I used mild soap and water but the dial still has a discolored film and what looks like grease spots. The paint looks and feels like it was applied to the outside of the glass rather than the inside.

I've had good luck cleaning up airplane dials but this is my first time with a 1947 slide rule dial and it looks fragile so I don't want to mess up.

What can I use to 'restore' it without damaging the paint?

Painted glass dials vary greatly in quality. Mineral spirits should not be a solvent to very old paint, and should remove grease well. Follow with soap and water. Whether mineral spirits or soap and water, you should test in an inconspicuous spot, as some dials hold strong and some wash away.

T.

Daniel,
First thing is to scan it 1 to 1, before any further wash jobs, so you have a copy of the original, in case you have to reproduce it by whatever means. I've been successful using Adobe, MS Visio, and clear waterslide decals to reproduce a couple.

marv

:I used mild soap and water but the dial still has a discolored film and what looks like grease spots. The paint looks and feels like it was applied to the outside of the glass rather than the inside.
:
:I've had good luck cleaning up airplane dials but this is my first time with a 1947 slide rule dial and it looks fragile so I don't want to mess up.
:
:What can I use to 'restore' it without damaging the paint?
:
:
:

I have a question about decals. First of all do you invert left to right before printing them so the decal will be on the inside (rather than the outside) of the glass/plexiglass replacement dial, and secondly, is common plexiglass good for slide on decals?

:Daniel,
:First thing is to scan it 1 to 1, before any further wash jobs, so you have a copy of the original, in case you have to reproduce it by whatever means. I've been successful using Adobe, MS Visio, and clear waterslide decals to reproduce a couple.
:
:marv
:
::I used mild soap and water but the dial still has a discolored film and what looks like grease spots. The paint looks and feels like it was applied to the outside of the glass rather than the inside.
::
::I've had good luck cleaning up airplane dials but this is my first time with a 1947 slide rule dial and it looks fragile so I don't want to mess up.
::
::What can I use to 'restore' it without damaging the paint?
::
::
::
:
:

CF,
I replaced a plastic dial on a Heath AM tuner. It blew of the panel in the dishwasher, and ended on the heater element. Made a dup using MS Visio, and sent it to a trophy/engraver shop. He was able to make an exact copy, then used a laser engraver (PC controlled) on the plastic. Masked the entire plastic, then engraved thru the tape, making it easy to fill with white paint. Have a personal friend with a framing shop, and usually find waste scraps of glass for dials. Use the mirror image print mode for the decals on the back (preferred) of glass dials.

marv

:I have a question about decals. First of all do you invert left to right before printing them so the decal will be on the inside (rather than the outside) of the glass/plexiglass replacement dial, and secondly, is common plexiglass good for slide on decals?
:
::Daniel,
::First thing is to scan it 1 to 1, before any further wash jobs, so you have a copy of the original, in case you have to reproduce it by whatever means. I've been successful using Adobe, MS Visio, and clear waterslide decals to reproduce a couple.
::
::marv
::
:::I used mild soap and water but the dial still has a discolored film and what looks like grease spots. The paint looks and feels like it was applied to the outside of the glass rather than the inside.
:::
:::I've had good luck cleaning up airplane dials but this is my first time with a 1947 slide rule dial and it looks fragile so I don't want to mess up.
:::
:::What can I use to 'restore' it without damaging the paint?
:::
:::
:::
::
::
:
:

Thanks everyone for the interest and suggestions.

Marv, you are so right. I always keep the flatbed scanner warm whenever I start working on a dial face - you just never know.

:I used mild soap and water but the dial still has a discolored film and what looks like grease spots. The paint looks and feels like it was applied to the outside of the glass rather than the inside.
:
:I've had good luck cleaning up airplane dials but this is my first time with a 1947 slide rule dial and it looks fragile so I don't want to mess up.
:
:What can I use to 'restore' it without damaging the paint?
:
:
:

Daniel,
Its very unusual to have the silkscreen on the front. Is it possible that the orig. had a clear primer applied to aid the silkscreen bond to glass, but has turned dark with age. Until the invent of epoxy paints, don't think enamel bonded well to glass. Most of the old dials I've found, the paint flakes off easily, except in rare cases. That might be subject for some research. As for cleaning, you could start with more aggressive glass cleaners, since mild soap doesn't work to remove the greasy film. Find a small inconspicuous spot on one of the numbers, and apply the cleaner with a toothpik for a test of the paint, then test on the greasy film, if it doesn't attack the paint. If that fails, move up to more aggressive cleaners like 409, and repeat. Automotive glass cleaners may be an option too. Denatured alcohol is a good glass cleaner also. Good luck

marv

:Thanks everyone for the interest and suggestions.
:
:Marv, you are so right. I always keep the flatbed scanner warm whenever I start working on a dial face - you just never know.
:
::I used mild soap and water but the dial still has a discolored film and what looks like grease spots. The paint looks and feels like it was applied to the outside of the glass rather than the inside.
::
::I've had good luck cleaning up airplane dials but this is my first time with a 1947 slide rule dial and it looks fragile so I don't want to mess up.
::
::What can I use to 'restore' it without damaging the paint?
::
::
::
:
: