Application Note 36 - Aircraft Connectors with Fluorosilicone Inserts

Application Note 36 - Aircraft Connectors with Fluorosilicone Inserts

How should Stabilants be used on connectors with fluorosilicone water-barrier inserts?
In many aircraft connectors, a fluorosilicone washer is used at the base of the male pins to form a barrier, which when compressed by the screwing-closed of the connector, acts to form a water-exclusion barrier between the pins thus reducing both signal leakage and increasing flash-over voltages.

As most solvents cause swelling of this elastomer, a connector which is "sealed" in the barrier-swelled condition, might leak once the solvent dissipates and the elastomer shrinks. While the 6% swell caused by the 80% isopropanol diluted Stabilant 22A will go away once the solvent evaporates, many service engineers are working on tight time schedule and the potential exists for premature closure of the connector.

To avoid this situation, testing was done to determine a level of isopropanol dilution which would not cause a swelling problem. It was determined that a 7% by volume dilution was satisfactory. This can be achieved by adding 7 parts by volume of isopropanol (98% isopropyl alcohol) to 100 parts of Stabilant 22 concentrate. There is sufficient air-space in the bottles to permit this, but the bottle should be labelled as containing 7% isopropanol.

Alternately, we can, on special order only, supply a 7% isopropanol-diluted material under the designation Stabilant 22P. The MSDS's for Stabilant 22 & 22A will cover this material.

Revision 3

Stabilants™ are a product of Dayton Wright research & development and are made in Canada

NATO Supply Code 38948
15 ml of S22A has NATO Part # 5999-21-900-6937