We went into one of the major paint companies and did a demo with both waterborne and solvent.  We found that with solvent on a black basecoat keeping the humidity level very low made a big difference. Most desiccant units have an indicator paper that changes color when the moisture is over 10%.  We tested at 14% humidity, which is really when most of those papers change. Our PERF system yielded 0% percent humidity. We found that the panel with 0% humidity was 10 minutes faster flash time in the solvent-based. With waterborne, without added airflow, we found that it was 15 minutes faster flash time without having to blow extra air over the panel.
    We do an average of 36 audits a week, (with 41 reps nationwide) and we find the average percentage of humidity in the body shop is from 30 to 40%.  When you add that to the equation of between 14 and 0% it makes a big difference in production.

    I have a high production shop who put in one of our PERF 25 units who told me he gets one more car per booth now.
    Many of the shops in California are busy changing paint and systems at the same time. If they spend the money for a PERF 25 unit the paint performs much better. It’s just physics. If you have 0% humidity in your air you’re pulling a lot of the water off the surface in your spraying.  At 70° you can have 73% humidity in the air.  If you start with 0% that’s a lot more water that can be picked off the surface. Whether using handhelds or not, keeping your air at 0% humidy makes everything perform much better. I think you find with waterborne you can’t do things the way you used to do them.  You’re going to need some investment. The number one investment that you have to have is a compressor big enough for adequate air volume and something to clean and dry the air.  
    We are basically recommending screw compressors for two reasons. First, the duty cycle on a piston compressor is shorter, and piston compressors create much more heat and oil vapor. They actually will not last as long. The piston compressors give you between 180° to 200° air coming out, whereas  a screw compressor, even without after coolers, comes out about 120° and that itself lowers the humidity content. The lower the temperature, the less moisture the air can hold.

With the PERF air units a refrigerant dryer is not necessary because the unit dries it very well. But a refrigerant unit might be useful for the rest of the shop.
    Our recommendation is to replace the desiccant every three years and if they have a refrigerant dryer it would be every five years. We give a written guarantee for three years. Our suggested price is $2199 for a PERF 25 and $2699 for a PERF 50.  You might want to look at a PERF 50 if you’re using four to six air blowers.
    With the two filters prior to the desiccant, replacement is once a year on the first stage and every six months on the coalescing filter. For the post-filter it’s every six months. If the shop air audit shows a lot of oil contamination it does need to be replaced more often. I would check them monthly and maybe plan a quarterly replacement in the prefilters.
    We do a free air audit anywhere in the United States by one of our trained representatives like Sean Martinez. They provide a three-part form which gives you a written report on your system. Problems we find are pipe scale and rust coming through the line and we also find a lot of desiccant breakdown if they’re using other products.  

RTI can be contacted at 800-521-9200, or www.rti-pbe.com. Sean Martinez can be contacted via email at This e-mail address is being protected from spam bots, you need JavaScript enabled to view it See RTI’s ad on PP39.