Rob (aka the mad plater),
Those spark plug connectors turned out really nicely! And your plating bucket looks pretty much like mine but it might be a good idea to call those zinc strips the anodes (they're connected to positive DC) lest we start confusing ourselves and other readers. In electroplating, the anode is the supply of plating metal, and the cathode is the part being plated. At any rate, time for new zinc!
Wilf
For the home plating specialistWilf,
I have zero experience with plating. I know that the cathode is the positive terminal on a battery and is the terminal from which electricity leaves a cell. The anode is the return terminal or negative. Since the current is flowing from the zinc to the part, I assumed that the zinc was the cathode (also remembered that the zincs on boats are for cathodic protection) based on that. But you know, when I think about it, the zincs used on boats are called zinc anodes. So the cathode is what is being protected versus being the protector. Your post made me look up Cathode in the dictionary. It confirmed my understanding. But that was all based on battery or voltage sources. There was a another definition that said it is the negative terminal in an electron or electrolytic cell, which I believe is what we have here with the plating bath. So I went a step further and googled electroplating circuit and it confirmed that for plating, the work is the cathode and the plating material is the anode. Getting back to boats, the ocean is the electrolyte so the zinc again, is the anode. Taking this back to a battery, the current in a battery flows out of the positive terminal. But inside the battery the electron are flowing from the plates to the positive terminal for this to happen, so inside the battery, the positive terminal is really the negative side of an electrolytic solution, which again makes it the cathode. Now the two conflicting definitions make sense. Never thought much about this. I'm a nuts and bolts kinda guy. Thanks for setting me straight. And I have to say that you did it in the nicest and most gentlemanly way. I'm going to try a circular anode for the next set up. Something that surrounds the periphery of the pail and then another sheet lying on the bottom connected to the circular sheet. Will be easier to make, easier to connect and easier to maintain/replace when the time comes. Guess I should go back and edit all my bass-ackwards posts. regards, Rob
Hi,
From a physics point of view the electrons flow from negative to positive in a conductor, not from positive to negative. The conventional current is from positive to negative. Now nobody understands anymore I guess. Positive is anode, negative is cathode, but in a galvanic cell, the cathode is positive and the anode is negative. I posted this to make things more clear ?????? Jensen assembly of Japanese motorcycles requires great peace of mind (Pirsig)
Rob, Jensen,
There are indeed 2 ways to view the flow of current, depending on which end of the wire you're looking at. When I was a kid in school we were taught that current flows from the positive battery terminal to the negative. Later I learned about current flow as a flow of electrons (as opposed to 'holes') which go from negative to positive. Both views are correct. The tricky part is in making sure we're all looking at the 'same end of the wire' when we talk about it and that's why I suggested we use the conventional anode/cathode labels used in electroplating--just to avoid confusion among ourselves and others. I think zinc ions have a positive charge, and because they are flowing to the part being plated, electrons from the part are flowing back to the anode (negative to positive). Wilf And this is why I'm a flange head and not an EE or physicist.
Getting back to basics, the finish on my parts has changed since I started plating. It went from very smooth and shiny to frosted and somewhat lumpy. Lumpy at a very tiny level. On the vintage Triumph forum, where I shared this process earlier this week, one of the members posted the zinc plating instructions from the Eastwood kit. It says a rough finish is due to over-plating, which is too much time in the bath. (Personally, I get pruney from too much time in the bath, but that's a topic for another discussion). My guess here is my bath was pretty much zinc free at first and hence 20 minutes put on a lesser amount of plating than my zinc laden bath a few days later. So paying attention to the time is key here depending on the age of your bath. This bears out Wilf's initial recommendations of parts taking between 5 and 20 minutes. He said he always leaves a new bath sit overnight with the zinc in the bath to get some zinc ions into the solution before plating. For now, my frosted parts are fine for me. Sure beats gray, partially plated and rust prone parts. When I do future parts, I'll be a little more anal about the time in the bath. I need to visit the Caswell plating site to see what they have regarding plating tips and techniques. My guess is there is still a lot to learn here. regards, Rob Rob,
I have noticed similar lumpy or grainy results at times. When I looked at your most recent pics I wasn't sure if I was seeing that effect or the result of your bead blasting. I have no experience with sand/bead blasting so I couldn't offer a useful comment. For the record, I wish I were a flange head, an EE and a physicist, but I have no expertise in any of the above (I'm not quite sure what a flange head is, but I'm guessing the term refers to someone with a skill set I don't have). I think your remark about "over-plating" is significant and that's why I often plate lightly, scrub and re-plate, and then do it all again. I wish I had my plating bucket all set up so that I could do trials in response to your questions/observations, but I've run out of parts to plate. Keep plating, keep posting--we will all learn. Wilf
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