As I said in my last post, my friend Dave and I had an ah-ha moment when we realized that new coatings technology probably means that we need to approach how we build things as well as how we spray things in the booth.
He was spraying a project that amounted to a group of flat slabs connected yet held off from each other by dowels. There was a ½-inch space between each slab. That required all six sides of each slab be finished. He was having trouble spraying those edges and the faces while balancing the extremes of runs and dry spray.
His booth, as I said, gets warm on hot days. His makeup air comes straight off the roof. He also has a really effective fan in his stack that moves a lot of air through the booth. All of that isn’t much of an issue with solvent-based coatings. He simply adds some retarder to adjust his open time as the booth temperature rises.
But this is new technology. You can’t do that with water borne coatings because retarders are almost nonexistent. The coating dries like it dries and it dries by water evaporation. But changing air temperature being moved by a constant air flow makes the water evaporate at changing rates.
So how does a shop deal with this? I really encourage builders to build as if they were the finisher. Make adjustments at the bench before the project hits the spray booth. I’m all for work at the bench that will allow for easily spraying the project and getting it back out of the booth.
The classic example of this is not attaching the cabinet back to a cabinet with a finished interior until the cabinet and the back are sprayed. This approach gets rid of the frustrations of spraying inside corners and box interiors that are so hard to spray. Leaving the back detached rids the finisher of having to deal with the turbulence that blows overspray everywhere that you don’t want it to be…including back in the finisher’s face. No runs, no drips, and no errors!
In retrospect, it would have been easier to spray those flat slabs separately as opposed to attached as an assembly. There was no compelling reason to assemble the whole unit until after it had been sprayed. Was there? If the builder can build a bit more like he’s the finisher then projects can go through the shop in such a way that we avoid excess hours or, heaven forbid, having to redo things due to the lack of our ability to spray them easily and quickly.
I am making a case here for the fact that the builder and the spray guy need to be in each other’s pocket. Yet, how many times have I heard or have you said, “We don’t do it that way here.” Might I suggest that you consider alternative ways of thinking and spraying outside the box???
Until next time…spray on!
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