[Milsurplus] fixing loose meter glass, the easy (lazy) way.

[Bill Cromwell]

Hi Mark,

I'm that guy. I couldn't find a suction cup small enough but that's
exactly what I was going to do. I have some meter movements around here
that don't come undone without damage. The mil ones that are sealed are
sealed very well but I don't think the glass can come loose. It can
certainly break.

I didn't know if the meters in the RAK were made to disassemble until
opened the radio. There are three screws that hold the meter in the
front panel of course. I removed those and the wires from the terminals.
Then there are three more screws around the circumference of the
two-piece meter body. With those screws removed the rear half along with
terminal and the entire meter movement slide right out the back of the
case. The front half has the glass, a brass ring that fits the perimeter
of the case immediately behind the glass, and the zeroing screw. So I
cleaned off the old cement and carefully added a tiny bit of silicone
sealer/adhesive and pressed the glass back in place. None of the silcone
goop shows (grin). I am leaving it to cure overnight and tomorrow I will
reassemble it and install it back in the RAK.

Had I been unable to disassemble the meter I was going to put a spot of
silcone on a broom straw. glue the end to the outside of the glass, and
then use that to maneuver the glass to make the repair as you have
outlined. After all the dust settled I should have been able to remove
the straw and the silicone pimple. I don't think the silicone would come
away cleanly with a plastic lens.

Thanks for your comments. Other list members may need to fix up an old
meter and the info will be handy.

73,

Bill  KU8H


On Mon, 2012-10-29 at 13:11 -0400, Boeing377 wrote:
> The guy fixing the RAK? wrote: "I only wanted to fix the meter glass."
> 
> I've faced similar problems, most recently on my ARR 7 S meter. 
> 
> I use a toothpick to put some tiny dabs of clear RTV silicone adhesive on the periphery of the internal circle to which the glass was previously adhered. I do this with the meter facing up so that the glass falls away from the mounting circle and allows access. Usually the glass resting against the face does not permanently bend the meter pointer, rather just deflects it and it springs back when the glass is lifted off.
> 
> I then turn the meter so that the glass is facing down and use gravity to my advantage. The RTV (before it sets up) allows slight movement of the glass to get good positioning. Any RTV slop over can be easily cleaned up with an Xacto knife once it has dried. 
> 
> I have pondered the idea of making a vacuum device (taking vacuum from my de soldering station) to hold the glass and allow it to be pulled around with positive control, but haven't done it yet. I think I'd use a very flexible (floppy) suction cup and feed a vacuum pipe into it.
> 
> I ruined a couple of surplus meters trying to take them apart to fix things. That's how I was driven to this lazy method. I've also used it to re-attach glass tuning dial covers. 
> 
> 73
> Mark
> AF6IM
> www.parachutemobile.org