This is too funny : ) ! McMaster is on my short list of go-to suppliers for prototyping material. Yet, it never would have occurred to me that they might carry mica. Thanks for sharing.
On Monday, September 29, 2025 at 10:45:52 AM UTC-5 J Forbes wrote: > you made me look. > > [image: mica.jpg] > > On Monday, September 29, 2025 at 7:56:08 AM UTC-7 Neil QQ wrote: > >> 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/c38ee925-d3c3-4926-bb49-7deabf99d20an%40googlegroups.com.
