Topic: Rust removal

[beemerbum]

I found a gallon jug of phosphoric acid in my shop. I'm presuming it is full strength. I would like to de-rust a rear brake lever for  a K1 750. Any advice on dilution, if necessary, to remove rust using this stuff would be appreciated. I know that Coca Cola contains phosphoric acid and has been used to remove rust in some cases for chrome fenders and such.

[MauiK3]

Not sure, maybe test 50/50 on a rusty bolt?

[Floshenbarnical]

Personally the only way I’ll ever de-rust anything ever again is by using electrolysis; it does a real number on the rust and leaves non-rusty method unscathed.

It’s very simple. You use washing soda to make a solution, and use your rusty bit at the positive end and a piece of iron at the other electrode and switch it on. The iron gets rusty, the rusty part gets clean. And it doesn’t damage anything that isn’t rusty.

[BenelliSEI]

It’s probably not 100%. The “Milkstone Remover” I use (farmers use it to clean milking equipment) is very effective at 12:1 (12 parts water). Iuse it for a long time and then toss it on the lawn. Causes no harm.

[Redline it]

Personally the only way I’ll ever de-rust anything ever again is by using electrolysis; it does a real number on the rust and leaves non-rusty method unscathed.

It’s very simple. You use washing soda to make a solution, and use your rusty bit at the positive end and a piece of iron at the other electrode and switch it on. The iron gets rusty, the rusty part gets clean. And it doesn’t damage anything that isn’t rusty.

that's 120v? and i wonder what the phosphoric acid would accomplish if it were the electrolyte, without dilute. i'm sure someone has tried it.

[Floshenbarnical]

Personally the only way I’ll ever de-rust anything ever again is by using electrolysis; it does a real number on the rust and leaves non-rusty method unscathed.

It’s very simple. You use washing soda to make a solution, and use your rusty bit at the positive end and a piece of iron at the other electrode and switch it on. The iron gets rusty, the rusty part gets clean. And it doesn’t damage anything that isn’t rusty.

that's 120v? and i wonder what the phosphoric acid would accomplish if it were the electrolyte, without dilute. i'm sure someone has tried it.

120v 6amps I believe. I used a car battery charger.

[BenelliSEI]

P.S. the Milkstone Remover is listed as 50-60% acid so I’m really using 1 part acid to 20-24 parts water. Try your stuff at 12:1. It won’t hurt anything. Always add the acid to water and not the other way around (safer procedure). Wear eye protection.

[beemerbum]

As always, this site is a great source for information. Thanks for the replies

[Floshenbarnical]

P.S. the Milkstone Remover is listed as 50-60% acid so I’m really using 1 part acid to 20-24 parts water. Try your stuff at 12:1. It won’t hurt anything. Always add the acid to water and not the other way around (safer procedure). Wear eye protection.

Great advice. Also wear hand protection.

And if you do use electrolysis, make sure you disconnect the terminals at the charger end and not the electrode end, or you could cause a spark and detonate the hydrogen accumulated in the headspace and dramatically soak yourself through the gas cap hole

[MauiK3]

Almost any DC voltage works but a 12v battery charger is probably your best bet.

[Alan F.]

The less 'smart' of a battery charger the better.

[RAFster122s]

Smart chargers tend to fail to provide any voltage or current as they detect a potentially deadly situation so instead of being responsible they go into a preprogrammed safe mode and start flashing their fault led and doing nothing else.  Thus why you want a charger with little to no “smarts” as the others are recommending.

You will have to periodically clean off the positive anode to keep the electrolysis working. Turn off power before pulling the sacrificial anode from your gas tank. Replace and one test you can quickly tty before you connect your wires to the power source is check for continuity or check the resistance of each wire connected the reading should be the over range value or resistance should be a very large resistance reading. The positive to tank’s bare metal spot so you get an actual value.  I think i

[pjandrew99]

I used 3 parts water to one part phosphoric acid. Worked great and I have reused it a few times with success.

[newday777]

The less 'smart' of a battery charger the better.

I actually have successfully cleaned a couple dozen tanks using a 3 amp smart charger, but I hook it to a shop battery, then have cables from the battery to the tank ground and to the anode rod (bolted to a plastic cup so there isn't direct contact with the metal of the tank and the anode rod.
Yes you have to clean off the rod every 6-8 hours to have the effective cleaning of the rust.

In this case of cleaning rusted bits, you have to hook up the negative alligator clip to the back brake rod/arm surgery submerged in the solution in a plastic bin, with the anode rod draped over the bin edge into the solution so it doesn't touch the metal part.(like in the anodizing videos)

[RAFster122s]

Stu,  huh, I would never have thought of that but, if you Do Not have a shop battery or a battery that the smart charger likes or would work, then you will need to make a battery it can or safe a weak MC battery to fool the smart charger or forgo the core on an old auto battery to have a tatters for your shop…

I know you can fool Costco Nitrogen inflation if you are quick enough by starting the inflation on one tire with enough air then quickly pop it and go to your flat or mostly deflated tire.
FWIW
Don’t know why you might want to know this as Costco doesn’t sell MC tires. 🙄

[Floshenbarnical]

The less 'smart' of a battery charger the better.

I actually have successfully cleaned a couple dozen tanks using a 3 amp smart charger, but I hook it to a shop battery, then have cables from the battery to the tank ground and to the anode rod (bolted to a plastic cup so there isn't direct contact with the metal of the tank and the anode rod.
Yes you have to clean off the rod every 6-8 hours to have the effective cleaning of the rust.

In this case of cleaning rusted bits, you have to hook up the negative alligator clip to the back brake rod/arm surgery submerged in the solution in a plastic bin, with the anode rod draped over the bin edge into the solution so it doesn't touch the metal part.(like in the anodizing videos)

That's the move I used. I grabbed the battery from my lawnmower and hooked it up in parallel. The charger still beeped if there was a fault, which in this case meant that the iron rod was touching the inside of the tank, which is can not do for the system to work. If you are not using a smart charger, then you can tell if it is working because little bubbles will start flying off your iron rod.