*This message was transferred with a trial version of CommuniGate(tm) Pro*
Howdy List,
Concerning the salt problem when using sand as a blast medium, it is
well worth ones time to call a local commercial blaster and ask them
where they get their medium. If they do not use the brand name 'Black
Beauty' they can still guide you to a local source for clean, dry,
uniform grade silicone free medium.
There is a salt removing prewash which shipyards use just prior to
putting on the first coat of primer BUT they use Black Beauty, or its
equivalent, to make sure that they do not embed salt in the micro
crevices of the metal created by the impact of the blast medium while it
is removing the rust and paint. They use the prewash because large yards
are usually next to large bodies of salty water where the mere wind
blows enough salt air to contaminate a surface within a couple of hours.
Once you have imbedded the salt in the metal it is virtually impossible
to get it all out without submerging the part and boiling it. After you
go to all the trouble of boiling your parts, dealing with the rust bloom
that that creates you would be money and time ahead to get good medium
and be ready to prime the part(s) within one hour or less.
Sand is OK for cleaning wood or concrete, but you should try really hard
to get a pallet of the good stuff.
Happy Blasting!
Mel Miller
M725
McCain for President!
This archive was generated by hypermail 2b29 : Thu Mar 02 2000 - 22:30:41 PST