The origional Moog modular panels were printed direct onto the aluminium
face of each panel, how they did this I dont know but I would like to replicate this..does anyone know how it was done and is it possible for me to replicate the process?
The common method was silkscreen. Don’t own any old modules to see if that was how they were done. The ‘modern’ method is pad printing. That method is how most of the things you touch in todays world are done. (Cell phone covers, remotes, car dash controls, etc. Too expensive for short run items.)
The face plates for most electronic test equipment was silk screened back in the day. (Heath, Dynaco, McIntosh, Tektronics, etc.) Not too expensive to do yourself. And with photoetch screens, detail is better and easier than in the past.
http://www.synthesizers.com/faq.html#moogdiff
from the synthesizers.com FAQ page:
“Moog panels used anodized aluminum that was then etched to expose the lettering. This etching process is very dangerous since it creates toxic fumes. On top of that, the artwork doesnt have consistent widths which causes the exposed edges to be inconsistent. Synthesizers.com panels use a more complex masking process, painting, then silkscreen printing. This is a bit more work but we don’t have to endanger our employees and the panels look great.”
All good, but I’d like to mention that Moog modulars are one of the few synths I can take 40 years later and completely clean the panel with even the harshest solvents.
I can’t take acetone, MEK or even just soap and water to some synths.
They’d be damaged forever.
But they don’t even phase the Moogs. 
thanks for the info..I did notice on a Moog 3C a few years ago that the letering and dials were not white …they were the base aluminium colour which supports the etching process..I would love to have seen photos of the process, I guess for me I have to consider the silkscreen method if its feasable.