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 on the web, visit https://groups.google.com/d/msgid/neonixie-l/d2d43224-ce86-40f9-b493-afd49d39e254n%40googlegroups.com.
