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Specs for Copper
Here are the applicable specifications:
MIL-C-14550B
Copper in color and matte to a very shiny finish. Good corrosion resistance when used as undercoat. A number Of copper processes are available, each designed for a specific purpose. Brightness (to eliminate the need for buffing); High speed (for electroforming); Fine grain (to prevent case hardening); etc. Stress relief steel parts cold straightened or suspected of having residual tensile stresses having Rockwell hardness RC35 or higher will be subjected to 375° ±25°F-24 hours within 4 hours after plating. Parts with tensile strength over 120 Ksi bake 24 hours within 4 hours after plating.
| Type Class | Thickness (unless otherwise specified) | Comments |
| Class 0 | .001 - .005" | For heat treatment stop-off. |
| Class 1 | .001" | For carburizing and decarburizing shield, also plated through printed circuit boards. |
| Class 2 | .0005" | As an undercoat for nickel and other platings. |
| Class 3 | .0002" | To prevent basis metal migration into tin (prevents poisoning solderability). |
| Class 4 | .0001" |
Copper in color and matte to a very shiny finish. Good corrosion resistance when used as an undercoat. A number of copper processes are available, each designed for a specific purpose: Brightness (to eliminate the need for buffing), high speed (for electroforming), fine grain (to prevent case-hardened), etc. Copper plate is smooth, continuous, uniform in appearance, adherent to basis metal and not coarsely crystalline. Copper shall be free of pin holes, blister or other imperfections detrimental to usage of the plate. Steel parts having 40 HRC or above that have been heat-treated should be cleaned to remove surface contamination and stress relieved before preparation for plating.
55 HRC: Heated to not less than 275°F for not less than 5 hours before plating.
Other parts: Heated to not less than 375°F for not less than 4 hours before plating.
NOTE: unless otherwise specified, temperatures to which parts are heated shall be such that maximum stress relief is obtained without reducing hardness of parts below.
Procedure: Electrodeposited from suitable copper plating solution directly onto the meter/part. Corrosion-resistant and heat-resistant steel or alloys may require a preliminary strike of nickel or other suitable metal. Aluminum alloy may be stannate or zincate treated prior to plating.
| Type Class | Thickness (unless otherwise specified) | Comments |
| Class 2418 | .001 - .005" | ±0.0002" acceptable. |
| Class 2418-1 | .0001"-.0003 | |
| Class 2418-6 | .0006" -.0008 | |
| Class 2 | .002" | Under 0.0007" thickness not acceptable. |
| Copper Flash | .0001" |
