Junk_Enginerd - 17-9-2021 at 00:29
I'd really like to acquire some Neon. I enjoy doing experiments with discharge lamps etc, and I have tried quite a few elements and substances, but
nothing seems to be quite as unique as Neon in this context. Argon shares some of its qualities but it's got basically the same familiar emission
color as ordinary air.
I've found a few sources of Neon, but it's all industrial sized. A 10 L 70 Bar bottle would last me 50 lifetimes lol, and it's prohibitively
expensive. Considering the super tiny amount I'd need in a discharge lamp(probably <1 ml+a little waste), it's ridiculous to buy such a large
amount.
There's also plenty of neon ampoules to buy, but those are already low pressure so I wouldn't be able to use it for anything...
Is anyone here aware of a source where a reasonably priced/sized canister of Neon can be bought? Wasn't Neon sign making an amateur hobby in at least
some extent at some point? Feels like it should exist, but my google fu fails me and I find nothing.
[Edited on 17-9-2021 by Junk_Enginerd]
fredsci93 - 17-9-2021 at 01:11
Lot's of places sell disposable cylinders, around $100 for 10 liters (https://www.ebay.com/itm/312653878000?hash=item48cb9f92f0:g:...)
(this one is Neon/argon but you get the idea)
I think you could find a smaller one if you look hard enough, but I haven’t looked much
[Edited on 17-9-2021 by fredsci93]
Edit by admin: disabled smilies
[Edited on 9-18-2021 by Texium]
Junk_Enginerd - 17-9-2021 at 01:25
Haha, what you linked is the exact single one I found too. That's... not a lot of places.
I don't think Ar/Ne mix is a bad thing for my purposes. Afaik it's mixed with argon to give it better properties in for example discharge lamps, so
it's really quite ideal.
I was hoping to find other sources in addition to this one, hopefully something cheaper and also not so expensive shipping.
numos - 17-9-2021 at 22:13
Have bought from these guys before:
http://prosites-llcwccd.homestead.com/NEON-GAS.html
It's 2.25 L of gas at 1 atm. You mostly need low pressures (I think 15-30 torr) for discharge tubes, so 2.25 L will make hundreds of tubes. You do
need an apparatus to measure and add gas to your tubes.
Edit I see that you said you can't use low pressure ampules... In that case good luck. Almost all neon suppliers will sell small amounts in ampules
for making discharge tubes. Larger amounts for research purposes will be in cylinders of >10 L. As far as what I've seen, the product you are
looking for doesn't exist. You may have to bite the bullet and buy a lecture bottle for $600 =(
The upside of having a larger amount is that you may be able to fill at higher pressure (400-800 torr). This will allow you to make plasma tubes as
well!
[Edited on 9-18-2021 by numos]
Junk_Enginerd - 17-9-2021 at 23:45
Cool, thanks. By low pressure ampoules I meant ampoules that are basically for element collectors, and already at the 15-30 torr range. I guess
they're not really meant to be used other than excited to study emission spectrum. 1 atm at 2.25 L should be just fine!
Would you mind explaining the difference between a plasma tube and a discharge tube for this layman?
numos - 18-9-2021 at 23:08
Discharge tubes are any gas filled tubes that emit light when excited, this is the most general category.
Low (10-20 torr) pressures of gas emit a diffuse light: neon lights, fluorescent lights, shortwave UV tubes all fall into this category.
Here is a frankenstein neon tube I made a few years back. It has a neon/mercury gas mixture, with several glass tubes sealed together. You can see the
red emission of neon near the electrodes, the nice blue color on the right is the mercury emission (UV is blocked by the glass), then the purple and
green colors are due to phosphors excited by the UV light emitted by the mercury.
Higher pressure plasma tubes have anywhere from 100-760 torr pressure with any of the noble gases, N2, H2, mixtures thereof, I've even seen some
people add SF6. These are usually more artistic, and by varying the voltage and frequency you can get some surprising effects.
A buddy of mine at Berkeley used to make plasma tubes, you can visit his site for an idea of this looks like. Although plasma is an expensive hobby, be prepared to drop $5K to get started... Something for me to look
forward to when I'm done with my studies 
Junk_Enginerd - 20-9-2021 at 01:44
Oh my fucking god you basically made my brain nerdgasm with that link, that's exactly the type of stuff I'd love to make.
I guess I usually end up more in the plasma lamp territory, sometimes because I'm having issues with a high enough vacuum, and sometimes just because
it looks more interesting. The 10-20 torr range is where the pump I have starts to reach its limit. You can always go a little bit lower, but
it takes more and more tricks to get further.
What's the pricey parts? I can basically make those lamps with stuff I've got laying around, except crappier, smaller and uglier lol.
[Edited on 20-9-2021 by Junk_Enginerd]