It was approximately 1995 – The new building was of block construction, was a rental, and although situated in an industrial area, had neighboring businesses to consider. These are common hurtles that often have to be overcome when building a sandblast booth in a commercial setting. There were also genuine construction issues to solve… what we came up with was not ideal – but it DID work … well sorta.
It was a fun one to build – the boss was willing to put some money into it and we had given it’s design a great deal of thought. We agreed that air needed to be pulled FROM it, but how could we do this without cutting a hole through the block exterior?The solution was that we built it in front of the backdoor, and used the door as the place for the exhaust. The first consideration was maintaining the functionality of the door for security and other obvious practical reasons. The complicating factor though was that we didn’t really want to lose valuable working space inside by building the exhaust device into the interior of the booth.
What I ended up making looked sort of like a wheel barrel in the shape of a refrigerator. The top half of the beast was a large swamp cooler (squirrel cage fan) and the bottom half was a filtered dust collection chamber. I attached a couple of ergonomically placed fold-down handles recessed into its front that I could pull up to use to roll it into place into the door opening. It was of course NOT light-weight and was more than a bit awkward – but it really only took 2-5 seconds to get it into place, and I was operational for the day.
I have no photos of the contraption, but I remember it very well. In taking this trip down memory lane I was surprised when I mentally reviewed the way it was designed and how it had performed. It’s embarrassing really – I had gotten so far as to realize that air should be sucked from the booth, then turned right around and decided to BLOW it into a filtered box! I’m sorry but this was again wrong. I cant remember this specifically, but I’ll bet those filters puffed out far enough that escape holes opened up. Either that or they just blew right off and maybe we forgot to ever put them back on. Again, not knowing any better at the time, we thought it worked great.
My favorite thing about booth#3 was the load-in door. The structure being situated as it was, next to where we parked the company truck, there would have been a conflict in creating any kind of swinging door, so the boss located some heavy-duty track hardware and I made one big huge hanging/rolling door. It was extremely cool.
When pulling air through a sandblast booth, one thing that is very important is an appropriate configuration of intake openings – where they are, and what size they are can affect how the air moves and how well the fan or fans perform. If the door slams shut when you turn the fan on, it’s probably a good indication that your intakes are too small. Its perfect when there is just enough negative air pressure that the door gently closes. The slower the door closes, the slower the air is moving through the booth. The slower the air moves, the more direct rout it takes to the filter. Intense negative air pressure can also put a strain on the fan motor (or so I’ve been told).
The intake openings in booth #3 were in the ceiling. You can see them in the third picture (click on the illustration). The reason they have filters has nothing to do with dust collecting, it was actually to help keep sand from accidentally flying out – I guess during those times when I would be shooting straight up right? Hey – It could happen!
Everything so far told in the sandblast booth saga took place in and around Phoenix Az. where I had lived my entire life up to that point. The next element of the story however takes us to a far away land called Portland Oregon where I learned new things about moisture in booth #4.