Sciencemadness Discussion Board

Carbon Electrode Source

untuned - 9-10-2012 at 15:22

Found a cheap solution for a carbon electrode; a motor brush.

Hexavalent - 10-10-2012 at 07:15

Looking at the size, they don't seem that big.

Getting carbon electrodes from batteries is what I've always done, as I also get large quantities of MnO2 and zinc metal too.

untuned - 10-10-2012 at 07:22

I agree they are small. Batteries are a great source too. Probably better for a lot of things, plus you get the MnO2 and zinc.

The company has many different sizes, so I bet they have larger ones.

Might be good for a simple hoffman apparatus or similar demonstration experiment.

elementcollector1 - 10-10-2012 at 07:40

I personally don't like the carbon electrodes from batteries; they release resin into any non-neutral aqueous environment (basic and acidic), turning the solution an annoying yellow.

The MnO2 from batteries is terrifically impure with ammonium chloride, zinc chloride, and carbon in the form of sticky graphite.

The zinc is good, though.

The best source of a carbon electrode is a welding electrode. They're usually somewhere around $7, and they're HUGE.

Hexavalent - 10-10-2012 at 11:26

The battery electrodes are suffice for most electrolysis needs, despite this problem.

The dioxide can be purified by water washes - it still won't be great but for a lot of lab work, especially where it's purity is not especially important, such as, in this case, e.g. making chlorine, it will suffice.

Dave Angel - 10-10-2012 at 11:48

I've had a lot of success with 'carbon arc gouging rods' which may or may not be identical to the welding electrodes mentioned by our elementcollector (my knowledge of welding is limited). These really can't be beaten for price, and lack of hassle of preparation, plus they are built to take high current.

Those I have bought are nearly completely covered in a layer of copper, which readily peels away in a spiral all the way down the rod after being nicked with a sharp knife. This also leaves one with a bonus source of scrap copper ribbon...

smaerd - 10-10-2012 at 13:03

Ebaying for "Carbon rod", "Carbon welding rod", and "Carbon Electrode" are all fruitful.

hissingnoise - 10-10-2012 at 13:08

Two sellers here!

Dave Angel - 10-10-2012 at 13:18

Watch out for any that look too light a grey for graphite; they look a bit like sparklers, and appear to commonly come in widths up to 3.25 mm. I think they are flux coated metal rather than carbon from what research online I've done. Not got a hold of one yet so don't quote me, but the UK chain store Machine Mart is an option to handle these things in person - my next shopping trip to confirm...

m1tanker78 - 10-10-2012 at 13:36

Go to your local welding shop and look for gouging rods (as they're called here). I buy them by the box and will never look back at battery carbons. Mine are copper coated as well but as Dave said, the copper coating can be removed mechanically (or chemically).