Saturday, February 24, 2024

Coloring Engraved Letters

There is a trick to make the stamped lettering on handguns stand out for photography so Colt's Patent Firearms Co. is very visible.  I think the technique involves spreading a thing layer of white paint across the surface then wiping away the surface layer.  Keep the gun flat until the paint or White Out dries.  When your photography session ends you use some solvent to clean out the letters you were trying to make more visible.

I ask because I am thinking a couple steps ahead about setting circles.  These are practically obsolete today with modern go-to controllers but they are a common component even on modern mounts and provide a backup navigation method.

My thought is to put a 4" diameter piece of black acetal on the rotating table (which still needs the Sherline CNC upgrade).  Write program to rotate the table one degree at a time, cut a 1" line, use the font library to scribe 0, then one degree rotation, cut a .25" line, ditto for 2, 3, 4.  Then a .5" line. Return to .25" lines until the next 10 degree line.  Continue around the circle.  Now apply a layer of white (or maybe even phosphorent to make it more visible in darkness) paint to the  surface.  Wipe off excess.  Allow paint in the scribed lines and numbers to dry.  Paint really does not stick to acetal.  Apply clear layer of polyurethane to hold the paint in place.  This seems like a solution.  

Why acetal, not carbon fiber?  There is no load on setting circles and they are about the same density as carbon fiber even a little lighter.  Aluminum is also a choice and paint will stick to it.


  1. There are adhesive backed printed degree wheels out there, easily converted to setting circles. Save yourself a lot of time, money and sweat.

  2. If you start with white acrylic, and paint the surface with a couple of coats of black paint, and then engrave the surface the white shows through. This is good enough for instrument panels, not sure if it would work for the accuracy you want.

    The only other thing I've seen is etched brass for clock faces. Though depending on the size, the brass may be too expensive. (Not sure the dimensions you are working with...)

  3. I recall a million years ago having an aluminum Social Security card replica made by a man working on a store sidewalk (like a shoeshine booth). It was embossed and he used a crayon to fill in color for contrast. It seems that for temporary purposes that would be easier than paint.