When you use the salt does it leave any nasties in the water when you are finished ?
Hate to have the HazMat guys around asking questions !
When you use the salt does it leave any nasties in the water when you are finished ?
Hate to have the HazMat guys around asking questions !
In reply to californiamilleghia :
I hope not, I dumped mine down the sink when it was over.
There was a note earlier from Nohome about being careful with stainless steel because you can generate hexavalent chromium, so it might be worth investigating alloys.
It's been a long time since high school chemistry, what can you make with water, salt and aluminum? Or brass?
So I tried with a good battery. It seemed like nothing was happening for a solid two hours. I mean stuff was happening, but very very slowly.
I decided to leave it for a while, came back to find this:
Not sure what happened, but somehow it accelerated dramatically. My test part looks like this now: (those etched areas are very deep)
So I believe what happened is there must have been a light coating on the cathode last night. As that wore away, the etching accelerated. Today I made a few changes, but I used that same piece, and the instant I put it in the tank and connected the wires, lots of bubbling/activity began to take place.
Attempt #2:
Annnd.... cathode failure (there was a hole through the part and a wire wrapped around it)
Now I'm wondering if I do a proper connection. Drill and tap the part, attach wire with a ring terminal, then seal it with silicone, preventing it from basically etching itself away.
Attempt 2.1:
In reply to ProDarwin :
That looks really cool. 
No kidding. I want to know more about the design.
Remember that aluminum forms a layer of oxide, that should be cleaned off first. Perhaps that’s what you burned through. Scotchbriting the piece before it goes in the tank will help
For an electrical connection, I’ve been able to successfully fan the wire out and just tape it to the clean surface. If you get a water leak, it’ll corrode. I’ve never run anything as deep as you have.
Keith Tanner said:No kidding. I want to know more about the design.
Its smith mountain lake. I've been going there since I was a kid. My parents retired there ~5 years ago. I making a piece of 'art' for my mom.
I was able to use Google Map Customizer to tinker with the CSS and basically show only water and land with in 2 flat colors. Then I did a little cleanup in photo software - removed the smaller waterways and some of the small islands. I set the resolution to something crazy like 5k x 5x and then used a scrolling-screencap plugin to take the screenshot (it takes a ton and splices them all) so I didn't lose the small details. I probably went overkill, but originally I was thinking of doing a piece up to 24" square, so a typical browser screenshot wouldn't cut it.
I have some text to add as well as a compass on the final piece.
That’s not “art”, it’s art. Can’t wait to see the end result.
Cutting the final vinyl now, will try the etching with steel this afternoon.
Keith, could you provide a little more detail on the iron-on method you used on page 1 that allows for the use of a gradient? What specific paper did you use? Is that achievable in a standard inkjet printer?
For the steel cathode I drilled through and used a nut+bolt to clamp the wire. Then I caulked around it to minimize any leak.
(The caulked part will be submerged in the future)
I ran a test but the anode had too much scale on it. The actual part I wanted to etch doesn't have scale so I'm not too worried about it. This goes in the tank tonight:
The dots at the corners are to prevent it from etching where the standoffs will be attached to mount it when complete.
That's very cool. Smith Mountain Lake is gorgeous. There's a wonderful wooden boat show there every year.
Small update:
Etching is done. I made the mistake of removing the mask early though.
Unlike aluminum, when steel is etched it doesn't provide a good contrast between the etched and un-etched surfaces :( If I left the mask on I could allow the etched areas to rust a bunch. But I didn't. Now my hope is to let all of it rust and then sand/polish down the raised areas, which will be quite difficult.
(This pic shows the best case contrast. If you look straight on its much harder to see)
So another update. I took the above piece and decided to let it rust a bit, then block sand down the top layer to get the contrast back. This did not work for 2 reasons:
1) the etching depth was not consistent. Near the center of the plate it was too easy to accidentally sand the etched areas instead of just the lake design.
2) The rust pitted the un-etched areas too much so I couldn't really sand it down enough to get the smooth metallic finish back. Oops.
Time for attempt # ??
This time I used the plate above as the anode for a new plate I was going to etch. To make sure the etching was consent, I held them offset from one another a fixed amount:
This worked really well except it draws ALL OF THE AMPS!. I really need to hook up a real 12v power supply so I can regulate the amperage. The etching only took a few minutes... the same amount of time it took to literally melt the wires running to it (oops) and totally drain the battery (oops).
This time I left the masking in place, painted it black, removed the masking (with trouble removing adhesive) then cleared it. The adhesive removal step was fairly abusive and involved a torch. (oops). But it got it done, and although it didn't come out how I wanted, it still looks cool, has some character, and my mom loves it.
In reply to ProDarwin :
Very cool!
In reply to Keith Tanner :
Thank you Keith I have be playing around with metal etching for about a month. Tried several things. 9 volt battery and q-tips, phone charger, I even took apart a power supply from one of my old desktop computers. Never was enough power and also very time consuming. They worked but not for the scale that you and I are trying to do. Below are my videos.
I did another etch with Marvel Comic characters for my friends children. And that came out pretty good.
BTW. Get a Cricut machine. You can do your own stencils with vinyl sheets that have adhesive. Then you can play to your hearts content making them. Unfortunately they don't sell them in masculine colors. LOL
Bummer. I guess the links don't work. oh well. Here are some screenshots. Battery from Walmart 60 bucks
A vigorous response. :)
Nice! The Cricut is the hobby version of the vinyl cutter I was using. Probably a lot easier to find on Craigslist and certainly easier to find at a hobby shop. You can always rattle can it black with flames or something.
Now that I have a couple of laser engravers, I should pick this up again. The lasers can't engrave metal but they're great at removing paint. So I hose down the piece with paint, burn off the design with the laser and then etch it with the battery. I have some ferric chloride in the shop now as well but haven't taken the time to play with it.
I worked in a copper electro refining tank house for a while which is a very similar concept - dissolve the 99.8% copper anode and it plates out as 99.9999% copper cathode sheets. I used to mask off sections of a small extra cathode I'd hang in the end of the cell and plate different designs in thin sheets of copper.
If the cathode is too close to the anode, current will preferentially flow through the closest sections of the electrodes, so that explains why some sections might get deeper than others. They should be parallel if close to each other, increasing the distance with reduce this effect but the resistance in the circuit increases so the current efficiency increases and hence speed of the prices is reduced.
The localised issues caused by a high concentration of aluminium in the solution are indeed solved by circulation. If the electrolyte flow is too low, the quality of copper plate deteriorates due to the same effect - localised starvation of copper in the electrolyte causes porous metal playing to occur. It's a good idea to circulate the electrolyte with a small pump or some sort of stirrer.
Very cool, this has given me ideas!
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