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.

Ask an Expert

We are here to help, just ask! Our experts will help determine the best solution for your needs.

Newsletter Signup

Get the latest insights from NTS!