regardless, it's producing a better result than the acid did. Cheers, Terry. 

Save your money Mate and hook it to a car battery.

[Lostboy Steve]

is that dog ok? I like this a lot. I just recently (last week) used the por15 system for the second time. I had a tank that sat with gas in it since 1991. I had a little acid (metal ready) left over from a previous tank, so i threw it in and rolled the tank around every few hours for 3 days (nevermind the directions on the label). After that i did all the things the instructions say to do. I even boiled water to mix with the marine clean for the wash phase. This tank came out looking brand new inside. I would have loved to use this system though, looks simple enough. Also looks less time consuming than my 4 day method. The carbs also had all that goodness in them, so i sank them in lacquer thinner for 2 days and then boiled all the parts in vinegar once I was able to disassemble. All in all my way worked but I would have loved to save some time.

[gnarlycharlie4u]

Here is a link on the electrolysis method. While he built his own power supply, a car charger will do the same thing.  http://www.landyzone.co.uk/lz/f38/rust-removal-using-electrolysis-63065.html

HAHA YES!!!

This is the same thread I read when I learned how to do it!

I just started a  fresh electrolysis run on my goldwing tank.
Here's some pics:

http://gnarlywrench.blogspot.com/2011/07/gl1000-gas-tank-removal.html

[Terry in Australia]

Save your money Mate and hook it to a car battery.

Thanks Bobby, I did think about just hooking up my jump starter pack thingy to it, and I still may. I've been away for a couple of days and while I was out in the country I drove by a chemical supplier, so I bought a 5 liter bottle of milking machine cleaner, that has 1100 grams of Phosphoric acid per liter (strongest one they sell) so I took it home, diconnected my battery charger, (there was a heap more rust hanging off the anode) dumped the electrolytic solution out (the tank looked cleaner inside, but still lots of rust) and refilled it with the acid and around 13 litres of water, put the tank inside a big plastic tub and left it overnight.

Good thing I put it in the tub too, because this morning there was more acid mix in the tub than in the tank. I'd forgotten that when I did the electrolysis process I'd sealed the petcock hole (and a couple of pinholes in the bottom) with aluminum tape, and it had obviously eaten thru the aluminum. Tonight after work I'll dump the remainder of the acid mix out and see how the inside looks, this tank is really rusty so will certainly need some repairs, but it's a dent free OEM paint tank that I could almost use (I say almost because there are a couple of surface rust spots on top too, sadly) without repainting, and I've never owned a green CB750.

If it's almost clean, I may try the electrolysis again, even though my setup with my pisssy little 2.5 amp charger is as slow as a wet week in winter, I can't do much until some more parts arrive, so I've got plenty of time. Cheers, Terry.

[stampederunner]

I had excellent results using rebar, a aresol carb cleaner cap and a small piece of rubber hose. I bent a piece of rebar in a "L" shape to fit in the tank cap and extend the length of the tank. Put a piece of rubber hose on the end of the rebar so it doesn't touch the tank. Then I poked a hole in the center of the aresol can cap to support the rebar and to keep it from touching the tank I also drilled multiple vent holes in the cap. I used a small piece of bicycle tube and duct tape to seal the petcock. Filled with water and washing soda and hooked it up to my battery charger set at 12v for only 5 or 6 hours.

Like others have said it is a line of sight procsess so I think the rebar extending into the tank is critical.

[johnrdupree]

I had excellent results using rebar, a aresol carb cleaner cap and a small piece of rubber hose. I bent a piece of rebar in a "L" shape to fit in the tank cap and extend the length of the tank. Put a piece of rubber hose on the end of the rebar so it doesn't touch the tank. Then I poked a hole in the center of the aresol can cap to support the rebar and to keep it from touching the tank I also drilled multiple vent holes in the cap. I used a small piece of bicycle tube and duct tape to seal the petcock. Filled with water and washing soda and hooked it up to my battery charger set at 12v for only 5 or 6 hours.

Like others have said it is a line of sight procsess so I think the rebar extending into the tank is critical.

That sounds like a fantastic method.  All I would be concerned with is the tunnel casting a "shadow" onto part of the tank bottom, but that should be easy enough to work around.  For those who are going to try this, keep in mind that the surface area of the anode is part of what determines how quickly this works.  Even with rebar running the length of the tank it will have way less surface area than the inside of the tank.  It will eventually get it done, though.

stampederunner, how did you deal with the black residue after the electrolysis was finished?

~john

[bender01]

I have done it with rebar,salt water and a battery charger. I did mess up and touch the inside of the tank. It was tack size hole quick. But it was clean!

[Terry in Australia]

Well I dumped the phosphoric acid out of the tank and the tub last night, and it's working well. The vast majority of the rust is gone, but there are a few more pin holes than I'd hoped for, including one on top of the tank, about half way between the seat and the filler cap.

I refilled it with acid overnight and once I get back home tomorrow night (Army Reserve training this weekend) I'll give it a final wash out before I seal it with POR-15. I'm keen to try the electrolysis method again on another rusty tank I've got that's not as bad as this one, but I think the amount of rust in this tank was too much for my little 2.5 amp battery charger set up. Cheers, Terry.