PROBLEM
McDonnell Douglas Space Systems Company was faced with a tough requirement regarding emission of volatile organic compound (V.O.C). The Environmental Protection Agency’s Rule 24 went into effect in 1990. It restricts V.O.C. values of chemical products used in processing to the maximum of 330 grams per liter (GPL). The current solvent rust inhibitor supplied by Castrol did not meet the V.O.C. regulations, making it imperative for the companies operating in the Southern California region to search for substitutes. In addition to low V.O.C. values, the replacement had to meet the following requirements:
1. Excellent corrosion inhibiting properties on aluminum.
2. Removability with alkaline cleaners.
3. Thixotropic properties.
4. Sprayable with high-volume/lowpressure spray equipment.
APPLICATION
McDonnell Douglas applied VpCI®-369 in a 1:3 dilution with low-pressure/high–volume sprayers. VpCI®-369 produced a thixotropic, uniform film on the aluminum skin surfaces, which prevented the pooling effect that was a problem with McDonnell’s previous product. It also was removed easily using standard alkaline cleaner, Douglas’ DPM 980 at 160° F (71° C). The break-away occurred in less than 10 seconds for VpCI®-369 diluted 1:3. This was true for all film thicknesses ranging between 0.5-2 mils (10-50 microns).
CONCLUSION
The finished result was that corrosion was removed and parts were suitable for assembly, with added temporary rust protection.
PRODUCTS
