uncoated carbon arc gouging electrodes - the EDR test

Well, my test electrode has been bubbling nicely in solution for over 24 hours now, and shows no sign whatever of having the binder dissolve or anything. Also, I haven't noticed any dropoff in current from "anode loading" i.e. from the anode becoming more resistive over time. So, early tests are looking good.

Another thing I like about these (3/8x12") carbon electrodes is that the alligator clips on my little battery charger fit the carbon electrodes very well. Most car battery terminals are close to being cylindrical slugs of lead, and so the charger leads are designed to clamp nicely to a round shape. They work very well.

If this works OK for another day I'm going to declare success and buy a few more of these and try drilling and tapping No. 10 holes on one end for brass screws. I have lots of crimp-on fittings, and if I wanted to have several anodes in parallel around the periphery of a container (as I often do to achieve a more uniform field i.e. "line of sight") this would make it a simple way to effect positive connectivity between wire and carbon.

I'm happy about this so far.

GWE

Reply to
Grant Erwin
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OK, what I'd feared has started to come to pass. After about 36 hours working in the solution, the bath turned black and the electrode has started to get eaten away. Originally a tad over .375", it's now down to about .310" at its thinnest. So using these for EDR electrodes, while they work, does turn the bath black (messy!) and also the electrodes get consumed slowly.

The amperage never dropped, though, like my steel electrodes' did.

I'm done testing. My conclusion is that *this* batch of uncoated arc gouging electrodes doesn't hold up to steady use in electrolytic derusting. I still think it may be possible that similar electrodes from another manufacturer might hold up better.

GWE

Grant Erw> Well, my test electrode has been bubbling nicely in solution for over 24

Reply to
Grant Erwin

You might try reducing current density (lower voltage/more rods) or impregnating the rods with linseed oil. I guess you'll want to wait until the wife is gone to bake them..

Tim

Reply to
Tim Williams

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