DIY Tubes and the DIY Tube video...

[WBear2GCR]

I finally got to see the DIY dude's video:

http://www.dailymotion.com/video/x3wrzo_fabrication-dune-lampe-triode_tech

today...

First thing I noticed is that he build all of the gear to make the tubes.
The pumps, the ovens, the glass forming stuff.
Notice the Mercury diffusion pump that pulls the last bit of vacuum??

But, a few things were skipped in the video.

I was left wondering how he activated the filament?
That usually requires a thorium material since it is a DHT tube.
Also, usually the plate is not kept bright nickel alloy, it is oxide coated, he's not doing that...

I also wondered about his induction heater - that was the big fat coil that was shown cooking the plate under vacuum. Is it RF? Or magnetic induction?

The tube socket seemed a bit odd... nice that it was split pins, but how are the tube wires connected to the pins? No solder??

Also interesting was that they/he showed a mold for making the tube sockets, I wondered what he used for that? It has to handle some reasonable temps, which is why ceramic or more usually Bakelite was used. Bakelite doesn't come out blue. 

Then sitting here typing, I thinks to meeself, meeself, if I werto make mee a toobe, watt wood eye make?? Aint gonna be no tiny leetle receiving triode!

Seems to me the thing to make is something more like an old buzzard TL/TH-1000!!

YEAH BABY!!

Anyone going in on it with me??

           

                       _-_-WBear2GCR

[Ed/KB1HYS]

The problems get simpler if you don't try to make an efficient or high gain tube.
thorium-tungsten welding wire is available, and might work as a filament.
Also plain tungsten wire would work, although it would require high filament current to have the reasonable emission. 

All in all that guy has taken home brewing to a whole new level.  I though the regen with the spiderweb coils was cooool....

[AB2EZ]

I agree that this is an inspiring, must-see video.

[I wonder if I can home-brew some FETs for a new Class E transmitter?

Maybe a reed relay:

Reed = Drain-Source;
Bottom of coil connected to Source;
Top of coil = Gate)

It would work pretty well at VLF.]

Stu

[W3RSW]

"The tube socket seemed a bit odd... nice that it was split pins, but how are the tube wires connected to the pins? No solder??"

Oh, that one's easy....  "RoHS Compliant" to be sure   Baby Blue SHIPPO stuff, ya know.

Yeah, it sure was an inspiring video.  I'd guess by the coil that it was 10Mhz induction heating.  Too bad it wasn't tuned to 3992.  But then again, what's the bandwidth for an RF induction heater?  Must be what I hear everyday wiping out 3885.

'bout the 100Th's, - Well if we can't make new ones, maybe the investment required to recondition 100th's, 304tl's, etc. wouldn't be so involved or expensive.  Probably way to expensive to be done on smaller tubes commercially but might be doable by dedicated hams.  Hate to say how many shot fil's are in my collection.