[Milsurplus] [Boatanchors] Smart People: Gassy Tubes Reversable?

[J. Forster]

>  Thanks for the clarifications. I was imagining that if a few days
> operating under the stated conditions helped clean them up, maybe just
> longer operating & idle time might convey some similar benefit, perhaps
> by keeping the getter material hotter longer.

It's a tradeoff. There may well be a benefit from running things all the
time, because the units will reach thermal equilibrium and stabilize
there. Once the gas is cleaned up, I don't see much purpose otherwise.

> >gas diffuses through glass faster at higher temperatures

I understand how a hot gas may diffuse faster through glass but I didn't
foresee how hot glass made it so.

Glass is not a true solid. It's a supercooled liquid. This area has been
extensively studied. And all glasses are not the same.

>     >I'm not convinced outgassing is a big problem

> That may very well be true. It gets a lot of blame, though, in casual
> conversations. Wish I
> knew more about the mechanics of the manufacture process. In the
> meantime, I'm going to hunt down that long article about getters.

There are videos of tube making on YouTube. There is also a video by Norm
Krim (SK) on TechTV.

There are many things in ham lore that just ain't so.

> An investigation of the actual gas components sounds like an interesting
> study & an interesting report. I wonder if anyone outside of the tube
> manufacturers had ever tried it? Don't think I could justify buying a
> spectrometer for just that one use. Though if one were cheap enough...

I got an Ocean Optics USB fiber spectrometer a few years ago. Might be fun
to try sometime.

Best,

-John

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