With nothing but a battery charger and my girl-power, I solve a thorny rust removal problem.
As you can see, the underside of my rear fender has a lot of surface rust and is very pitted. To remove this rust, I have a few options. I can remove it mechanically, using a wire brush or a sandblaster, however, I would run into a few problems.
First problem: There is a few tight corners where it would be really hard for me to reach all the rust. Two: I might heat the metal to a point where it warps, and Three: I might thin down the metal too much.
I could also remove the rust chemically, however, that also has a few problems. The first problem is that it’s not environmentally friendly to dispose of the wastes. The second problem is that it’s fairly costly. If I were to use the best solution of chemical removal, it would have to be half vinegar, half water. And even for me to fit this fender in that solution, I would need 375 gallons, and that would cost me about $500.00. And also, even that, with removing it, I would kill a lot of fish here in Teddyland. And no teddy bear wants to go without fish for dinner.
So let me ask you. What would Chris Hemsworth do?
[Sound Effect] “Schaaaa-wing!”
Chris Hemsworth would use electrolysis.
For electrolysis, you’re gonna need a few key ingredients. First is, obviously, your rusty piece of metal. Second, a car battery charger. Third, your water tank. Fourth, a sacrificial piece of metal, and this piece of metal needs to be cast iron or steel. No stainless steel, otherwise you’ll introduce chromium to your water tank. And hexavalent chromium is a terrible way to get cancer! Fifth, you’re gonna need a form of electrolyte to make the water more conductive. Normal table salt will do, as well as baking soda or sodium bicarbonate. However, the best to use is sodium carbonate or normal washing soda. You’re gonna need about a tablespoon per gallon, and for my 375 gallon tank I needed about four boxes.
Before I start, I’m gonna use dish soap and water to wash any excess oil off the part.
And now I’m gonna submerge it in the tank.
I’m gonna put my sacrificial anode in to where it has line-of-sight to all the most rusty areas of my part and to where it can’t touch the part. For your electrical connection, you don’t want to use anything other than steel or cast iron because any other metal will introduce ions to the solution that will cause problems. So I am using a steel coat hanger instead of a copper wire to connect my piece.
I’ve hooked my positive lead from my car battery charger to my sacrificial anode, then my negative to my car part. Once the electricity starts flowing through this, it’s gonna create two different reactions. The first reaction is when the water molecules’ hydrogen and oxygen are gonna be breaking apart. The hydrogen is gonna be bubbling off of the cathode, then the oxygen is gonna be bubbling off of the anode. Now children, don’t do this in your basement because the hydrogen will also go into the air, and hydrogen is a very flammable gas. And, it is a terrible way to blow off all your limbs! Now, the second reaction is the most important, and the reason we are doing this.
This rust, or ferric oxide, or Fe2O3 is an unstable compound. And so once the electricity starts flowing through this, it’ll become magnetite, or Fe3O4, and become a stable compound.
If you look really carefully along the edge, you can see the bubbling of the hydrogen coming off the cathode. You can also see the oxygen coming off the anode.
It’s been about 5 and a half hours, and as you can see, the water’s nice and foggy with pieces of paint and rust that have flaked off. And the corner of the piece itself has some black where the magnetite has replaced the rust and where the rust is falling off.
Once I got the fender cleaned up, I could still see a tiny bit of rust in the deep pits, so I put it back in to cook overnight.
Here’s a before-and-after of a piece that I have finished and then a piece that I haven’t. These two rear fenders were in roughly the same condition before I started, so you can see that the electrolysis worked really well. I had to use an older car battery charger because the newer one wouldn’t let me run any amps through it unless there was an actual battery connected to it.
I ran my car battery charger at 100 amps, and realistically, it was nearly done at five and a half hours. So if I left it in for seven hours, it most likely would have been completely finished. So if you ran yours at 10 amps, it would be done in about two days.
See ya next time, kids, on Hanna’s Bug!
As always, this show is filmed in front of a live studio audience.