4 Attachment(s)
cleaning heavy rust from parts
I want to share my favourite method for removing heavy rust. I think I have tried all the common techniques even using chelating agents.
My favourite is electrolysis and I have tried many different witches brews, here is my favourite.
It is simple, get a 5 or 6 gallon bucket and fill 2/3 full with water. Added 10 lbs sodium carbonate ( aka washing soda, soda ash) ****avoid using baking soda or sodium bicarbonate they are NOT the same*****. Inexpensive sodium carbonate can be purchased at a pool supply store. it is used as a buffer to lower pH. I believe I paid approx $8-10 for 10lbs. I have use mine for over a year now without replacing the soda or electrode.
Add all the soda ash to your water, you want it saturated and you want some white powder sitting on the bottom. Grab a clean piece of steel as your positive electrode and place at one side of the bucket. Connect the red positive clamp from a battery charger to the this steel electrode. Place the charger away from the bucket in a safe place where it can't fall into the bucket. Be safe, you are using electricity.
We are now set up. I recommend to remove any grease from the item to be cleaned. I use mineral spirits and allow to dry. If big chunks of rust can be removed easily, do it now.
Grab a heavy stiff wire like a piece of coat hanger and dangle the part in the solution on the opposite side of the bucket than the red electrode. Connect the black negative charger clip to the stiff wire for the part to be cleaned. Make sure your parts DON'T touch the steel electrode (red/positive). Plug in the charger and I use 6V which draws 5 Amps with my setup and I leave overnight. I find 12V creates too much foam. Small parts can be placed in a small deep fryer basket, for example
the good news is the Fe+3 ions are reduced by the electrons from the negative power supply/charger to produce iron metal as finely divided black powder at the metal/rust interface. After 6-10 hours or so I unplug the charger and clean the parts up with a stiff brush and usually all the rust just falls off. At times, I may need to repeat on some parts. I usually dry the parts after washing to reduce quick flash rusting of the fine iron particles. A quick coat of oil and we are good to go.
BTW, this method does not corrode your parts like some other methods.
Re: cleaning heavy rust from parts
I've always wanted to try this.
Re: cleaning heavy rust from parts
Re: cleaning heavy rust from parts
Quote:
Originally Posted by
bamman
I've done this on my engine block. It works well.
I assume the strong solution damaged the aluminium intermediate bearing.
Re: cleaning heavy rust from parts
pointing out with acids etc one needs to be carefull what you dip
spring steel and hardened steel are no no's
in fact I killed the little coil spring for the hood on one of my projects just by soaking it in liquid drain cleaner & water for a couple of hours
not springy .. not at all
very brittle infact , if I'd soaked it all night it very probably would have shattered like glass instead of just 4 or 5 breaks in the coil
(wow , chemistry..)
in my group of acquaintances there is a set of front spindles for a front disc satellite or road runner that need scraped - BECAUSE someone acid tanked them so the hardening is likely questionable now
Re: cleaning heavy rust from parts
I tried some of this, and was very impressed. I too have always wanted to make a setup like in the OP. If I ever have something very large which I need to aggressively clean, I'll probably make one still.
https://www.youtube.com/watch?v=SEDgOBK_L70
Re: cleaning heavy rust from parts
Quote:
Originally Posted by
chromguy
I assume the strong solution damaged the aluminium intermediate bearing.
Perhaps.
I got it re-bushed it after cleaning the block. Didn't want to risk it.
Re: cleaning heavy rust from parts
Quote:
Originally Posted by
bamman
Perhaps.
I got it re-bushed it after cleaning the block. Didn't want to risk it.
You can coat any part with asphalt or similar to protect a critical area, this is a similar idea to what is done in the plating business.
Re: cleaning heavy rust from parts
Evapo-Rust. $15 at PepBoys. Can't beat it.
Re: cleaning heavy rust from parts
Quote:
Originally Posted by
cqlink
Evapo-Rust. $15 at PepBoys. Can't beat it.
It does work well, but does not last long when cleaning heavy rust.
Re: cleaning heavy rust from parts
I have been doing this for years, cheap and effective. All said and done the waste slop goes over the back hill because there are no chemicals to concern with.
Re: cleaning heavy rust from parts
I don't know what I'm doing wrong, but so far I haven't had much luck with Evaporust. I used it on the large washers that hold the front fender liners behind the front bumper on my F-150.
Re: cleaning heavy rust from parts
Quote:
Originally Posted by
supercrackerbox
I don't know what I'm doing wrong, but so far I haven't had much luck with Evaporust. I used it on the large washers that hold the front fender liners behind the front bumper on my F-150.
For a moment let me do the chemist thing (yes I am a chemist). So I have a gallon (3.78L) of EvapoRust and according to the SDS (Safety Data Sheet aka MSDS) it contains 16% of the chelating agent. Check wiki for details on this. So the gallon contains 3780 x 0.16 = 605g grams of agent. If they use EDTA it has a mass of 372g/mol and iron is 56g/mol it will consume 56/372 x 605 = 91g of iron ions. This is approx 130g corrected to rust, as it is usually the red-brown Fe2O3. The EvapoRust is not fussy and it attacks all rust and will eat the entire flake of rust. This is why it is best to remove as much rust by other means, if you have a large part with lots of rust.
I specifically used the title heavy rust as electrolysis process above does not attack the bulk rust. It converts the rust at the metal/rust interface back to finely divided iron metal (it looked black). This can only occur if the solution can penetrate the rust which is usually easy BTW. Now that the rust is converted at the surface, the flake of rust is removed by the bubbling process or when you use a vegetable brush or similar.
The downside of electrolysis is that it is a line of site process and as such is not as effective at getting the rust out of small grooves for example.
After the electrolysis, if I want the part cleaner in crevices etc, I will then use the EvapoRust.
