MIL-STD-1130 Connections, Electrical, Solderless WrappedThis standard establishes the requirements to produce mechanically and electrically stable, solderless wrapped, electrical connections made with single, solid, round wire and appropriately designed wrapposts terminals.This standard includes:a. Classes and requirements for solderless wrapped connections. b. Description and requirements for the wire used in making the solderless wrapped connections. c. Description and requirements for the wrappost used in making the solderless wrapped connections.

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MIL-STD-1130C

5.6.2 Gas tight. 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.

a. 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.

b. 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.

c. 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.

5.6.3 Unwrap test. Wire on wrappost shall be capable of being unwrapped without conductor breakage. (See figures 14 and 15).

5.6.3.1 Unwrap test (conductor brittleness). Place the unwrapping tool over the terminal post and engage its leading edge between the wrap end and the next wrap turn. Rotate the unwrapping tool until all the wire has been transferred onto the tool. Remove the tool with the loose helical coil from the terminal post. Holding the insulated portion of the wire firmly, rotate the tool unwinding the wire. The unwrapped wire need not be perfectly straight; waves and permanent deformation in it are permissible.

FIGURE 14. Unwrap test procedure A (see 5.6.3).