spray booth?

[Eric John]

morning!

So as i'm gearing up for spraying these cabinet doors,( forgive my newbie questions)

i'm planning to make a small collapsible spray booth in garage.
probably 8' x 8'. some kind of frame with plastic sheeting.
fan with filters to exhaust spray.

i have always used wipe on finishes and brushed finishes before so i really
dont know a lot about spraying.

do you guys spray in the booth then move the wet pieces out to a dry rack?
or leave them in the booth till dry?
is hanging the doors a preferred method? or lay them flat then shoot the backs wait and
shoot the front?

need a little help here, appreciate all comments.

Eric

[Kevin Jenness]

What are you spraying? A properly set up spray booth will protect you from particulates, fumes and explosions. Are you exhausting outdoors? Do you have a makeup air source? Do you need an explosion proof blower? Can you pull enough air flow to be effective? A rule of thumb I have seen calls for 100 ft/min air velocity across the booth section.

I have a rack away from my spraying area. I shoot the backs, let dry, then spray the fronts.

I used to sub work out to a guy who would lay an array of panels on horses and planks, then work in sequence starting farthest from the fan intake. It was efficient and he got a good result, but he had a serious high powered blower.

[Jim Becker]

Making the broad assumption you are going to be using waterborne finishes...not solvent based products which require special gear and safety planning...a booth to help contain overspray particulates is a nice thing to have. Personally, I prefer spraying things flat, not hanging. If you are only doing a small job, leaving things in the booth to dry can work, but for larger jobs, it's kinda necessary to move the components to dry elsewhere while you move on to spraying additional components. So the nature of your work is going to dictate how you handle that.

[Eric John]

What are you spraying? A properly set up spray booth will protect you from particulates, fumes and explosions. Are you exhausting outdoors? Do you have a makeup air source? Do you need an explosion proof blower? Can you pull enough air flow to be effective? A rule of thumb I have seen calls for 100 ft/min air velocity across the booth section.

I have a rack away from my spraying area. I shoot the backs, let dry, then spray the fronts.

I used to sub work out to a guy who would lay an array of panels on horses and planks, then work in sequence starting farthest from the fan intake. It was efficient and he got a good result, but he had a serious high powered blower.

be spraying sw emerald urethane this time around.
bought the 1.8 fuji tip,( thatas what i heard works best)
thte boooth will be setup inside my garage (2 car)
i was thinking two box fans with filters on one side and an
opening on the other with two filters side by side.
then have to come up with a drying rack
Thank you

[Scott T Smith]

We use pop-up canopies all the time in the shop to make a temporary spray booth. They work well.

[mark mcfarlane]

i'm planning to make a small collapsible spray booth in garage.
probably 8' x 8'. some kind of frame with plastic sheeting.

8'*8' seems kind of small to me. If you have room I'd go a little larger, at least 10'*10'. You want to be able to walk around whatever it is you are spraying. Perhaps you can set up a dummy spray area, place some objects in it and walk around them and see if you are bumping into the virtual walls. I'd want at least 3 or 4 feet on all sides of what I was spraying. If you are just spraying cabinet doors you can put them against one wall and 8' is enough but if you are building a reusable knock-down booth that may be used for spraying larger cabinets, tables, etc then 8' may seem cramped.

[John TenEyck]

be spraying sw emerald urethane this time around.
bought the 1.8 fuji tip,( thatas what i heard works best)
thte boooth will be setup inside my garage (2 car)
i was thinking two box fans with filters on one side and an
opening on the other with two filters side by side.
then have to come up with a drying rack
Thank you

Even with a 1.8 mm N/N set you likely will need to thin Emerald Urethane at least 5% to get it to atomize well. You also may need to add some Extender if the RH is low since you are using a turbine. Only way to know is to shoot a test panel and see how it sprays, flows out, and dries.

My opinion on spray booths is they are useless unless you have exhaust and make-up air, which you are planning for so that's good. I agree that an 8 x 8' booth is really small; however, it may be adequate if you put your workpiece on a turntable such that you only need to stand at the front. On the exhaust side I would not put filters in front of the fans as they will just clog up over time and defeat the purpose. Box fans are cheap and if you set them far enough away, another reason to have a larger booth, the overspray will drop onto the floor before getting to the fans. But even if some finish does get onto the fan blades they will still move a lot of air and when they eventually get really slagged up you can replace them for less than $20 each. On the make-up side I would do nothing, just clean up prior to spraying so that dust doesn't get sucked into the booth while spraying. I've used a temporary spray booth for over 10 years, exhaust fan only, open window for make-up air, and never had issues with dust getting onto my workpiece. Note: I only spray WB and shellac because my fan and lighting are not explosion proof.

