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Old 14th August 2011, 04:45 PM   #21
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Default look what ive dug up .

ive found and intresting PDF about emission coatings and how to apply them . this might help you out
normaly used for cathode ray tubes EG TV tubes .

they even quote exact chemical composition . binder . and the ammount of emission . ! prolly all you gona need to know . to make good heaters .

you could fabricate a nice small painting booth . you could use an airbrush to apply the coating .
or just make a small amount of the mixture and submerge the heater wire in it , pass a current through it . and thats all you need .

the binder described there can also be used to get very fine particles of some metals like aluminum , nickel , magnesium , zirconium on your plates and use them as a getter . not a bad idea at all . they will be most active during overload conditions .
this will probably turn out in some grayish colour . aiding heat dissipation

i think the best way of using the plate as the getter is to make a mix of those volatile metals in very fine powder form . take the binder recipe from that PDF and spray it on your nearly finished plates . and warm it in an oven to around 150-200 degrees to drive of the binder and moisture , weld it on your stem and there you go .

i havent found anyone that can supply getter pellets yet . but if you can coat your plate whit a active getter you will be able to make clear glass beasts .
something that comes to mind is that some tubes (not gona say witch ) have an active getter and will survive torture witch would kill your normal tubes

note: extra kudo's for whom may guess wich tube im talking about .

will post and simplified materials list later .

Last edited by v4lve lover; 14th August 2011 at 05:04 PM.
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Old 15th August 2011, 12:32 PM   #22
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Default intresting link + materials

triode project .
Teralab - Glass Blowing - Triode 1

he also shows how to make the pinch that holds everything together . of you could blow some cooler bulb than those . and buy some bases on ebay .

magnesium as a getter ( looks cool . could try magnesium in cooperation whit a barium disc getter
Teralab - Glass Blowing - Evaporation of Magnesium
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Old 21st August 2011, 08:29 AM   #23
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Toshi Tubes

also , i must add that guy has way to much equiptment lying around .
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Old 21st August 2011, 02:49 PM   #24
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Great link, nice setup there. Reminded me of some additional items needed for tube manufacture. I see a tube oven for bakeout of parts. An induction heater for firing the getters. An an annealing oven for slow annealing the glass after glass blowing and sealing. Probably a small spot welder there somewhere. Vacuum gauges and pumps of course. Actually not too much equipment, just the essentials there. I have seen all of those items in surplus stores in the past, but one would have to make a very determined effort to round them all up.

I picked up a used copy of "Procedures in Experimental Physics" by John Strong as mentioned earlier. Great book! Already had "Building Scientific Apparatus" by Moore, Davis and Coplan, another great book. Then there's "Handbook of Vacuum Science and Technology" by Hoffman et all, and "Handbook of Electron Tube and Vacuum Techniques" by Rosebury, "Handbook of Materials and Techniques for Vaccum Devices" by Kohl. Then the RCA "Vacuum Tube Design".

Last edited by smoking-amp; 21st August 2011 at 02:58 PM.
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Old 21st August 2011, 02:56 PM   #25
cfb is offline cfb  United States
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Default Vacuum tube glass and turbomolecular vacuum pump

You must use borosilicate glass tubes and no they are generally not available locally for most. The tubes will have to be special ordered from a laboratory or scientific supply house. Schott is a leading manufacturer but there are others; the problem will be minimum order sizes are geared to the large scale and not small R&D or hobbyist activities. In other words, it is going to cost you for a small order unless you can locate some on the surplus market. For example, a case from Cole-Parmer in the 51 mm size is $360 see WU-34742-54 Glass Tubing, 51mm;

