WIRE PREPARATION
CHEMICAL STRIPPING
two conductors, one stripped, the other in the process of being chemically stripped
CHEMICAL STRIPPING

Chemical stripping of organic insulation from solid conductors is an alternative to mechanical stripping, especially on small gauge (< 28 ga.) conductors. The process is an efficient method to use for complete removal of the insulation, resulting in an exposed, clean, solderable conductor surface.

Chemical stripper agents range in degrees of aggressiveness, towards both the insulation material and the conductor metallization.

See Section 1.01 "Wire Preparation, General Requirements", for common accept/reject criteria.
conductor with insulation jacket removed conductor with stripped insulation with a red mark on it denoting inappropriate conductor types should not be chemically stripped

PREFERRED

The insulation jacket has been neatly removed, with no damage to the conductor or insulation. No wicking of stripper or cleaner agents under the insulation jacket is evident.

Note: Chemical stripping is suitable for solid conductors only.

UNACCEPTABLE

INAPPROPRIATE CONDUCTOR TYPES

Chemical stripping of other than solid, single-conductor wire (i.e.: coaxial cable, flat cable, multi-conductor cable, ribbon cable, shielded, stranded, etc.) is prohibited.

Best Workmanship Practice
acceptable edge flash at edge of insulation stripping unacceptable edge flash at edge of insulation stripping

ACCEPTABLE

EDGE FLASH/SMEARING

Edge flash shall not exceed one-quarter insulated wire diameter (1/4 d.). Edge flash and smearing (as depicted) is considered normal, and should not contaminate or interfere with crimped or soldered termination.

NASA-STD-8739.4 [10.1.6]

UNACCEPTABLE

EDGE FLASH/SMEARING

The edge flash is in excess of one-quarter insulated wire diameter (1/4 d.), and the stripped section exhibits smearing (melted insulation/film), which is considered a contaminant.

NASA-STD-8739.4 [10.1.6]
NASA WORKMANSHIP STANDARDS
NASA logo Released:
03.31.2000 		Revision:
B 		Revision Date:
07.03.2002
Book:
1 		Section:
1.04		 Page:
1




WIRE PREPARATION
CHEMICAL STRIPPING (cont.)
conductor with scuffed insulation conductor with damaged insulation

ACCEPTABLE

SCUFFED INSULATION/JACKET

Slight scuffing (a dull or rubbed appearance) of the insulation surface finish is acceptable, provided no other damage is evident.

NASA-STD-8739.3 [7.2.2]
NASA-STD-8739.4 [10.1.2]

UNACCEPTABLE

DAMAGED INSULATION/JACKET

The conductor insulation and/or cable jacket shall not exhibit any damage, such as nicks, cuts or charring. Conductors/Jackets exhibiting damage (other than minor scuffing) shall not be used.

NASA-STD-8739.3 [13.6.2.a.1]
NASA-STD-8739.4 [19.6.2.a.2]
conductor with burns and corrosion on the surface wicking of insulation

UNACCEPTABLE

BURNS/CORROSION/PITTING

Burns, corrosion and pitting are typically caused by the use of an extremely aggressive or chemically incompatible stripping agent, or excessive exposure.

NASA-STD-8739.3 [13.6.2.a.7]
NASA-STD-8739.4 [19.6.2.a.2]

UNACCEPTABLE

WICKING

Wicking of chemical stripping and/or cleaning agents under the insulation jacket is a long-term reliability concern.

NASA-STD-8739.3 [13.6.2.a.9]












NASA WORKMANSHIP STANDARDS
NASA logo Released:
03.31.2000 		Revision:
B 		Revision Date:
07.03.2002
Book:
1 		Section:
1.04		 Page:
2


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