Neon Manufacture

The process of manufacturing neon lights is a very interesting subject and one which can be found on the world wide web at various sites specializing in this task.   Vacuum pumps such as those made at HyVac are often used to produce a vacuum which is the starting point in making a neon sign or lamp.  If a "high" vacuum is not achieved the neon will not light or the light will blacken on the ends after a short period of time.  Usually within the "warrantee time" forcing the producer to replace, or repair the light.  This is costly and exasperating.  there is some information on this web site that should be reviewed if you are having trouble in this application.  The first most basic suggestion I can make is for the neon producer to purchase a decent vacuum gauge.  Generally a thermocouple type vacuum gauge is desired.  If you are having a problem this is a invaluable tool for troubleshooting your system.  The cost in time saved at a given point in time will reward you with faster results.  If neon is your business, you should have a good gauge you can depend on.  The gauge enables you to do numerous things including making sure the units are totally pumped down as far as the baseline of your system will allow.  They can be employed on a production basis for this assuring a specific level of quality control.  They can also be used to troubleshoot a problem system. 

Many times we get calls from users in the neon field and they do not have a gauge.   We can offer suggestions but without the knowledge of where you are pressure wise to a specific number, it gets tough to help you.

The first act upon receipt of a gauge is to determine the baseline pressure of your vacuum pump.  The ultimate vacuum of your system is dependant on the ultimate pressure of your pump.  A reading of 7 micron or less pressure on a TC type gauge typically assures a good pump acceptable for neon production.  If you can get 7 micron on the pump your should get 7 micron on the system allowing for an increase in pump down time for the size of the system.  Once you determine the ultimate pressure of your pump, work your way piece by piece into your system until you get the same pressure throughout your total system.  This is time consuming, but often well worth the effort, as you learn what to look for and the expected pump down times for your system.  keep a log of your pump down times for reference as in times of trouble this can save valuable time as you can more quickly pinpoint the cause of your problems.

Problem areas historically and not necessarily in order of preference.

1. Stopcock leaks
2. Loose hose connections
3. Collapsing hose (slows pump down time)
4. Contaminated oil
5. Other system leaks
6. Worn pump

If you have a worn pump this will show up initially when you dead head the pump for its' ultimate vacuum pressure.  Don't bother doing anything else, get your pump repaired so it is up to speed.  Before you write off the pump or send it out for repair, make sure you are using a new charge of vacuum pump oil like HyVac Pump Oil or HyVac Direct Drive Oil.   Condensation, water contamination in your pump or contamination with other condensable vapors will keep you from getting a good vacuum.  Motor oil is no good for neon work.  Only low vapor pressure vacuum oil is good for neon work.  The oil should spec out to a better vacuum pressure than your pump is capable of providing.   HyVac oils spec to 10^-6 Torr which is a higher vacuum than the pumps are typically capable of, assuring the user with a quality level starting point in determining system pressure.

More sophisticated neon manufacturers also employ the use of diffusion pumps which can greatly speed up pump down times from 150 micron down to pressures below what a standard HyVac 2 stage pump is capable of.  Although the cost is additional again, time is money so if you are making lots of neon, you should also consider a diffusion pump to increase tube production and quality.  Generally more sophisticated gauging will also be required adding additionally to this type of system, but again if it is your primary business, the right tools for the job are good to have.  HyVac has also sophisticated gauging to very high vacuum and also diffusion pumps in both metal and glass configurations along with the fluids that drive them.

More can be learned about neon by clicking this wikipedia link.