Hard Time

File: 082696_d50030_083.txt
Page: 083
Total Pages: 101
sauce) or through the~paint on the inside of your car door, where you cannot
see the corrosion until it blisters through the paint on the outside.    In the
desert, corrosion protection schemes face additional problems in wind and
sand, the combination of which can quickly leave a steel surface chemically
clean and totally unprotected.    As in any sandblasted surface, corrosion will
occur rapidly (sometimes in seconds) as soon,as the abrasive action stops.    If
the sand is salty. salt particles can be embedded in the surface, so that spe-
cialized cleaning is necessary prior to repainting.    It should be noted that
the hardest coatings are the most easily sandblasted, and softer coatings,
which are not easily chipped by flying sand particles, offer longer-lasting
protection.    Chemical agent resistant urethane coatings are hard~by nature,
and may be blasted off readily in a windstorm.    There are softer, rubbery
urethanes which have been used ror coatings (Baldwin guitars has such a coat-
ing in the mid 60's and they were of medium gloss and absolutely unchippable)
but whether these are resistant to chemical agents or decontaminants is un-
known.   Other coatings to consider are asphalt or r'ubber-based paints, again
probably not chemically agent resistant.
      If sandstorms or windstorms are predicted, equipment could be covered
with' tarps or other material to keep the surfaces from being blasted.   This
will be particularly important for glass surfaces because you can drive a ve-
hicle while the paint is off before it rusts to the point of unusability, but
if you can't see throu~h the windshield, you are stuck until it is replaced or
removed.
      In the case of repainting equipment which has been blasted by salty sand,
it is very important to get the surface clean before painting.    There is no
neutralizer for salt, but it is water soluble and steam cleaning with clear
water (no cleaner additive) will remove most of the slat particles, except
those which have been driven into crevices which are subsequently hammered
shut by continued blasting.     If enough water is available to do this, it is
probably the best slat-removal means.    In the aircraft industry, wet grit-
blasting or wet glass-bead blasting has been used to remove mixtures of rust
and salt from compressor airfoils, but this is an in-plant operation~and not
likely to be practicable in the field.    In any case, as soon as the surface
dries,  it should be repainted, and if noncontaminating means of hastening the
drying process are available (heat gun, alcohol spray, etc) it will further
aid in getting a durable paint job that will not rust from underneath.
      POGs are ~ill Taylor and George Downs,  Dugway Proving Ground, DSN 789-
3091/5649.

21.   Sand.   Apart from corrosion, sand is very abrasive and can be expected to
create problems in unprotected mechanical systems, of which track vehicles are
probably the prime example.    Lubricants tend to entrain the sand making it
into something like valve-grinding compound, which may accelerate wear more
rapidly than dry operation.    Low-pressure compressed air can be used to blow
sand from crevices,   shaft seals, etc. High pressure compressed air must be
avoided because it can blow sand particles under or through seals where they
either are held against a shaft by a seal lip, and act like a cutting tool, or
enter the lubricant system and are circulated by the oil.    In extreme cases,
they may also plug oil filters.
     A little ingenuity in recognizing sensitive areas of vehicles and
machinery will pay big dividends if field-expedient means of protection are
used,  i.e.  rags  tarps, tape, etc, when a sand storm is expected.  Low-cost
caulking materials may also be quick to apply to mechanical joints and rela.
tively easily removed afterward.    S(~ft materials (ltke caulking) must be re-


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