<VV> Cleaning the engine (Teardown III)

[Tony Underwood]

At 09:44 hours 06/23/2006, AeroNed at aol.com wrote:
>
>In a message dated 6/23/2006 3:12:59 P.M. Central Daylight Time,
>contactsmu at sbcglobal.net writes:
>
>I then  sprayed them with
>Purple Power grease remover and brushed them  again.
>
>
>Stephen,
>
>Be careful using degreasers. Many of them are not recommended for aluminum,
>including Purple Power, I think.
>
>A cold tank contains powerful degreasing fluid, sort of like carb  cleaner.
>The tank is very large to accommodate very large parts. The parts are  soaked
>for a long period of time to break down all the grease. Then they are  rinsed
>and dried, sometimes with compressed air. The other common method is a  hot
>tank, which contains a heated solution.
>




"Hot tank" cleaning uses sodium hydroxide to break down grease and 
convert it into a water soluble compound (basically soap) which 
washes off easily and takes dirt with it.    Trouble is, sodium 
hydroxide is pretty mean stuff especially when concentrated in hot 
water.   It will strip grease, paint, your skin, etc.   It also 
dissolves aluminum like cake icing.   Be careful with aluminum and 
hot tanking.   They don't play well together.   Works great for 
degreasing cast iron and steel, however.   Leaves it bone dry 
clean.    In fact, it's so clean it rusts almost immediately at the 
first hint of humidity unless a light oil is sprayed onto the work 
after drying.

The trick for cleaning aluminum is to make friends with someone who 
works at an automatic transmission service center.   They have vats 
with aluminum-safe solvents in them to soak transmission cases.   You 
could have your buddy slip the 'Vair engine parts into the soak vat 
overnight for you, maybe slip him a few bucks etc.  ;)

Bare aluminum with no ferric metal components like studs or plugs or 
inserts etc can be further cleaned and "de-oxided" with a nitric acid 
bath if you want the aluminum clean enough to qualify as operating 
room sterile.    The acid bath is a normal step in cleaning aluminum 
before anodizing.    It's mostly to remove any aluminum oxide which 
may have resulted from corrosion along the way.    Nitric acid is 
extremely rough on ferrous metals and organic materials, to the point 
that it's close to horror movie destructive on skin.   Your hide 
turns yellow, then green, then sloughs off in sheets like crumbling 
cardboard.   Don't do it.   Too bad it's as nasty as it is because 
it's a *great* aluminum conditioner, brightens it right up.   In 
fact, it's sometimes called "brite-dip" treatment.

Interestingly enough, nitric acid treats iron/steel the same way 
sodium hydroxide treats aluminum.   But they're both 
dangerous.   Watch your fingers.

Then again, carb cleaner works pretty well for both iron and aluminum 
and it's not likely to remove your hide.   Advance stores sell the 
stuff cheap and it even has a light oil in it to keep the parts from 
oxidizing or rusting afterwards.


tony..