How should I prep old aluminium cladding before painting? What type of primer is the best for cladding?
Answer Remove as much “chalk”, dirt and mildew as you can. This is done by power washing or by scrubbing and rinsing. The only times a primer would be needed are: 1) if any bare aluminium is exposed; then use a acrylic corrosion-inhibitive primer; 2) if there is still much “chalk” left on the surface, apply a quality exterior alkyd (“oil-based”) primer recommended for aluminium cladding by the manufacturer. (“Chalk” is powdery pigment on the surfaced of the weathered cladding, that comes off when you rub the palm of your hand over the surface.) Question After removing the old chalky white from aluminium cladding, I was told to wipe the cladding with mineral spirits before priming it. Is this a necessary step before washing it? I had to use a sander to remove the road salt and the cladding was badly pitted. Answer No, unless you have some oily contaminant such as road tar on the cladding, do not use mineral spirits. The road salt that you removed was probably white aluminium corrosion (