We are a painting company, so our cleaning doesn't have to look good (ie-streaks, etc are okay), it just has to provide a good clean surface for paint adhesion. We PW aluminum houses and metal sided buildings every day. We currently use TSP and 12% SH downstreamed from an 8 GPM cold water machine. On heavily oxidized siding and gutters, we normally have to hand scrub along with the wash to get the chalking completely off. The test is a clean hand aggressively rubbing the surface, if any chalk still comes off it's not good enough.
We are looking for a chemical that we can spray on or ds/xjet on, let sit, wash and be done. We do miles and miles of washing, and the labor of hand scrubbing is killing us. Any suggestions?
Thanks,
Steve