In my former career job (rf engineer) Rogers material was used for primarily for prototyping because it's dielectric constant is uniform and tightly controlled and because it can be easily "machined" with common lab tools. For consumer goods, though, it is too expensive. Once the circuit was proven, fired alumina substrate was used. In quantity, alumina is much cheaper, ridged, and has excellent electrical and mechanical temperature stability. There are a number of custom and prototype alumina vendors. Here's one of the biggest: https://ceramic-pcb.com.
As others mentioned, mica is still widely available. I've used it too for certain high voltage, low volume applications. It's brittleness can be troublesome in high vibration/shock applications. Environmental considerations over the last few decades have driven mica prices higher. On Sunday, September 28, 2025 at 1:35:59 PM UTC-5 Mac Doktor wrote: > > On Sep 27, 2025, at 12:01 PM, dudu sa <[email protected]> wrote: > > About half a year ago, a few friends came to me and asked if I could make > a Nixie tube similar to the B7971. As one of the few Nixie tube > manufacturers, I thought about it for a while and decided to give it a try. > > > I forwarded this to Eric Barbour, the administrator of the Tube > Collector's Association list. The fact that he isn't ripping you to shreds > is a sign that he thinks this has possibilities and that you're not an > idiot for trying. He's impressed with the repros that have been made so far. > > > On Sep 27, 2025, at 10:28 PM, metasonix wrote: > > Well....I could have told him (for free) this wouldn't work. Only > materials that can be heated and outgassed FULLY can be put inside a > high-vacuum or gas tube. > > This is apparently the stuff he tried to use. It has great dielectric > characteristics, but there is nothing about using it in a vacuum. > > > https://rogerscorp.com/advanced-electronics-solutions/ro4000-series-laminates > > Maybe talk to a company that makes thin film hybrid circuits. They can > probably make a degassable board out of alumina with traces that can be > spot-welded, since they have been making such things for 60+ years. It will > NOT be a bargain. Feel free to repost this to the group. > > https://www.thinfilm.com/substrates.html > > > https://www.coorstek.com/en/industries/electronics/microelectronics/thin-film-electronic-substrates/ > > All modern electronic components are made with some kind of plastics, > epoxies, or phenolics or whatever. None of which can be processed in a > tube. Even Teflon will eventually disintegrate into hydrogen fluoride and > other things. > > If they manage to build a working B7971, they are well within their rights > to charge a very stiff price, at least $500 retail and probably more. > Making such things in the 1950s was easier because mica was cheaper, one > could buy parts and envelopes from third parties, and you could pay bored > housewives 50c/hour to assemble the damn things. > > That price may seem slightly high but Eric knows all about actually > recouping an investment and earning a living. As well as dealing with > customers who can't figure out how to use his products. > > Terry Bowman, KA4HJH > "The Mac Doctor" > > "Tape machines ought to be big and cumbersome and difficult to use, if > only to keep the riff-raff out."—Steve Albini, 1993 > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion, visit https://groups.google.com/d/msgid/neonixie-l/cc98815d-e738-4098-b604-59edf47cda7cn%40googlegroups.com.
