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You may recall my garden ornament, Snappy.
It's supposed to be rusty, but I discovered the bottom of the stem, where it sticks in the ground, was rusting very quickly. I wanted to put some zinc on it, because zinc prevents rust. I'm not sure of the science - something about electron flow - but zinc can really prevent rust. You find zinc plating on most screws and bolts, and it's used on rust prevention for cars. I figured I could just heat up some zinc with a torch and drip it on there, but then I learned about electroplating, and it didn't seem too tough.
First I needed to get the rust off. I found out how to do this while taking care of my cast iron pans. You use a bucket of water with sodium carbonate (washing soda) in it, to make the water more conductive. You put metal in the bucket (this is the anode) and hook it up to the positive lead on a battery charger. Then you hang the part (the cathode) in the water and hook it up to the negative lead.
Most battery chargers put out either six or twelve volts. You'll probably need twelve unless it's a small part. They say it should only take a couple of hours even if there's a lot of rust, but it took a lot longer than that, for my parts. If you try to attach the clips where there's rust, the current can't get through, so you have to sand the rust off there. Electrolysis really only takes rust off the surface, so you have to remove the loose rust. Fortunately, the process helps loosen the rust. Unfortunately, you still have to remove it yourself. Also, the process is "line of sight" so rust only comes off of places that have a direct line to an anode.
Electrolysis produces hydrogen and oxygen (that's what's bubbling out of the water), so you want to do this outside. I did it in my shed where there was a breeze. It did worry me a bit, when I didn't have a good connection, and the clips were sparking. If you were to put salt in the water, instead of sodium carbonate, it would produce chlorine instead of hydrogen. I'll take flammable over toxic, thank you.
Then I applied the zinc with electroplating.
I started with a bucket of vinegar. Not sure why we use acid - to help dissolve the zinc? We put magnesium sulfate in (epsom salts) to make it conductive, and sugar to inhibit crystal formation in the zinc (for a smooth surface). I put in zinc anodes (connected to the positive leads) and again, the part was my cathode (connected to the negative lead). My power source was two D-cell batteries, for three volts and some small amount of milliamperage. The vinegar is only 5% acid, but the zinc pieces bubble while in it. I drilled holes in the zinc anodes so I could connect the wires easily, and I put the shavings in the vinegar. It's the dissolved zinc that is applied to the cathode, so in addition to letting the zinc dissolve overnight, I put power on the anodes for a short time. The solution is then called zinc acetate.
The plating process is a bit deceptive. I seems like it's hardly doing anything, but over time the zinc really does build up. One thing I didn't do was agitate the solution. It looks like most people put an aquarium pump in it. I didn't even stir it. I also didn't wash the part in muriatic acid first, to get all the oil and contaminates off, but then it went pretty much straight from one bath to the other. I took the part out of the zinc every so often and wiped it down, checking the progress. I forget how long it was in there. Over two hours. Here's what it looked like:
Zinc is a bit soft, and I didn't do any treatment to it to harden it up, so we'll see what happens over time. It was a bit expensive. The zinc was $25, with shipping. Six bucks for steel (I couldn't find anything of an appropriate size that I wanted to sacrifice). I used two tablespoons out of a whole $8 box of washing soda, and the vinegar was what, three bucks? The power sources, wires, blue tape and buckets were lying around. But if I ever do it again, it will be free, unless I need to buy more vinegar. But I still have the zinc solution at the moment.
I tried a second part - a cast iron floor drain from my basement. I got a handful of rust off of it. I electrolysised it for a few hours, and still have a little bit left to go. I'm not sure how it will plate, but I'll try it just to see what happens.
.
It's supposed to be rusty, but I discovered the bottom of the stem, where it sticks in the ground, was rusting very quickly. I wanted to put some zinc on it, because zinc prevents rust. I'm not sure of the science - something about electron flow - but zinc can really prevent rust. You find zinc plating on most screws and bolts, and it's used on rust prevention for cars. I figured I could just heat up some zinc with a torch and drip it on there, but then I learned about electroplating, and it didn't seem too tough.
First I needed to get the rust off. I found out how to do this while taking care of my cast iron pans. You use a bucket of water with sodium carbonate (washing soda) in it, to make the water more conductive. You put metal in the bucket (this is the anode) and hook it up to the positive lead on a battery charger. Then you hang the part (the cathode) in the water and hook it up to the negative lead.
Most battery chargers put out either six or twelve volts. You'll probably need twelve unless it's a small part. They say it should only take a couple of hours even if there's a lot of rust, but it took a lot longer than that, for my parts. If you try to attach the clips where there's rust, the current can't get through, so you have to sand the rust off there. Electrolysis really only takes rust off the surface, so you have to remove the loose rust. Fortunately, the process helps loosen the rust. Unfortunately, you still have to remove it yourself. Also, the process is "line of sight" so rust only comes off of places that have a direct line to an anode.
Electrolysis produces hydrogen and oxygen (that's what's bubbling out of the water), so you want to do this outside. I did it in my shed where there was a breeze. It did worry me a bit, when I didn't have a good connection, and the clips were sparking. If you were to put salt in the water, instead of sodium carbonate, it would produce chlorine instead of hydrogen. I'll take flammable over toxic, thank you.
Then I applied the zinc with electroplating.
I started with a bucket of vinegar. Not sure why we use acid - to help dissolve the zinc? We put magnesium sulfate in (epsom salts) to make it conductive, and sugar to inhibit crystal formation in the zinc (for a smooth surface). I put in zinc anodes (connected to the positive leads) and again, the part was my cathode (connected to the negative lead). My power source was two D-cell batteries, for three volts and some small amount of milliamperage. The vinegar is only 5% acid, but the zinc pieces bubble while in it. I drilled holes in the zinc anodes so I could connect the wires easily, and I put the shavings in the vinegar. It's the dissolved zinc that is applied to the cathode, so in addition to letting the zinc dissolve overnight, I put power on the anodes for a short time. The solution is then called zinc acetate.
The plating process is a bit deceptive. I seems like it's hardly doing anything, but over time the zinc really does build up. One thing I didn't do was agitate the solution. It looks like most people put an aquarium pump in it. I didn't even stir it. I also didn't wash the part in muriatic acid first, to get all the oil and contaminates off, but then it went pretty much straight from one bath to the other. I took the part out of the zinc every so often and wiped it down, checking the progress. I forget how long it was in there. Over two hours. Here's what it looked like:
Zinc is a bit soft, and I didn't do any treatment to it to harden it up, so we'll see what happens over time. It was a bit expensive. The zinc was $25, with shipping. Six bucks for steel (I couldn't find anything of an appropriate size that I wanted to sacrifice). I used two tablespoons out of a whole $8 box of washing soda, and the vinegar was what, three bucks? The power sources, wires, blue tape and buckets were lying around. But if I ever do it again, it will be free, unless I need to buy more vinegar. But I still have the zinc solution at the moment.
I tried a second part - a cast iron floor drain from my basement. I got a handful of rust off of it. I electrolysised it for a few hours, and still have a little bit left to go. I'm not sure how it will plate, but I'll try it just to see what happens.
.
no subject
Date: 2020-09-08 12:39 am (UTC)From:no subject
Date: 2020-09-08 12:50 am (UTC)From:It's probably been a while since pics of him have shown up.