View Full Version : Rust removal questions..
11-03-2004, 07:30 PM
Well, I just tried electrolysis for rust removal. Had an old saw blade that was really, really bad. I wasn't very impressed with my results - but I don't think it's working quite right. May be someone can give me a couple pointers.
I let it set in the tub for about 5-6 hrs with the charger on. I could tell there was some action taking place - but not very much. I'm not sure the charger is working right. The meter reads a trickle amount of amps even though I have it set on 10 amps. The guy at the hardware store says that all chargers these days requires it to be hooked up to a battery to work since it 'senses' the charge in the battery and automatically adjusts the output. Is this causing my result to be very slow/poor? Is there a way - or a chafger - that will give a 10 amp output?
11-04-2004, 07:57 AM
I don't think the guy at the auto place knew what he was talking about. Every battery charger I've ever had or used, when hooked up to a good battery that had a low charge would initially show a max flow (amps) dependent on the setting of the charger. As the battery approaches a full charge the ammeter on the charger would show less and less flow.
What you've got is probably excess resistance in your system. My best guess would be that your anode is too small, has a buildup of semi conducting crud, a bad connection at the anode or the saw blade, or the piece being derusted is too far from the anode. In my experience it has been crudded up anode or a bad connection. When you plug the charger in set at 6 or 10 or whatever amps, you should be getting a reading pretty close to that on the meter.
BTW, for saw blades you want something around 2 amps or so as the higher flow can cause hydrogen hardening of the blade. This can be remedied, but . . .
I've quit using 'lectricity to remove rust from saw blades. I've found that 320 grit sandpaper and vinegar make quicker work of it than bombarding the thing with free electrons.
11-04-2004, 08:02 AM
* Was the blade suspended in the tub or laying on the bottom. Works best suspended
* Did you have several positive electrodes connected together? I use a grid of rebar connected (above water) with copper wire. Having electrodes partially surround the item is better.
* What did you use for an electrolyte? I use about 1/2 cup of washing soda for about 4-5 gallons of water. More if I'm feeling frisky.
I use a schumacher battery charger I think. Bought it in a pawn shop. I think I know what you're referring to with the auto-sensing of the battery. Maybe your charger is doing that, maybe not. If it has some kind of manual mode you could try that. Mine has Normal and Deep Storage and I can't tell the difference between either.
It does sound a bit like you don't have enough electrolyte in the solution or that possibly you're not making good contact between the leads and the blade.
11-04-2004, 10:02 AM
As an alternative you might want to try a bath of citric acid.
this doesn,t require an electric charge and a good soak is equally effective at removing rust although it will not convert it to the non rusting iron compound that electrolysis provides. So a quick zap with the electrolytic tank after is recommended or a wipe with phosphoric acid (gun blue).
It does remove the loose rust much quicker.
Although citric acid is present in lemon juice etc the concentrated stuff in crystal form is like "lemon juice" on steroids so wear gloves and eye protecyion if you go this route.
Electrolysis only converts the rust and doesn't replace the metal so what you may be seeing is a badly pitted surface which is now black rather than orange.
11-04-2004, 10:11 AM
I am not sure what active ingredient Naval Jelly has but it sure helps take those rust away. IMHO it is worth a try.
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