Spray Booth Filter, Blower, and Door Choices

Finishers discuss desirable characteristics in a new spray booth. December 1, 2005

I'm a high-end custom furniture finisher in South Florida and I am looking to set up a small finish shop to take on some overflow work from other local shops and such. Most of the work is dyes and glazes, with the occasional polyester job. Currently, we have two side downdraft automotive booths with doors. I'd like to hear about other people's experiences with booths. I'm not looking to spend a fortune, but is there any technology that is cutting edge, or worth the extra investment?

Forum Responses
(Finishing Forum)
From contributor R:
First off, unless you own the building, you need a landlord who will allow you to install one on his property. Building permits, local fire marshal laws, and zoning concerns can certainly cost as much as, if not more than, a spray booth. I'd grab the yellow pages and look under "spray booths" and spray equipment and I'd do a Jeeves or Google search.

I suppose you could call me a high end finisher, and I'll be darned if I haven't done some high end finishes under cruddy situations. Right now I'm in a shop that has a Binks wall booth and 15 feet of accordion type filters attached to it. The room is about 20X15 and the front wall is the exhaust booth. The two large doors used to enter the booth have eight filters per door. Once I spray something, I just roll the item in front of either of those doors, and the warm, clean air coming in from the outside helps to dry what was just coated.

P.S. As per code in California, I enter and exit the booth from a separate door, not one of the two filtered doors.

From contributor D:
We have two automotive type booths. One is a downdraft and one is a side draft. Both work fine, but I like the side draft best. It seems to pull better for the way we are set up to spray. We are a cabinet shop in Florida.

From contributor S:

Try to hook up with a good spray equipment distributor in your area. They will help you size and configure the booth for your needs, available space and budget. A good rep will be worth the commission and keep you from making a serious mistake. They should also be well versed in all the applicable building and fire codes involved and when necessary, they will be your intermediary to work through any code issues with local inspectors.

I have a large open face booth with air makeup. The booth exhaust has a Variable Frequency Drive (VFD), which was an upgrade I am very glad I went with. The VFD gives you this: as the exhaust filters load, the fan senses the increase in static pressure and then automatically increases the fan speed to compensate. This way, you maintain a constant air flow in your spray zone. Without VFD, you size the exhaust fan to pull a significantly greater airflow than you need when the filters are new, so that when they load, you maintain an acceptable air flow. The bottom line is your airflow is going to be within a range, versus with VFD, it will always be exactly what you want it to be. VFD was not a costly upgrade.

From the original questioner:
My thanks for your responses. Do you feel there is a big difference between open face and a booth with doors or filtered doors?

From contributor M:
Open face vs. filtered doors? Two words: kamikaze bugs. I wish I had an automotive booth. My rep tells me he does not see a significant improvement over semi-, side, cross, and whatever else there is until you get to down draft and build a pit. I am going to have to check into the VFD. Contributor S, how much extra did you have to pay for it?

From contributor S:
Contributor M essentially makes the point on open face or enclosed booth. An enclosed booth is needed where you cannot control the dust environment outside the booth. I have an open face booth, but it sits at one end of a large room that is dedicated for finishing only. I also have a filtered air makeup supply dedicated to this room.

I'd have to dig through some old paperwork to find costs on the variable frequency drive option for the exhaust. I'm going to guess that option was in the range of $1500. It might be more expensive on a retrofit.

VFD is one part of the package. You also need the extra cfm capability on your fan for a VFD to work with. For example, my 14'x10'h booth is adequately served by 14,000 cfm exhaust fan, however I have a fan rated for 16,000 cfm, so that when the filters load, I will have the extra fan horsepower to maintain my airflow when the VFD asks for more exhaust.

I'm just regurgitating some of what I learned from my equipment rep. He has spec'd thousands of systems. The professional help is out there and I strongly advocate finding it.

From contributor H:
I am a professional finisher in California. Last year the company that I work for installed a spray booth from a company called Spray Tech that is an auto spray booth. I think that you are looking for a smaller version and this company had a lot of different options. The booths are pretty reasonably priced and they (the company) were good to work with. This isn't necessarily a promo for them but I just wanted you to be aware of my experience.