removing HEAVY chalking from metal/alum siding.

[IWPsteve 14]

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

[AquaMike 36]

I've two stepped a few houses for painters before with good results. Not something I'd recommend if you don't know how to do it as you could damage things. Hire someone who knows how to do it and you shouldn't have an issue.