Wrote these notes on what I understood the video was showing. This man is hand-making vacuum tubes of an early-1920's design with some design simplifications.

Wrote these notes on what I understood the video was showing. This man is hand-making vacuum tubes of an early-1920's design with some design simplifications. Part 1 The video begins with the final product of his labors. This vacuum tube is a triode - it as three elements (or what he terms electrodes): a filament, a grid, and a plate. The elements are inside a glass envelope, which was sealed after evacuation on the top, leaving the little swirl of glass. The wires for the elements (or electrodes) are soldered into the pins of this blue plastic base he has. To me, it looks like the WD-11 vacuum tube of the early 20's, but I think he patterned it on something else. 0:12: Cutting the metal that will become the plate. Heh, odd choice of tool, but whatever works! 0:47: Bending little tabs on the end of the plate material. Later on he is going to wrap this metal on a mandrel into a cylinder, spot weld it closed, then spot weld a little wire to it (both supports it and conducts the electrical current from it). This forms the plate electrode. In this design the filament in mounted vertically in the center of the tube, and all of the elements are mounted concentrically to it, so its usually the outer surface of the plate you see when you look at tubes like this. This design uses the filament as the cathode. 1:58: Making the grid element. This is the element that you vary the voltage on to change the current flowing from filament and plate. He is using a basic helical design, thus the winding of the wire around a small mandrel. The grid is spaced widely to not impede so many of the electrons in the path from the filament to plate - but closely enough that he can still get enough control of that flow when he puts a voltage on the grid. The little loops on the ends of the grid are a nice touch - I don't think I've ever seen that on a real production vacuum tube. The grid wire is much thicker that would otherwise be used in a production tube - BUT, if you do make it with fat wire, it is self supporting and that saves a lot of work in adding in additional supports. 2:19: Making the filament element. It is very much like a incandescent light bulb filament but without the coiled-coil design you see in a typical bulb. He is straightening the filament wire before welding it to the supports. Early tubes used the filament as the cathode and the plate as the anode. Some of these used straight tungsten wire, which you would have to get quite hot to 'boil' off the electrons. Then they figured out that dipping the filaments in metal oxides reduced the temperature you had to heat the filament to. I don't think he did such coating here. 2:59: Now we are cooking with gas...he is beginning the glasswork to construct the envelope. Glass workers can correct me, but I believe he pre-warms the glass, the hits it to melt it enough to allow the tool to flare the end of the tube, then uses the carburizing flame to bring it back down to temperature slowly to prevent it cracking from shock? 4:23: Neat tool for 'cutting' glass tubing. He scores it first, then uses this loop heater to cause the glass to crack through, releasing the part. From here we see some special tooling for turning the flared tube into the base of the envelope, and squishing the end in preparation for the installation of the electrical leads that will pass through it. 6:19: He is assembling the leads for the elements. The wire he welds all of them to is just for support during the later steps. I wonder if the dark areas of the wire are part of a treatment he did to make a good metal-glass seal. Good sealing here is essential - if a microscopic gap opens up when the metal and glass heat up during usage, gas will get into the tube, change its characteristics and given enough of it - ruin the tube entirely. 6:49: Leads are sealed in glass envelope base. Placed into a little oven to anneal/cool slowly. 7:36: Making the body of the envelope. No special seals here, but some nice glasswork in making the rounded end and attaching the evacuation tube. 9:50 - A whole pile of glass tubes. Job well done. Part 2 He is welding on the electrodes - first the filament, then the grid is slipped over that, then the plate cylinder, then the support/return for the filament. 0:37: It appears that he is doing a cleaning and surface preparation process here. Oils, organics, fluff, all cleaned away. Everything has to be clean as we move toward sealing and evacuating the vacuum tube. 0:44 - The base and body are joined. 1:20 - The evacuation. not only is he evacuating the tube, he is heating the tube to drive off moisture, gases stuck on the surfaces within the tube. You can really see this at 2:05, where he uses what looks like an RF induction coil to heat the internal elements. The digital display must be the output from some high vacuum gauge. Later on in the video you see some special pumps he has built, but it isn't clear what he used for this tube process. I think the sound in the background is the pumps at work. Perhaps a combo of a roughing pump and mercury pump? 2:15 - Lights up the filament for the first time, all in the effort to get everything besides the elements out of the envelope. Also a check that it keeps heating for an extended period of time and doesn't just fizzle. 2:26 - The sealing operation; a set of flames melts the little tube at the top of the envelope, locking in the vaccum and flavor. 2:58 - This part impressed me the most - he molded his own tube bases. He would have had to selected a material that can hold up to heat well, as the heat from the filaments will conduct right down to the base pins, melt and eventually degrade the plastic surrounding the filament pins. 3:20 - Testing the tubes, using a custom rig to plot curves much like you'd see in tube data sheets. 4:19 - All right, time to use the tubes! first, he has it in a little regenerative receiver, then a CW (for Morse Code) transmitter, then what seems to be a VHF transmitter using a bit of old 450 Ohm transmission line as the tank circuit. 5:01 - Finally the man himself, Claude Paillard, and some of his other work. Love the jacket at the mill. I wrote to him about how awesome his tube project is and to find out what the heck that music playing in the background was, and he wrote back: "About the triodes...they have numerous 'children'...in the 2004-2005 8 or 10 were on a very low power transmitter (around 100 milliwatts) with a quartz on 3580 khz...with a lot of 'local' QSO in France. One of these is in the A.W.A museum in Bloomfield N.Y... Around 2009 we go to one watt of RF always Xtal driven, on 3560 kHz...the one on the picture has made more than 300 QSO all over Europe...The last is with a pair of triodes running 5 watts output on 80-40-30-20 meters, with VFO of course...and worldwide received With a careful look, you can identify the 'box' as an old surplus 'BC375 Tuning Unit' There also others use, but the main project was to return to 'good old time' of our fathers in Ham radio" Check out his website at http://paillard.claude.free.fr/ http://paillard.claude.free.fr/