Debasis ISO 8504: 1992(E) / SSPC SP 10 or SSPC SP 6 Both specifications are near equivalent to Swedish Standard -SIS 05 59 00) - whichever standard followed by you at your plant. SIS 05 59 00 gives pictorial standards . ISO 8501-1:1988 (E) gives information on visual assessment of surface cleanliness. The surface profile obtained during blasting is important and will depend on the abrasive used, the air pressure and the technique of blasting. Guidelines on Type of Abrasive, Mesh size, Max Height of Profile are available in these standards. Typical roughness profiles obtained using various types of abrasives should be as follows : Abrasive Type Mesh Size Max Height of Profile Very Fine Sand 80 size 37 Microns (1.5 Mils) Coarse Sand 12 size 70 microns (2.8 Mils) Too low a profile may not provide sufficient key or anchorage for coating. Too high a profile may result in uneven coverage with high and sharp peaks leading to premature coating failure. I guess that your paint and blast specification should more or less follow the above profile for sand-blast cleaning to Sa 2.5 finish, depending on the type of sand used in your plant, air pressure, technique used for blasting, Surface profile acceptability for both Inorganic Zinc Silicate / H.R Silicone Aluminium by Spray should be nearly the same - minimum or maximum anchorage will not alter if this acceptability pattern is followed ( I guess). The key is the surface profile obtained within the range specified as above - based on the above factors and selection of sand quality, air pressure and technique used by the applicator for the job. I guess there will be no big difference between application for inorganic zinc silicate or H.R silicone based Al paint . Minmmum or Maximum surface finish will not basically alter if these factors are taken while blast cleaning. Trust this is of help to you C.V.Srinivasan Nishi Engineers Pvt Ltd India Aug 6, 2005 E-mail:nishi@vsnl.com >Sand Blast Clean surface will generate a visual appearance >and a surface anchor profile depending upon the initial >surface condition. For Sa 2.5 surface what is the minimum >and maximum surface surface profile acceptable for painting >for Inorganic Zinc Silicate by Spray and HR silicone based >Aluminium by Spray ?