Christopher-
 
The SSPC (was the Steel Structure Painting Council, now Society for  
Protective Coatings provides guidance/guidelines for surface preparation  (SP) levels 
which vary according to the material to be coated and the  coating material. 
Check out their website.
 
Twybil

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To terminate puerile preservation prattling among pals and the
uncoffee-ed, or to change your settings, go to:
<http://listserv.icors.org/archives/bullamanka-pinheads.html>