…Is Argon plasma white.
Finally! The KF-16 coupling arrived and I could test the vacuum chamber again! But first, some build pics:
Drillset. 7-10-13-15-16mm and then the boring head up to 19mm
Finishing the hole. It’s an interesting device, I must say. Bought it years ago, and never used it (but knew someday it would come in handy).
TIG welded and began assembling the vacuum lines.
Crudely put everything together.
Quickly reached 160 microns and drove up the voltage…but past 1000V no plasma was to be seen. I verified connections in case a cable was loose (highly doubted that, but one must check everything). and finally, tried increasing Ar pressure to 1000/1200 microns, wich obviously arced. Then decreased the vacuum again…and had to go waaay up (voltage wise) than before (with the cheap pump) to get some plasma glow.
With my cheap multimeter maxed out, an arc current spike fried it out, so I don’t really know what voltage this thing required to light up at 160/140 microns. All I can say is that my guesstimate on the cheap pump’s ultimate vacuum was probably waay out, more in the range of 500/800 microns (can’t know for sure).
In the end it was very late and had to stop the pump, so I left it unvented as a test for the integrity of the whole vacuum circuit.
Yup! I forgot this pump doesn’t have a non-return valve, so the oil was sucked up the circuit. The whole vacuum chamber was soaked in oil when I arrived from walking the dogs, it must have went up quite far, however, the rest of the circuit hoses apear to be clean, so I guess it bubbled up in the chamber. Well, this is not worse than having a blow-by with an oil difussion pump. Luckily I already bought a vacuum valve, so this shouldn’t happen again. ^^U
Anyhow, this morning i decided to try some sputtering (yes, without cleaning the oil mess…it was just a quick and dirty test).
This was in the adhesive side of a smartwatch glass screen protector, so the copper crackeled, hence the small test point and it was retired from the chamber after a few minutes, so the copper thickness was small.
Also accidentally deposited copper in the centering seals XD!
Anyways it’s definitely good copper. Aplied some Sn/Pb solder with the soldering iron and it wetted perfectly:
Now, yes, I’m surely cleaning the vacuum circuit from all the oil. XD