Steel that is to remain unpainted need only be cleaned of heavy deposits of oil and grease by appropriate means after fabrication. If other considerations dictate more stringent cleaning requirements, an SSPC-SP2 or other appropriate grade of cleaning should be specified in the contract documents.

last modified 18 September 2002

As indicated in the AISC Code of Standard Practice Section 6.5.2, in the absence of other requirements in the contract documents, the fabricator hand cleans the steel of loose rust, loose mill scale, dirt, and other foreign matter, prior to painting, by means of wire brushing or by other methods elected by the fabricator, to meet the requirements of SSPC-SP2 (hand tool cleaning).

Yes, unless prohibited in the contract documents.

last modified 18 September 2002

When blast-cleaned surfaces are specified in contract documents without identification of the desired degree of cleaning, SSPC-SP6 (commercial blast cleaning) is assumed.

last modified 18 September 2002

The acceptance criteria for the degree of preparation are specified in SSPC-VIS-1, The Pictorial Surface Preparation Standards for Painting Steel Surfaces, for all SSPC surface preparation levels (SP1 through SP10).

last modified 18 September 2002

When blast profile limits are specified, a Keane-Tator profile comparator, or equivalent, is acceptable for spot checking representative production blasting. Note that the specified profile range must be evaluated relative to the profile of the steel prior to blasting. Therefore, the total profile range will usually be greater than the range specified.

last modified 18 September 2002

When inspection is required in the contract documents, it should be made as soon as practical after the surface has been prepared. Inspection should be scheduled to avoid delays in the fabrication shop. Additionally, because the adequacy of surface preparation cannot be readily verified after painting, it should be inspected prior to application of the primer coat.

last modified 18 September 2002

Generally none, however, because a wet paint film is drawn by surface tension to a lesser thickness over sharp edges, some paint system specifications for severe exposures call for special edge treatments, such as grinding a light chamfer on sharp edges, striping corners or edges with shop paint to increase film thickness, or grinding corners to a minimum 1/16 in. radius. It should be noted that the term radius has precise meaning and an attempt is sometimes needlessly made to check corners with a radius template and require repairs at corners that do not conform closely to the specified radius. Because there is no significant difference in paint film thickness or life between a beveled corner and a corner that is ground to a small radius such treatment of edges is discouraged unless specified in the bid documents or in the paint manufacturer's directions. When required, edge treatment requirements should be limited to "breaking" the corner (eliminate the sharp 90° edge) with no reference to a specific dimension.

last modified 18 September 2002