Ok, here are some photos as promised. In the end I left it on for around 12 hours. It seemed to work very well to me , but of course experimentation may reveal a better mix/time etc. The weakest link was my battery charger - you need an old one so it doesn’t have safety features, but mine had no ampage switch and the dial was broken.
Tank setup - 4 anodes from old steel bar linked together with wire, this is where the ‘+’ will connected. The rack on top will be used to hang the objects on with steel hooks , this is where the ‘-’ will be connected.
Now with water/soda crystals in 3.5 Litres to 1 Tablespoon of soda crystals.
After about 1 hour - notice I’ve added crocodile fly leads from the first anode - I found by clipping the other end to anode 3 it kinda woke anode 3and 4 up a bit - they were less active before.
I also added the knife at this point, and connected a fly lead to that as well for good luck lol!
After about 6 hours things were really starting to happen!
Sadly I forgot to take most of the parts pre the experiment…. but I did get some of the gears, which were the least rusty bits……
And some of the finished bits, just lightly scrubbed in hot soapy water with a scourer and dried in the oven - you really need to do this or it starts to rust very quickly. I have oiled it all up now.
The rust basically comes off and leaves a black stain, which just washes off. This next part was completely encrusted with rust before the process, like you couldn’t see any of it. You can see the ‘shell’ of rust that came off in the gloop on photo 4 above.
This big chuck came up rather nicely too.
These final two are of the old knife, only half of it went in - it will go in for another dip to get the rest off - you can see it took it back to steel virtually after decades of rusting.
When I get some time I’ll clean all these bits up completely with some scotchbrite and wet/dry.