[Milsurplus] Crystals and etching.

[Kenneth G. Gordon]

On 31 Jul 2022 at 19:27, hwhall at compuserve.com wrote:

> 
> >So, at one time, crystals were made in-house at Midland, and in the '30's it was a mom and pop 
> operation for the most part, so have wondered why it could not be restarted as a cottage industry 
> again.< I suspect that it could be, but the economics of startup &material costs could be a show 
> stopper given the rather small market for crystals. I wonder if AF4K Crystals had looked into the 
> possibility of manufacturing. It might make more sense for someone to do as an avocation without 
> the need for making a profit. 
> Wayne
> WB4OGM

Some time ago, I knew a fellow in the midwest US somewhere who was making and selling 
crystals. He owned an ex-military (I believe) crystal-grinding machine which ground several 
crystals at once. I think at least 8, possibly more. It used a fairly large, round holder for the 
blanks, and spun them all against some sort of grinding medium.

He died rather suddetly of cancer. I have no idea of what happened to his equipment. I 
believe I still have an e-mail or two from him somewhere here. If there is any interest I will try 
to dig it out. His family may still have his equipment.

I also have here a book which I believe was published for the U.S. Army on the exact, 
somewhat involved, procedure for making quantities of crystals. That book may have been 
mentioned here.

Lastly, Dennis mentioned "buffered HF solution", and I am not sure what that is. However, I 
have used Whink Rust Remover, available at most supermarkets in the home cleaning 
supplies section, to both etch crystals to chosen frequencies and to clean them properly.

As Dennis mentioned, REALLY cleaning a crystal enhances its activity very, very noticably.

Whink contains 1% HF and it is, apparently, safe enough to be sold in household supplies 
sections of most supermarkets.

There is also an HF solution available at hobby supply stores which is used to etch designs 
on glass. I am not sure of the percentage of HF it contains, but it is more than 1%. This stuff 
is sold in many, if not most, hobby stores so it has to be relatively safe too.

Pure HF is literally deadly stuff, and I would never care to use it.

One can buy it at University chemistry stores. It must be stored in containers lined with a 
thick wax or in special plastic containers. HF is very dangerous (I repeat myself). It can 
penetrate human skin and will then dissolve the bones....among other horrible things it does.

HF is VERY hygroscopic (sucks water right out of the air) too.

When I have used Whink (yes, the "h" is part of the name) to work with crystals, I used small 
plastic containers to both put the crystal blank and the Whink into. Whink "moves" a crystal 
some 10 kHz higher in frequency per hour, and leaves the crystal VERY clean. I handle the 
crystal blank with plastic or even wooden tongs, then wash it with cold running water.

My idea was a project to "make" a series of 40 meter crystals beginning at 7001 kHz, every 5 
kHz to the top of the band. I had thought that after I got those done, I could then, perhaps, fill 
in the spaces between the 5 kHz sections to 2.5 kHz.

To that end, I had bought as many FT-243 crystals at the high-end of the 6 mHz range as I 
could find. Those are cheap since they aren't usable on ham frequencies. I have around 100 
FT-243 40 meter/capable crystals now, but have not been able to arrange the time to get to 
this project recently.

I had the same idea to try this with 80 meter and 160 meter crystals, but 80 meter crystals 
are very hard to find any more and 160 meter ones are almost unobtainable at all.

Anyway, Whink "wears out" as it is used. The movement of any chosen crystal starts out, 
even at only 1% HF, fairly quickly, then slows down as the HF gets used up. Also, one MUST 
keep the container with the Whink and crystal in it closed up tight as the Whink will evaporate 
completely over only a few days and that stuff being in the air one breathes is not good for 
one's sinuses. (!!!)

Anyway, that's my story, and I'm sticking to it.

Ken W7EKB