• chironexchironex February 16
    So I've talked about magnetrons on here a few times. They're a vacuum device that allows you to coat something i a thin layer of metal or ceramic even if that thing can't be plated onto. Things like glass, bugs and magnets. Spent the past few weeks working with @thephakt to help her build one of her own so she can experiment with it. We'll be turning all our progress into a video at some point but we had some success and I felt like sharing. 

    Here's the device after being pumped down for the first time and the high voltage applied:


    And here's it with the manget in place:


    We're controlling it with a scariac that we built:


    And we made the chamber ourselves:


    Will keep ya'll updated on progress and if we get success coating things in metal.
  • JardiJardi February 22
    [I'm not sure your knowledge in the field, so please don't be insulted if i tell you something you already know!]
    This is really great to see! Just from the looks of it, the first thing that comes to mind though is: Do you know how deep a vacuum you are accomplishing? I know it's first light (which probably had you jumping up and down like a schoolgirl if you're anything like me) but it looks like you'll probably need a much deeper vacuum. Check over some seals, and perhaps get a deeper vacuum. I'd suggest a Welch 1400 or 1402 (I have some experience with electron deposition, but mostly Farnsworth Fusors).
    Also, you might want a greater voltage source as well... not sure a MOT at ~5000v will have enough energy for coating. I believe you need upwards 60,000v, but now 100% sure.
    Applied science has some excellent videos on sputtering/electron deposition. Perhaps you can get some ideas from him?  

    My first fusor i did something similar to you, where i drilled the smallest hole possible into a bell jar (trying to compromise the integrity as little as possible, and avoid as much leakage as i can), and stuck steel wire into it for the cathode. Drilling into the top and press fitting a brass nipple and cap (cap was on the inside, and had a hole drilled into it) gave a decent seal, possibly down to 200 microns.


    clay did a fair job of sealing it temporarily to change the shape of the inner cathode. 

    At my university, me and a friend will soon be attempting a plasma jet in standard atmospheric conditions with *probably compressed argon (or other gas) through a borosilicate tube.... Once we are successful, I will at a  point be attempting with a TiN metal as the cathode, to see if we can "cool coat" without the vacuum... Doubtful, possibly inefficient, and perhaps will give an imperfect coating, but the proof of concept alone would be great for advancement and for others to branch off creating another mechanical device capable of our goal.

    I'd like to be a part of this for idea exchange, and perhaps testing as well. 
  • ThomasEgiThomasEgi February 22
    I'm a little bit new on magnetrons and the processes involved here. But at the mention of voltages around 60kV, electrons speeding around in vacuum and crashing into metals my alarm bells start ringing a bit because you may accidentally build an xray generator and expose yourself to ionizing radiation.
  • chironexchironex February 23
    We've got a pretty nice vacuum gauge on it to measure the vacuum. The lowest we hit was 600mtorr. We're using an edwards 5 vacuum pump. We're chasing leaks and getting it lower and lower. Should hit 400-500mtorr at hopefully by end of day since we almost did before it blew another leak and we know where the leak is. Will still need to get it down to about 100mtorr though for it to really be working well. I think that voltage is waaaaaay too high. I've seen tons of videos of this and most people just use a MOT. We've got a 10000v transformer but it's really low current. May try that but I doubt it'll help. We also have a nice geiger counter so if we do increase the voltage that high, we'll be checking to make sure we're not irradiating ourselves. I think one of the next things we'll try is rearranging our highvoltage system to use a different ballast and just hit it with full power. The scariac seems to really keep the voltage down which is killer with our slightly too high pressure.
    We rebuilt the chamber which you can see in the latest image here:

    You'll notice the little wire is gone and replaced with a spark plug. 
  • chironexchironex February 25
    Well we found one of the major leaks after rebuilding the whole thing like 3 times. Got the pressure down to 145mtorr. Loaded in a piece of glass and it got coated in the thinest layer of metal. Just need to either do more cycles, or get the pressure a little lower. We're gonna add some vaccum grease to 2 seals to help them a little bit. Should help us get down to under 100

  • Any update on this? I follow your instagram - you do some really awesome stuff! 
  • Not lately. We're in the process of getting our new makerspace set up so that's taken priority. Once we are totally set up and can get our hands on a vacuum pump building another magnetron is top priority. I've been looking into different configurations and way of exciting the plasma. Next time I'm gonna go with RF instead of DC as it should work better. Also there's a place near here where I can get silver for cheap so I'll be able to use it as a target which will be cool