Here is the condensed version I originally posted. This was taken from an Ithaca Service Manual Ca 1981 & was given for refinishing the Perazzi O/U shotgun. This contains everything essential from Ithaca's instructions.
To Repair or Restore Color Case
1; This is a serious problem on guns that have been used extensively.
Equipment Required:
a. Cold blue (we use 44-40)
b. “Q” tips (cotton swabs on a stick)
c. torch or other heat source
d. Paint remover (we use “Kwick”)
e. Fine steel wool
2; Procedure:
(1) Remove everything from the receiver.
(2) Remove lacquer from the receiver using “Kwick” or other liquid paint remover
(3) Wash receiver in a good solvent or boil with detergent.
(4) Using your heat source, heat the receiver to a point where liquid cold blue will dry almost instantly, (about 160°F)
(5) Using a “Q” tip, draw squiggly lines or whatever is necessary to match existing color hardening.
Note* If you have polished the receiver to bare metal, space your lines about ¼” apart on the first pass, then fill in on a 2nd pass.
(6) Using fine steel wool dipped in oil, remove the oxidation from the receiver. Be careful not to remove the color.
(7) Wash in good solvent. Do not touch before applying lacquer.
(8) Spray with acrylic plastic from “Koloid”
(9) Reassemble gun & return to a satisfied customer.
Note** This procedure does not affect the hardening. It only restores the color.
Note this statement; "draw squiggly lines or whatever is necessary to match existing color hardening". When I used this process I did not draw squiggly line similar to cyanide hardening, but did blobs etc to look more like a charcoal job. Again I am not absolutely certain on this but I think the Perazzi frame was likely not made from a carburizing grade of steel, but a heat treatable alloy. True carburizing/case hardening is not generally suitable for a steel having excess of about .2-.25% carbon, ala SAE 1020 etc.
Note that if using a "Torch" as the heat source a concentrated heat is not used, but part should be heated as uniformally as possible up to the desired temp. A simple propane torch is quite adequate, acettylene equipment is unnecessary. It could be simply put in the ordinary kitchen oven with the temp turned down about as low as it would go.
Last edited by 2-piper; 02/04/09 03:09 PM.