Just wanted to roll back around to this point you made. I've watched a demonstration of a diffusion pump by Applied Science: https://www.youtube.com/watch?v=SrNVLCHrJtY&ab_channel=AppliedScience
Another video mentioned a diffusion pump not being a good suit in application where avoiding contamination is key and Nixie making seems like the sort of case scenario where contamination would cause failure in the nixie. I could however be wrong. Would this make diffusion pumps unsuitable as a starting point? On Friday, September 15, 2023 at 11:01:45 PM UTC-4 gregebert wrote: > I'm not an expert on vacuum systems, but the units I see most-commonly for > low vacuums (such as what you would see in a typical engine or vacuum > cleaner) are inches or mm of mercury; higher vacuums are measured in > microns. One Torr (1mm Hg) is 1000 microns. It's a tad silly, because you > cannot physically measure 1 micron of Hg in a manometer, though at room > temp the vapor pressure of mercury is quite low, around 2 microns. > > I'm guessing that nixie makers will use whatever high-vacuum equipment > they can find and afford, and from the brief video shots the setups look > like they use high-quality (expensive) equipment. Nothing looked cheap or > kludgy. > > You can even use atmospheric air at low pressure to get a gas discharge. > > On Friday, September 15, 2023 at 9:01:27 AM UTC-7 Miles Thatch wrote: > >> > supposedly can get down to 35 microns >> Is there a particular technical reason to not use the torr unit of >> measurement when discussing vacuum? Just curious if it's just personal >> choice or if there's a technical principal at play. >> >> > My plan is to do some heating/baking while the system is fully evacuated >> I have seen Dalibor do this in one of his videos. >> >> I've also seen it in this one as well at 10:24: >> https://www.youtube.com/watch?v=uHv1f4_tDv4 >> >> Also here, another nixie making gentleman: at 6:57 >> https://www.youtube.com/watch?v=MyhmEUw4OL0 >> >> > To do quality work, you will need another pump, typically a diffusion >> pump, which will get you below 1 micron >> I don't think I've yet seen any of the nixie makers talk about exactly >> the sort of hardware they use, Just glimpses in an occasional camera shot. >> Do you reckon it's what Dalibur and these other gents use? >> >> >> On Friday, September 15, 2023 at 11:27:49 AM UTC-4 gregebert wrote: >> >>> I bought an A/C evacuation pump from Harbor Freight Tools that >>> supposedly can get down to 35 microns; I dont have any equipment to measure >>> anywhere near that low. It was a relatively inexpensive pump, around 80 >>> USD. I think it's sufficient to do some experimenting. My plan is to do >>> some heating/baking while the system is fully evacuated, then pressurize >>> with enough argon (it's cheap and widely available) to get a glow. If I can >>> sustain the glow for several minutes while heating the tube, I will pump it >>> down a second time to hopefully get rid of any additional released >>> contaminants, then refill. After I've made a few of these, I'll make a >>> decision to continue spending time-and-money, or decide my experiment was >>> enough to satisfy my curiosity and move onto something else. I'm definitely >>> not going to build nixies. There are a few other things I want to make that >>> require a vacuum and some glasswork, such as a radiometer. >>> >>> To do quality work, you will need another pump, typically a diffusion >>> pump, which will get you below 1 micron and will be rather costly. The >>> mechanical pump must first be used to pump down as much as possible, before >>> the diffusion pump is used. >>> >>> On Thursday, September 14, 2023 at 9:24:05 PM UTC-7 Miles Thatch wrote: >>> >>>> Ok, that makes more sense. So in that case High Vacuum is required to >>>> evacuate then. >>>> >>>> What sort of pump would I need to be looking for to achieve that? >>>> >>>> On Thursday, September 14, 2023 at 5:41:36 PM UTC-4 gregebert wrote: >>>> >>>>> OK, that's once the tube is pressurized with the desired gas. However, >>>>> to cleanse the tube of impurities, it must be baked-out and evacuated to >>>>> a >>>>> rather high vacuum. Even at a high vacuum of 1 micron, there are still an >>>>> extraordinary number of gas molecules present, on the order of 10^16 per >>>>> liter. For home-made tubes I would actually want to re-evacuate the tube >>>>> a >>>>> second time, and refill, to get even more impurities removed. >>>>> On Thursday, September 14, 2023 at 10:28:06 AM UTC-7 Miles Thatch >>>>> wrote: >>>>> >>>>>> From he Drive books archive >>>>>> Nixe Tube Data > NixieGas.pdf >>>>>> >>>>>> I was using the following excerpt from this book. Is it wrong or am I >>>>>> getting something mixed up? >>>>>> >>>>>> On Thursday, September 14, 2023 at 11:43:46 AM UTC-4 gregebert wrote: >>>>>> >>>>>>> I think you mean 10-50 microns (which is 1000 timer lower), not >>>>>>> 10-50 Torr. One atmosphere of pressure is 760 Torr (760mm Hg). >>>>>>> I've seen neon-sign texts stating the need to get below 1 micron for >>>>>>> proper bombarding, and I imagine nixie tubes are similar. >>>>>>> >>>>>>> On Thursday, September 14, 2023 at 6:57:51 AM UTC-7 Nick wrote: >>>>>>> >>>>>>>> Look at Dalibor's videos. >>>>>>>> >>>>>>>> On Thursday, 14 September 2023 at 12:08:57 UTC+1 >>>>>>>> [email protected] wrote: >>>>>>>> >>>>>>>>> Good day. >>>>>>>>> >>>>>>>>> Since we require to reach vacuums of 10 - 50 torr depending on the >>>>>>>>> gas mixture. What sort of vacuum pumps are we looking at sourcing to >>>>>>>>> achieve those levels? >>>>>>>>> >>>>>>>> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion, visit https://groups.google.com/d/msgid/neonixie-l/49212b91-c353-4e5f-9f57-bf4722f1484en%40googlegroups.com.
