Gas Tight and Wrapper Resistance

Gas Tight

When tested in accordance with MIL-STD-1130, seventy-five percent of the corners in contact with uninsulated wire, except for the first and last turn, shall be gas tight when tested as follows:

Darken the assembly with ammonium sulphide gas after wrappost is exposed to aqua regia fumes.

  • The wrappost shall be suspended and corked in a 16 x 150 millimeter (mm) test tube containing approximately 1 to 2 milliliters (ml) of aqua regia solution (1:1 concentrated hydrochloric and nitric acids).
  • The solution must not touch the wrappost assemblies. The wrappost assemblies shall be exposed to the aqua regia fumes for 10 minutes.
  • The chemically attached wrappost shall be transferred to another 16 x 150 mm test tube containing approximately 1 ml of concentrated ammonium sulphide solution.
  • Suspend the wrappost connections in the test tube so that they will not touch the ammonium sulphide solution. Close the test tube with a cork or rubber stopper and leave the specimens exposed to this atmosphere until they turn dark. Copper and gold sulphide color will be developed on all areas exposed to vapor.
  • Dry and unwrap the connections with a tool which does not scratch the post. The gastight areas will appear in bright, sharp contrast with discolored area.

Wrapper Resistance

When measured in accordance with MIL-STD-1130; Table V, the voltage drop across the wrapped connection shall not exceed 4 millivolts.

The pin shall incorporate a compliant staking area providing mechanical stability of the , accordance with MIL-STD-1130. The tip of the wrappost shall be beveled to facilitate insertion onto the bit, Force The force to strip a wrapped connection conforming to MILSTD-1130 from the wrappost shall be not, discolored pin surface, The test shall be in accordance with MIL-STD-1130 Quality assurance Provisions.


  • The stripping jaw shall engage at right angles to axis of the wrappost.
  • When the wrappost and stripping fixture are properly aligned, the clearance shall be such that there is no binding or wedging between jaw and wrapper.
  • Both sides of the stripping jaw shall be in the same plane, creating a flat surface contact with the wire on either side of the wrappost.
  • On a rectangular post, the jaws of the hook shall engage along the major dimension (cross section) of the terminal. The maximum total clearance between jaw and terminal shall not exceed 0.7 x diameter of the wire. The minimum clearance, when the terminal and stripping tool are properly aligned, shall be such that there is no binding between jaw and terminal.