[600MRG] restoring old crystals ??

[Joseph Krzeszewski]

John Gibbs wrote:
> 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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You could try Whink brand rust stain remover. It is about 3.5% 
hydrofluoric acid and available in my local grocery store.

I was amazed that anything with hydrofluoric acid was available to the 
general public.

-- Joe

--
Joseph M. Krzeszewski                Manager of Telecommunications
jski at wpi.edu                         Worcester Polytechnic Institute