Painting Recommendations for Older Bins/Silos
After an extensive period of use, the question sometimes arises what kind of paint could be used to paint an older used bin or for the maintenance of a bin / silo that is in an aggressive environment. The following statement from our engineering archives addresses this point.Painting of galvanized grain bin shell components and roof panels.
Before painting, the steel surface should be free of all foreign materials such as dirt, white rust, red rust, oil, etc. Wire brushing or needle or brush blasting of corroded areas is recommended.
New, non-corroded galvanized steel will typically have a di-chromate (rust retardant) coating that inhibits paint adhesion. To paint new galvanized steel an abrasive removal process such as wire brushing or sand blasting will be necessary to abrade the di-chromate coating. Natural weathering will remove this coating as well. A minimum of six months would be required for the natural weathering off of the coating.
Once the steel surface has been cleaned, a zinc rich primer should be applied per the manufacturers instructions. Two coats of the zinc rich primer are normally recommended. This primer will have a dull gray appearance. To provide the bright shine and color of new galvanized steel a final coat of a rust inhibiting aluminum paint may be applied over the primer. One manufacturers primer product recommendation follows. Other manufactures may offer similar products.
For touching up small areas zinc rich spray paints marketed as "cold galvanizing compound" or similar identification may be useful. Check with your GSI Dealer for more information.
This is a non-epoxy product with good corrosion resistance, requiring a lesser degree of professional equipment or application than three component epoxy type paints. Contact the particular manufacturer for equivalent primers and aluminum paint numbers / specifications.Painting of commercial hopper tank steel columns and painted bracing
GSI commercial hopper tank columns are specially cleaned, primed and finish painted. For maintenance painting, the steel surface should be free of all foreign materials such as dirt, red rust, oil, etc. Wire brushing or needle or brush blasting of corroded areas is recommended. Check with your GSI Dealer for equivalent primers and paint numbers / specifications.