I noticed your response to the first question in the January 2001 issue of Products Finishing. For many years we have supplied our corncob grit to contractors who clean and paint transformers. They soft grit blast clean the transformers with our product and then clean off any airborne residue before painting. Since this material is 100% organic and non-sparking, it seems to be the media of choice. T.W.
For the record, in the January Painting Clinic D.N. was approached by a local EMC to submit a bid to inspect and repaint (as necessary and in a field environment) the on-pad transformers as part of a 5-year cycle of preventive maintenance. He assumed they would need to be sanded, primed and then repainted. He was concerned about using the correct primer, paint, application procedures and any other special considerations. In my answer I stated the following procedure:
- Clean the surface to remove oily soils and particulates.
- Sand as needed to remove corrosion products.
- Remove sanding residues.
- Prime coat the affected areas.
- Topcoat the entire unit.
He wanted sanding, so I gave him sanding. I guess I could have told him to buy a portable blast cleaner and your corncob blast media. You must remember that folks like me from Dunbar, PA, use corncobs to make smoking pipes and to hang in the outhouse. However, you are right, blast cleaning in an excellent choice for in-the-field repainting, and corncob media is environmentally friendly.