Glass Tubing And Glass Tubing - Cole-Parmer Catalog

Regarding vacuum pumps, you will need a turbomolecular vacuum pump and control power supply in addition to the roughing/backing pump stage and diffusion pump. You might find one on ebay that is working but it will still run about $800 on up to 3 to $5,000. Factoring in all the glass blowing tools and sundry supplies and special materials that are needed; I just don't see setting up a working lab for under $3,000 at the minimum.
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Old 21st August 2011, 03:51 PM   #26
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If one can find an oil diffusion pump, then the turbo pump isn't needed. Although the diff. pump does require a lot more support in the way of valves, water cooling and a cold trap. (both types need a good roughing pump) I would say that Ebay maybe should be a last resort, since most of the specialty vendors for this stuff will be pushing the max prices the market will bear and including refurbishing costs. A surplus store in the right area (old semiconductor production equipment say), or a university surplus store, would be much better bets for finding a good price on vacuum equipment I think. One will likely have to do some cleaning and refurbing (new heater cartridge for the oil diff. pump, cleaning burnt oil deposits out). If a turbo pump and drive electronics is located for a reasonable price, then by all means go for that, so much easier to use.

Have to agree on the high expense for a full VT setup though, so many items needed for glass blowing, annealing, gettering, materials, welding.... Might as well round it out with a few more items so you have a semiconductor fab too.

Last edited by smoking-amp; 21st August 2011 at 04:06 PM.
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Old 21st August 2011, 04:28 PM   #27
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On surplus turbos:
Be aware of possible damage from items having fallen into the turbo while in operation (break a glass ion gauge and it all heads for the turbo inlet, or say a melt down of stuff in the vacuum...), bent or out of balance turbo vanes from store visitors or disassembly and subsequent handling issues, contamination from toxic chemicals (semiconductor use especially), failed bearings, seized rotors, burnt motors (some can run at 20,000 RPM and up, there is no such thing as a slightly out of balance working turbo). I wouldn't buy one off Ebay without some guarantees and pre-testing and right of return.

Last edited by smoking-amp; 21st August 2011 at 04:45 PM.
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Old 21st August 2011, 05:07 PM   #28
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hmm there is a indian company making the nickel dumet and NI48/FE52 wire . JLC Electromet - Product Range

they can provide nearly everything

plate material nickel sheet strips ni200 /205 probably 40mm strips 0.1 to .25 thick for anodes
suport wires 1 and .5 mm NI48/fe52
dumet wire .3 mm

your going to need to source glass from a good supplier
20-22 mil is normaly used as stems i got a broken rca DHT on my desk right here whit a 20mm stem thickness
30-40 mil to make the bulb
4-6 mill for the pumping stem

for grids you can make nice grid supports from straightened 1mm ni/fe wire . and use some good conducting wire wrapped around it . to make it weld . or take bad conducting wire like nickel .25 wire and use copper grid posts

next is tungsten . wich comes whit its own problems as i have not the slightest clue on what thickness wire would be right at wich lengt to make a good wire heated to 700-800 degrees celcius at normal operating voltages

but the rca vacuum tube design booklet gives the formula to calculate the wire lenght its on page 23
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Old 21st August 2011, 09:31 PM   #29
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Here's a PDF of the Varian diffusion pump brochure (no affiliation...). Check out the AX-65 and HS-2 pumps on pages 4,5 and 6,7. Stainless steel construction, 3 stage jets and ejector stage design. Heater power at 200 Watt and air cooled operation for the AX-65, or 450 Watt and water cooled op. for the HS-2 model. Perfect for a home lab setup. Anything bigger gets into kilowatt power consumption. There are even smaller diff. pump models around for vacuum instrumentation like leak detectors or mass spectrometers that would work fine for Vac. tube evacuation.

I've used an HS-2 system (with an Airco-Temescal 3 inch slide valve, Varian water cooled inlet baffle, a bronze inlet flange machined to fit Corning Pyrex 3 inch glass beaded pipe, a Varian 2 stage mechanical backing pump, gauges...) for many years. It's in storage now I think, I haven't seen it for a long time. (got replaced by a Balzers Turbo) A great little oil diff. pump for hobbiests, indestructable, reliable, high performance.
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Old 22nd August 2011, 10:32 AM   #30
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Originally Posted by PhilippeS View Post
See the video on this page and maybe the manufacturer can help you

Thanks for the link!!!!!

It's pure art ...
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