Need some help building or buying a very high voltage power source.

[RayRay1132]

I've recently been learning how to make neon tubes and my vacuum pump cant get a good enough vacuum to make the tubes work continuously, even with adding mercury to lower the striking and running voltage. I've tried multiple different ways to make the tube light including an old fashioned and a new neon transformer. The old one will only blink the tube once and a while while the new one will make it flash for a second when it tries to strike the tube but then quits. I've used a tazer module from eBay to make the tube work but the problem is that they cant be run continuously and burn out after 5 minutes or so. Can someone point me towards a very high voltage(>15KV neon sign transformer (do these exist??) ), or give me an idea on a decent circuit to light my tube.

Thanks in advance -Ray, KD2JID

 

[rjenkinsgb]

Hi Ray,
if you have learned to blow and form glass, you could make a diffusion pump that will give seriously good vacuum over a few hours.

This is a DIY setup from a 1960s book I have (a collection of 50s Scientific American projects), suitable for getting down to valve/electron tube type levels:



[It finishes with warnings of the possibly implosion hazards when using large glass containers as vacuum reservoirs and that the must be enclosed for safety, and not rapidly allowing air back in as can hammer the mercury or diffusion oil against the inside of the glass and break it, plus mercury hazards etc.]

 

[RayRay1132]

Hi Ray,
if you have learned to blow and form glass, you could make a diffusion pump that will give seriously good vacuum over a few hours.

This is a DIY setup from a 1960s book I have (a collection of 50s Scientific American projects), suitable for getting down to valve/electron tube type levels:

View attachment 132026 View attachment 132027 View attachment 132028

[It finishes with warnings of the possibly implosion hazards when using large glass containers as vacuum reservoirs and that the must be enclosed for safety, and not rapidly allowing air back in as can hammer the mercury or diffusion oil against the inside of the glass and break it, plus mercury hazards etc.]

This is great thanks for finding this article, I've been using an old ac compressor a a vacuum pump.

 

[rjenkinsgb]

You probably need a better main vacuum pump as well then; the article says most AC compressors cannot pull a really good vacuum due to the type of valves used.
You can get pretty decent ones sold for air conditioning use at reasonable prices - AC & refrigeration systems need vacuuming to remove all air and water vapour before the refrigerant gas is introduced.

eg. First one I found on ebay.

3CFM 1 Stage Refrigerant Vacuum Pump Refrigeration Air Condition 1/4 HP HVAC | eBay

Find many great new & used options and get the best deals for 3CFM 1 Stage Refrigerant Vacuum Pump Refrigeration Air Condition 1/4 HP HVAC at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

 

[whit3rd]

The usual appliance to make a glow, is a Tesla coil (buzzer-type, in handheld form) like
[commercially available Tesla coil ] or one can put the object of interest through
a brief visit to the kitchen microwave (with a cup of water alongside). The best results from a
neon lamp (lowest threshold of conduction) require a bit of helium added to the mix; not
much, but the strike voltage goes down with that gas mix.

I've heard that commercial neon sources are good for welding, but not extremely pure; some
extra refinement of the gas may be required if a discharge lamp is to be successful.

 

[schmitt trigger]

I also have heard the same, for glow lamps the neon should be purified further from the commercial variety.