Need help designing a paint booth

[rj440]

I'm looking to build a reasonably high end (for a home shop) paint booth but I don't have the means, space or inclination to buy a pro set up. Most everything I find on the net is a quick and dirty plastic and 2x4 kind of set up for the one time paint job, I want much better.

I have a half decent set up at the place I'm moving from, a fair bit of lighting but not great venting.

The place I'm moving to has a shop I've been building over the years with a dedicated room for a booth, 29' x 15' x 10' high. I'm going to put in angled lights up top and a bunch along the side. The problem with my current setup is to keep the lights sealed they're all enclosed with those horrible diffuser lenses that block half the light. I don't know if having open tubes poses an explosion hazard? I would love to have the max amount of light possible.

My bigger challenge is intake and exhaust, this is where I need the most help. The current setup just has a furnace fan blowing in through a filter and with the door open a bit, it vents out due to the positive pressure. It works but not nearly as well as I would like.

I was thinking of getting 2 or 3 explosion proof fans and venting out the gable with the intake coming from the other part of the building through proper booth filters. The other thought I had was to put the fans in the wall near the top between the angled lights, would be a lot easier to build.

The intake is another question, should it be near the bottom of the non exhaust side or could I build that into the top between the other bank of angled lights?

Thanks for any help or insight anyone can provide. There's a fair bit of expense involved so it would be unfortunate if the setup didn't work any better than sticking a fan in the door

 

[txvwnut]

The diffusers won't be a problem, I had eight in my booth and only used four at a time. All my lights were mounted in the center of the wall. I painted in a booth that had lights up high and it made terrible shadows. For my venting I used a 36 through the wall fan that was explosion proof, the booth was set back from the wall so I made sort of a venturi between the booth and the fan and it worked great. My booth was 10 high by 30 long and 12 wide all 2x4 and Sheetrock construction before the EPA outlawed that style of booth. I used regular paint booth intake and exhaust filters and just painted the inside with latex semi-gloss house paint.

 

[jloehlein]

I don't have much experience here, but my understanding is that you want the exhaust low, so that you don't end up pulling dust or overspray back upwards, where it may fall back onto whatever you're painting. I believe that is why pro booths have the vents in the floor, directly under the cars.

Also, as far as fans on the intake or the exhaust side, an intake fan could create a slight pressure, helping reduce dust infiltration, but it also seems more likely to blow crud around the room. If you have a well-sealed room, exhaust fans should be able pull dust away from the car without you worrying about dust coming in from outside.

I built a quick booth in a room in the middle of my garage to use a couple of times. I put a fan on the intake side, blowing into two ceiling diffusers because I was worried about dust infiltration. It was too high volume though and ended up stirring up a bunch of dust. I also knocked some holes in the walls down low for exhaust and ended up putting some box fans blowing out of them. I filtered the intake and exhaust with some 2" deep, pleated MERV-11 filters and added some paint booth filters to the exhaust, too. If I were to do it over, I would integrate the fans into the exhaust and have no intake fan, just a row of intake filters in the ceiling.

Here's a quick shot of the intake side that I threw together real quick (in the storage area above where I was painting). This is probably a better example of what not to do at this point, but it should give you something to think about. The filtering was pretty successful, at least.

And the exhaust side. There are matching exhaust "holes" across the room from each other.

 

[sberry]

Not sure if you ca n search threads . one here 3 months or so.

 

[Rex_A_Lott]

Ideally you want a down-draft booth. Filtered air supplied from the top, and exhausted from the bottom. Hard to do in a typical shop. You like the booth to be positive to the surrounding area, to keep out the dirt...so ever so slightly more supply air than exhaust.
Buy the best intake filters you can afford. These will probably be a pleated type filter. All these filters are rated in efficiencies, for a given particle size. Find a good filter rep and he can help you out. American Air Filters comes to mind, but there are many others. Camfil, Viledon, etc. Do a search.Make sure they are sealed good, around their frames, and filter the air, not letting it bypass the filters.
Your exhaust filters are to catch overspray, arent going to help your process, and are just to keep paint off your neighbors. Let your conscience be your guide.
The booth is not magic. The best thing you can do, is probably what you are doing already....get the dust off, blow it off, tack it off, do all your prep work OUTSIDE the booth. The least dirt you can bring in with the job, the better the result. Good Luck!

 

[cybrdyke]

Are you building to code? Gonna get inspected? Gonna have insurance?
If so, lights need to be paint booth rated.
Good luck

 

[sberry]

A paint booth is negative. Fumes are drawn out.

 

[sberry]

Ideally you want a down-draft booth. Filtered air supplied from the top, and exhausted from the bottom. Hard to do in a typical shop. You like the booth to be positive to the surrounding area, to keep out the dirt...so ever so slightly more supply air than exhaust.

You want less. A clean room would have positive pressure. A paint booth is neagative. It needs to be, under pressure fumes would be blown everywhere, out every crack, back out the intake.

 

[Rex_A_Lott]

You want less. A clean room would have positive pressure. A paint booth is neagative. It needs to be, under pressure fumes would be blown everywhere, out every crack, back out the intake.

Not really. You want to keep the dirt out. The fumes wont be blown back out the intake, it is slightly positive for the exhaust you have. The booth is treated like a clean room, if you care about quality.

 

[sberry]

Look up finishing academy for booth basics. If there is pressure in the booth how does air get in? A booth is negative pressure to create air movement in orderly fashion and be cleared out. A room under pressure blws air in all directions.

 

[sberry]

I need to learn phone stuff, dont know how to copy link. finishing academy paint booth basics. easy read, got it all

 

[jloehlein]

A room under pressure blws air in all directions.

This is the problem I had in my setup. I ended up painting with just the exhaust fans on and only turning on the intake fan to really help clear the room out after the paint had flashed.

