On 05/15/2012 01:40 PM, kay486 wrote: > Hi there, well, if you like videos about homemade tubes, chec out this guy. > He makes all sorts of tubes and he explainst the individual steps really > well. > http://www.youtube.com/user/glasslinger/videos
I've just watched the X-ray tube making video (bandwidth limitations) and I saw one thing that made me want to cry. He fired the getter BEFORE he tipped off the tube. That's bass-ackwards. All the getter did was to cause the diffusion pump to back-stream a little to fill the void. The failure of his tube to achieve a high vacuum was evident in the internal flash-overs he experienced. A hard vacuum will not flash over. With enough voltage there would be field emission but that is invisible. A getter can increase the vacuum 3 or 4 orders of magnitude immediately and another order or two after some operation. If his diff pump can do 10-7 Torr then firing the getter AFTER tipping off will produce 10-9 to 10-10 Torr. That is well into the range of hard vacuum. Another thing I found odd was how he joined the feedthru units to the tube. I've never seen anyone pick at a joint like that with a carbon. The standard technique is to bring the two pieces together, heat until quite soft, then work the two pieces back and forth a bit to make the glass flow while gently puffing on the blow hose to maintain diameter. I should also note that a lot of what he does on the glass lathe, us neonists and many scientific glass blowers do by hand. It takes more skill and practice but that can make up for equipment on a limited budget. I did like his little resistance welder. Nifty kit. John -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
