Pretreating parts may be easier than spraying powder, but good pretreatment technique is still very important. Without it, parts won’t get clean – or, worse yet, a careless operator could cause premature rust or permanent damage.
Pretreatment operators, remember the three Ps: pressure, pattern, and passes.
Pressure is largely determined by the equipment that you’re using, but a good operator knows how to compensate. If you’re pretreating small parts with a pressure washer, for instance, you run the risk of blowing them around and causing damage…unless you’ve secured the parts and are standing far enough away. The goal is to walk the fine line between applying enough pressure to clean parts efficiently, while avoiding damaging them in the process.
Chemicals act on the substrate. That’s the whole point of pretreatment. The goal is to pretreat every square inch of the part as evenly as possible. Plan your pretreatment patterns so you don’t miss any areas or hit the same area multiple times. Keep in mind how the chemical will run across the part during the pretreatment process.
Once you’ve planned your pattern, it’s time to determine how many passes – or iterations of that pattern – you’ll do. This will mostly depend on the part’s dirtiness. A seasoned operator will notice if the part isn’t getting clean enough (or if the conversion coating isn’t building fast enough), and will add passes accordingly.
Like most skills in our industry, good pretreatment technique comes with experience. But by paying attention to the three Ps, you’ll minimize the chances of operator error in the wash bay. Learn more here.