[600MRG] restoring old crystals ??

[Dave]

I had good success with "gritty" toothpaste....the "gel" version is useless

Managed to get an ft243 455kHz crystal up to 474 khz over christmas

Dave

Ww2r/5

-----Original Message-----
From: 600MRG [mailto:600mrg-bounces at w7ekb.com] On Behalf Of John Gibbs
Sent: Tuesday, February 05, 2013 4:06 PM
To: Neil Klagge; SHMRG
Subject: Re: [600MRG] restoring old crystals ??

A long time ago I used a cleaner called "Bon Ami" with a bit of water to 
make a paste which I smeared on a piece of window glass and moved the 
quartz blank in a figure eight pattern to make the ft-243 xtal higher in 
frequency..   Also tried tooth paste with not as good results.  A lot of 
times I wasn't very successful.

A bit of pencil lead on the center of the blank tended to lower the 
frequency a bit. 

Hydrofluoric acid works too.. but totally dangerous and these days 
probably not easily obtained.

73  John / VE7BDQ


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