Posted on the rec.bicycles.tech newsgroup today about the use of Simple
Green on aluminum parts:
> Aircraft Cleaners
>
> Simple Green and other cleaners that are not listed in the
> Technical Manuals are taboo for a very good reason - they
> hurt the metal used to build the machine.
>
> It has been brought to the attention of the U.S. Army
> Aviation Missile Command (AMCOM) Depot Maintenance
> Engineering Team that numerous units are using the
> commercial product SIMPLE GREEN as an aircraft wash.
> STOP! This product has been through Department of Defense
> (DOD) testing and was determined to be highly corrosive
> on aircraft aluminum and also a catalyst for Hydrogen
> Embrittlement in high strength aircraft alloys.
>
> While a highly effective cleaning agent for floors and
> non-aluminum / non-high strength alloy vehicles this
> product is not approved for aviation usage. If your unit
> has been using SIMPLE GREEN on a regular basis, it is
> recommended that a thorough fresh water wash with the
> approved cleaners per the appropriate airframe maintenance
> manuals be accomplished as soon as practicable. This
> should be followed up with a corrosion inspection /
> treatment and application of approved Corrosion
> Prevention Compounds (CPCs).
>
> Mr. Richard Cardinale, corrosion@amcom-cc.army.mil
> (361)961-4041, DSN 861-4041
>
> http://safety.army.mil/
> ============================
>
> AOPA advised caution with any cleaner and stated that "No
> cleaner should be left on an aircraft for an extended
> period; any cleaner should be promptly and thoroughly
> rinsed off the airframe with water."
>
> It's Simple -- Don't Use This To Clean Aluminum
>
> A well-known aviation magazine this month published a
> feature article on cleaning one's aircraft and getting
> it ready for spring flying. Only one problem -- a product
> the article recommended as safe for aviation use has been
> proven corrosive to aluminum. The product is Simple Green,
> a popular household cleaning liquid. According to the
> magazine's May issue -- which included a photo of Simple
> Green and other products -- the liquid "does an admirable
> job for a fraction of the cost of the aviation cleaners."
> While that may be true as far as it goes, both the U.S.
> Air Force and the U.S. Army have conducted tests of Simple
> Green and strongly urge that it not be used to clean
> aluminum structures. In one test conducted by the U.S.
> Air Force, results from which were published in 1989,
> aluminum alloy samples were immersed in Simple Green for
> a week then removed, cleaned and weighed. The results
> indicated that the approximately 3.5-gram aluminum alloy
> samples experienced a material loss of about 31 milligrams
> in a diluted solution and a whopping 295 milligram loss
> after spending a week in the undiluted liquid. The Air
> Force report summed it up this way: "We do not recommend
> the use of this product on Air Force equipment containing
> aluminum." a