- 1). Remove the loose, flaking paint with a wire brush. The loose paint will need to be removed before sand blasting can occur. Gently brush away all loose paint with a large- or medium-sized brush. Place a plastic drop cloth below the trusses in order to catch the paint debris.
- 2). Remove the remainder of the paint using an abrasive blaster. You can rent or purchase a portable abrasive blaster at any tool rental store or hardware store. Load the blaster with sand or walnut shells. However, make sure that the blasting medium is used for abrasive blasting. Some sands are too wet and not appropriate for loading into the blaster. Pay special attention to the small cracks of the steel trusses when blasting, and allow the blasting nozzle to remain on the cracks for an extended period in order to completely clean the paint away. The metal should turn bright silver when it has been thoroughly cleaned.
- 3). Clean the metal using paint thinner or acetone. Dampen a cloth rag with the cleaner and wipe away all sand or other dust debris from the metal. Allow the metal to dry for one hour before proceeding.
- 4). Spray on two coats of metal primer and allow a 30-minute drying time between each coat. Use spray cans or an electric spray applicator to apply the primer. If using a spray applicator, mix the primer well before adding to the spray container. Make sure you cover the small, hidden areas of the metal.
- 5). Spray on two coats of finish metal paint, allowing 30 minutes of drying time between each coat. The finish paint can be applied in the same way as the primer. However, the finish paint can be satin, semi-gloss and gloss. If your trusses are outside, and therefore exposed to the elements, make sure you apply exterior metal paint.
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