[time-nuts] How to open solder-sealed OCXOs?

[Robert Atkinson]

Hi Graeme,
A technique I've found useful is to first remove the corners of the outer can by filling across them. I then rake out as much of the solder along the seams with the back edge of a disposable "snap-off" craft knife / box cutter. Finally wedging the sharp edge to break the joint. Removing the corners releves the stiffness and allows the edge of the can to be bent back in a straight line rather than a rough set of bumps. 
On many hermetically sealed aircraft instruments they put a "tear" wire at the bottom of the solder joint with a tail sticking out. You just grasp this and pull. While the joint geometry on the aircraft instrument is designed for this (typically with a non-metallic packing under the wire) and your OCXO isn't, it is a good idea to leave the case slightly flaired and lay a length of tinned copper wire in it before ligthly soldering over the top.  


Robert G8RPI.


________________________________
 From: Graeme Zimmer <gzimmer at wideband.net.au>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
Sent: Sunday, 2 February 2014, 8:50
Subject: Re: [time-nuts] How to open solder-sealed OCXOs?
 


> What's the best way to open an OCXO in the typical solder-sealed tinned
> steel can?

Use a high wattage iron to melt the solder at one point, prise the gap 
open with a flat screwdriver, then work along the join.

Solder is soft. so once you get it started you should be able to roll it 
open like a can of tuna.

You could use a dremmel and a cutting disk, but the vibration might kill 
the Xtal.

Alternatively, a hot air gun might work if you are quick enough not to 
cook the innards.

............ Zim

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