# If In Doubt, Freeze It ....



## SEIKO7A38 (Feb 12, 2009)

Have any of you had difficulty removing a _reluctant_ screw-down case-back from an old watch ? :huh:

Even if you're using the proper Jaxa type case-back (3-prong) removal tool - and it still won't budge ?









Or worse, still, if you give it that extra bit of turning effort, and the tool slips off - and graunches the case-back ? :angry:

A fellow 7A collector gave me the tip of leaving an ice cube on the case-back for a couple of minutes ....

This makes the case-back contract (even if only a few thousands of an inch) and loosens the threads.

I never actually tried his tip. I went one better. 

Got myself a can of aerosol Freezer - as in RS Components p/n 846-682.



> A powerful non-corrosive refrigerant for use as a rapid and safe method of cooling small components ....


Quick squirt in the middle of the case-back, before applying the case-back tool has the same effect - works wonders ! :thumbsup:

In fact, I'm even wondering if I might even try using it to help seat replacement press-in crystals quicker (with less effort). :huh:


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## SEIKO7A38 (Feb 12, 2009)

SEIKO7A38Fan said:


> *.... and sod the ozone layer.*


Just read the rest of the blurb on RS's website:



> Fully halogenated CFCâ€™s have been replaced by HFC134a/HFC152a with an ozone depletion potential of 0.


Seems the stuff is now 'ozone friendly' too.


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## Rotundus (May 7, 2012)

might just want to be a tiny bit careful using a freeze spray on mineral glass crystals.

have seen rapid temp changes destroy far thicker inspection windows (at atmosphere) on the hi vac stuff what i used to work upon.

could still be worth a try but i suggest not on hard to get crystals just in case.

assume its not worth the effort on acrylic as they are so easy to fit anyway, and assume they would become brittle and crack.


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