John

[Stephen Roth]

I use a pop-up booth, with the front made from plywood. The back is canvas drop cloths, which allows me to extend the booth the one time a year I need more than 8 x 8.

One thing I figured out (which no one mentions), is the placement of the fan. Most professional booths have a fan-wall in front of the person spaying. Some really high-end factories have the fans in the floor, which is not practical for most of us. So it seems that most people stick a fan in the wall in front of them mid-height (which tends to be above the work being sprayed).

I tried that for a while and found that the mist did not evaporate. It just hung in the air. After a number of messed-up surfaces with dry overspray, I realized that the fan was pulling the mist up, and gravity was pulling it down, which created a sort of zero-gravity equilibruim of the mist hanging out mid-booth. Of course, this is the worst situation.

So I put the fan all the way down at the floor in front of the spray area, and made the intake openings in the booth on the opposite side high up on the wall. Well, this works perfectly for the same exact gun set up and finish.



FYI, I shoot mostly GF Enduro-Var and GF High Performance. Levels great, but I hear bad things about Enduro-Var II.

For a fan, I use a 12" blower from Northern Tool, and exhaust the air out a window with the giant collapsible tubes they sell. I cover the intake with a Merv 2 or so filter just to protect the fan. I change the filter each time I spray a project. They are cheap if you buy them in a roll.

Stephen

[Bob McBreen]

Not a direct answer about a spray booth but before I spray in my shop I wet mop the floor. I find that this really helps keep the dust down.

Good luck with your project - Bob

[Ken Krawford]

If you're exhausting the overspray outside of your garage I'm not sure why you need filter(s). You'll move more air volume with them.

[Kevin Jenness]

If you're exhausting the overspray outside of your garage I'm not sure why you need filter(s). You'll move more air volume with them.

Filters protect the fan blades from overspray buidup and the external environment from contamination. We have enough microplastics blowing around without adding more intentionally. Same goes for "disposable" fans.

+1 on turntables.

[Tom Bender]

Stephen makes a good point about pulling exhaust from floor level. If your window fan is higher you could fix that with a false wall in front of it that stops 6" above the floor, giving you better distribution across the width of the booth.

[Alan Lightstone]

+ 2 on the filters and turntables.

[Michael Fink]

I'm going to drop what might be an unpopular opinion. I wouldn't bother with a spray booth unless you're SUPER picky or you have a shop that's beyond dusty into "ridiculous".

I have a big wood working shop where I spray. Make a LOT of saw dust in there; I do have a DC and recirculating air filtration, but still, there's a lot of dust. The equipment after a week will have a thin coat on everything. I spray in there all the time and have, without fail (well, if I do it right), gotten fantastic results. Yes, if you comb the finish with a strong light, you can probably find a nib or two on a cabinet face. But it's far beyond "acceptable" into close enough to perfect that everyone thinks its a factory finish.

Spray booths are primarily, IMHO, for when you are doing cars and a single nib can make the difference between good and great. But a car's surface is SO much smoother and easier to see imperfections compared to wood.

I spray all my primer and color coats without doing much of anything except blowing everything off. First 1-2 coats of clear the same way. When I get ready to shoot the last coat, I do typically wet the floor around where I'm spraying to keep any kicked up dust down. Hammer the coat to full thickness, turn off the lights and walk out ASAP (again, keep the kicked up dust to a minimum). 30 mins later, it's firm enough that dust won't penetrate into the coat, you can just brush it off when it's totally dry.

I'm sure a spray booth would be better. But to say "nobody would notice" is probably an understatement. If it makes you happy, by all means, but I'm confident that you can get a "wow" finish without a spray booth, I've done it many times. What matters a whole lot more is getting a consistent smooth coat down on a surface that's sanded to within an inch of it's life.

[Jim Becker]

Michael, something to consider is that the booth is just as much to keep the shop clean as it is to keep the workpiece clean. The waterborne finishes that so many of us spray put a lot of suspended particulate in the air which is why PPE is still mandatory when using them, even though there isn't the chemical risk like there is with spraying solvent based finishes. In my previous shop, I handled things exactly like you do and it was VERY clear a day or three after spraying a project that I had been spraying a project because every surface in the shop had a visible coat of very fine "dust" from the spraying process. Every machine, Every worksurface. Every shelf. Every everything. And that's with an air cleaner running to get at least some of it. That's why I plan on being a little more proactive in the new shop build and have a space that will provide some better control of the particulate and make it easier to keep things clean. A fan-filter system that encourages the overspray particulate to move toward and into it will help with that and even if "walls" are temporary, they will further help with that. All I'm saying is that there are actually two sides to this coin.