I was recently cleaning the 'S' meter from a Hammarlund HQ-160 and found a
potential disaster lurking.
The meter cover had been painted around the edge in some type of glossy red
paint, and the dial bezel of the radio surrounding the meter had been
painted in aluminum paint, some of which was slopped onto the meter cover on
top of the red. I tried a couple of 'benign' solvents that should not affect
the cover plastic, and alcohol had some effect on the red paint. I applied
it with a Q tip onto the red and tried to keep it wet for a couple of
minutes, at which point I could scrape much of the red paint off with a
'soft' scraper [thumbnail]. Under the red I found several sharp scratches in
the clear plastic filled with the red :-(
Along the bottom edge was the aluminum paint which, on the bezel, was very
resistant to everything but paint stripper, so I decided to simply sand off
that edge as well as the two sides that had the sharp scratches in the clear
plastic. I used 400 then 600 grit paper wet with water, and finished with
Novus.
All well and good, but when I took a photo of the finished job, I noticed
some what looked like runs in the meter face decoration. Smudges of dark
brownish goo seemed to have accumulated in the 'troughs' at the outer ends
of the scale markings. It seems that the acohol fumes or water vapor entered
the meter around the edge while I was working on the paint, and caused
something to liquify and run.
I removed the cover and carefully tested the lettering with a water damp
cloth and it was okay with that. Wiping over the face with the soft damp
cloth removed the 'runs' as well as a layer of yellow-orange film that
seemed to been exuded from the dial base material, both front and back.
I was very lucky that the letteing did not melt and run due to the
relatively benign solvent fumes that crept in around the cover edge.
Neil S.