Hi
On Aug 2, 2013, at 11:27 AM, Magnus Danielson <[email protected]> wrote: > On 31/07/13 23:59, Alberto di Bene wrote: >> A really fascinating story in pictures of the preparation and >> manufacture of quartz crystals for radio communication. >> Dating back to 1943... how times have changed... >> >> Copied from another list. >> >> http://archive.org/details/6101_Crystals_Go_to_War_01_20_16_21 > > Nice video. Would be interesting to know what etching and neutralizing agents > where used, The etchants were mainly ammonium bi-fluoride based. The "crystal etch" referred to in the movie was a commercial product with a bit more than just HF as the active agent. Neutralization was mainly water and baking soda. > as well as the cooling and grinding agents. What ever they used for grinding, there were a series of particle grades used. It was a multi-step process. Different shops had favorite grinding powder suppliers. > Also nice to see the relatively low-tech they used with pencil markings. > Nice combination of techniques to get orientation and faults located. > The cut-angle for the GT-cut seemed to be well established in the mechanics > of the cutting tables. ….. or put another way, the table fixture was designed specifically for the cut they were doing. > > Would be interesting to see a similar movie from a modern facility. ….. but would the modern tax payer want to pay to have it produced? That one was done on government money. Just as all the "good stuff" was left out of that movie, I suspect the same would be true of a modern one. Bob > > Cheers, > Magnus > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
