“Gentlemen, Some time ago I read an article by Nick Liberto that mentioned the possibility of ‘water quenching’ for cooldown after the bake/cure process. Where can I find some info./sources for this? It seems like it would be much faster than a forced cool air cooloff tunnel. I’d like to bring the parts down to near ambient as fast as possible to maximize throughput. Would the ‘misting’ leave water spots and or salt deposits?”
“Also, again with maximum throughput in mind is it possible to powder paint parts that are around 225deg. F (i.e. after they come out of pretreat-dryoff? My powder supplier recommends a part temp. no greater than 125-130deg. prior to paint application. We will be using a ‘hybrid’ black with low gloss/flat finish. Any help would be appreciated.”
“For the record, my name is Nick Liberto and I’m president of Powder Coating Consultants.”
“When I wrote that article, I was referring to custom designed water quenching equipment. Most system houses in our industry will be happy to quote you one. This method is certainly faster than forced air cool-down, but has some associated risks. For instance, water spots are a problem. However, these can be dealt with by treating the cooling water prior to spraying. There are sheeting agents, softeners, etc. that can be employed to correct this problem.
As far as the proper part temperature for powder coating, your powder supplier is correct in stating that the temperature should be between 125-130 degrees F. Hotter parts will tend to have higher film builds and may begin melting (or sintering) the powder as it is applied. Both of these issues can affect appearance and fit of the coated part. But if they don’t, then have at it. Good luck!”