Aircraft Corrosion Protection, I
Aluminum corrodes almost immediately forming an oxide layer that will protect it from further corrosion. For example: Place an aircraft in a salty environment near the ocean and the unprotected aluminum corrodes if not handled or pretreated properly.
There are a number of ways one can protect an aircraft against corrosion: painting, waxing, zinc-chromate priming, thin layer of pure aluminum (Alclad), anodizing and coating with a liquid protective solution.
This article will discuss a product developed and used by Boeing on their aircraft as protection against corrosion. Is is very easy to apply and its capillary action makes sure every corner is reached, which is great for hinges on trim and servo tabs and the inside of wings, elevators, rudder etc etc.
Superior aircraft corrosion protection developed by the Boeing Company.
Unlike other Corrosion Inhibitors & Lubricants, Boeshield T-9 was developed by "The Boeing Companies Material Technology Laboratories" in order to meet the stringent applications required in the Aerospace Industry. Boeshield T-9 is effective because of its excellent Water Displacement, Penetration & Protective Film Development.
Boeshield T-9 was developed by The Boeing Co. for long term protection of aircraft. Their research proved that none of the Teflon, silicone, or synthetic sprays held up for long when exposed to a corrosive environment.
Developed by Boeing's Material Technology Laboratories, Boeshield T-9 is effective because of its excellent water displacement, penetration and protective film development. The resulting coating will outlast competitive treatments and exhibits excellent results in salt spray exposure, "EXCO" immersion, and dielectric current tests. Boeshield T-9 also meets all flammability requirements of Federal Aviation Regulation 25-32 after the solvents have evaporated, and is effective from -40° to 250°F.
The resulting coating will outlast competitive treatments and exhibits excellent results in salt spray exposure, "EXCO" immersion, and dielectric current tests. Boeshield T-9 also meets all flammability requirements of Federal Aviation Regulation 25-32 after the solvents have evaporated, and is effective from -40° to 250°F.
Boeshield T-9 has a mineral spirit base and can easily be sprayed with a variety of equipment. All that is necessary is enough pressure and nozzle size to form a consistent mist. Simply wet the surface and the desired coating will form after 5 to 7 days of drying. Excessive spraying will only increase puddling and extend drying time.
As for equipment, many owners have successfully applied Boeshield T-9 using a garden sprayer which usually comes with a 12" to 18" wand, adjustable nozzle, and is hand pump pressurized. With a little experimentation, the proper combination of aperture and pressure for maximum atomization can easily be determined. The product is then reapplied when necessary during the annual when inspection covers are removed.
For commercial application, a more sophisticated spraying system can be used, and many FBO's have such equipment. Their main advantage is the ability to move liquid through longer wands and achieve better coverage of hidden surfaces, particularly inside wings when working from the tips. Since most of the treatments currently used have similar viscosities, the delivery system need not change. All that is required is to wet all interior surfaces. Access to key corrosion producing areas is more important than the application method.
As for the quantity required, one gallon of liquid is more than enough to completely coat the interior wings, fuselage, tail, and control surfaces of a typical single engine aircraft.
Once on the surface, Boeshield T-9 has excellent penetrating and moisture displacing properties. Through capillary action it will cut through and stop existing corrosion, find its way into lap joints, seams, and around rivets, and eventually weep out the exterior. However, this activity stops after a limited time (usually 5 to 7 days, depending on temperature and humidity) at which point a waxy film develops in all areas. In this way, the coating will stay put for much longer than the all liquid treatments, eliminating the continual weepage and cosmetic problems associated with them.
When reapplication is necessary (usually 3-5 years depending on service and exposure) the existing coating will be reliquefied and resume its penetration and weepage, again only for a limited period.
Boeshield T-9 also is nonconducive and will not cause short circuits in electrical systems. However, care must be taken to keep away from areas where point contact is required, such as keypads on electronics.
As mentioned previously, Boeshield T-9 has a mineral spirit base and contains no harsh solvents such as MEK or Trichlorid Ethylene. Therefore, it is safe to use around most paints, plastics, rubber, vinyls, wiring, and many glues. It is very effective for rust proofing steel tubing on fabric covered aircraft, but should be tested on the exterior skin prior to application to insure no degradation of the material or lap joints takes place.
Text from the website of Boeshield.