 

[sberry]

There is normally no intake fan on in these setups, its not needed and only used in very tuned systems.

 

[sberry]

Like a lot of things it takes a bit to get mind around it and make it a reflex to "see how air moves" for lack of better words. The finish pages have some drawings and pictures.

 

[justanengineer]

Not sure what your lack of means really means regarding budget, but you might keep your eyes on local auctions for a professional booth. I've seen many booths sold at shop closing sales for peanuts, rarely over $1k and quite often closer to $500 for really clean functional setups.

 

[matt01073]

our shop currently has a blow therm booth but prior to that we ahd a makeshift booth in a room , a few things to keep in mind are depending on how much airflow your ex fan has and how tight your building is if you are heating your building you may have issues with the heat if pulling enough air flow to disturb the draft to the furnace . also will **** the doors shut in a small buildings . that said we had a very large explosion proof fan in a wall and filters in the booth doors 12 x 10 opening and it worked for years but it did effect the way our waste oil heater ran on the other end of the shop in a 4500 square foot building with 16 foot ceilings . our current both is a full downdraft pulling through the floor through a pit 5 feet deep 24 feet long 3 feet wide tied in to a 36 inch fan , airflow comes from the ceiling and the intake duct is about the same size as the exhaust and runs through a 1.2 million btu furnace outside the building before it comes in the building . the ex fan will not even start unless the intake blower is running if it did it would likely **** the doors in . the booth has to have possitive pressure . I know that you are not looking for an expensive commercial set up but just throwing a few things out there to think about . as said above spray booths at auctions are not big sellers and can be had fairly cheap but can be a pain to move ideally a down draft booth will be best where air is pulled through the floor and many booths have a base where you drive up a little onto grate work so the duct work is not in the building floor . 2nd choice would be a semi down draft pulling air from very low on the sides and intake air from the ceiling both will be much better than a fan in the window and no intake air flow . last try to end up with ex filters or depending on what you spray and how much ex flow you have you will overspray anything in your yard

 

[sberry]

A ready made booth takes a lot of room and is used occasionally. I have a big building but dont have built in. 99.95 pct of the time it used for something else.

 

[sberry]

http://finishingacademy.com/training/aero/aero_mod3/aero_mod3_intro.html If you google it again it may come up with a new version but this is it. I have a roll up. If you divide the room with a curtain you can run the heat.
I don't even bother filtering the air in, it comes over the top of the end, its down draft and clean. I show 2 pics that look the same but they are not, one is fan running, you may see how it has pulled the curtain corners together.

 

[sberry]

the booth has to have possitive pressure

I am sure this could use a re word. The booth is negative with no draw on the building it is in, as you said it will pull air down a chimney, mine does too, I open the walk door and its about right. Because of the volume of air being moved in your system they have added a fan, it is still tuned so more is being drawn that pushed. Adjustable balance system.
I had a bit of an issue so I actually down sized my fan and it really helped. It still clears but is a lot easier on heat. I can make near half a million.

 

[06 DIESEL]

The property that I bought had one in it at one time. There is a 3'x6' recess in the center of the bay and 12 filters in the ceiling that are 2'x2'. The recess in the floor has a 12" pipe going to the outside of the garage that at one point had a fan on it. The attic has extra vents on the side of the gable with duct work going to them from the vents in the ceiling. It appears that it would have worked very well, but having the recess in the floor has been a pain for me since I am not a painter, at least often enough to justify the recess in the floor.

 

[sberry]

Mine goes out the end but the set up is 40 ft long. It works well enough I really don't have to clean up much, the floor can be washed but I dont usually do it.
Sometimes I turn the fan on and use an air blower to tidy a little and more so or even some cardboard on the floor if I am painting a low car. There is a filter that gets tossed in front of the fan.
I had some issues, in effort to clean up an put a new belt on over powered it, someone had used it no filter, we fixed it all and in the process I downsized it a bit. The thing goes in the loading dock door, I can move the whole deal with a 2 wheel cart but it stays in place and close the door right over it.
I must have not finished the shroud as of this pic.

 

[sberry]

Now,, having posted all that I realize the shape and scope do not match all smaller garages but the principles are fundamentally the same.
I had some idea what I wanted and some was design an build ad some is face it as I went.
As we mention in other treads about features and how it works and I was trying to get as much in as I could and did. The reason it doesn't need to be super clean and dust free is it really works so well or well enough that making it any better would be a long chace for a little nibble.
I usually move equipment away from the end wall but the door is still white after a hundred major paint jobs, the ar is moving right where I want it, I am always trying to work in to the air stream from upwind, the over spray has been drawn in to the stream and there isn't any real cloud in the air unless I over shoot something.
I would like some smoke machine to look at the air along the floor but it doesn't kick up from walking and dragging a hose. Any thing loose in the air has been cleared before paint and this whole deal takes 10 minutes to be curtain ready, small stuff can be done in front of the fan without complete set up, a rim or a part. I use a pallet jack and can rotate the box while working allowing to stand up wind.
All this can be tailored in small spaces, have painted several cars with a couple box fans and done many make shift conversions in old buildings, sometimes with on site materials in short order.

 

[sberry]

Here is a way to get the feel for this. Take a small twin window fan put in a bedroom window. Make sure there is a window or door open to the rest of the house, get some incense go in room and play with the door opening. With door latches and room tight no air moves, there is a sweet spot with the door ajar and the fan will pull it open unlatched.
Too mush and the fan looses its pull as air velocity drops but a small rubber band on the door is about perfect. When its working right one can stand in hallway next to door and burn 10 sticks of sheet in it and not smell a thing.
Proven feature in dorm room parties.

 

[sberry]

A proper designed bathroom has a gap sized right under the door so when its closed fresh air is drawn under or thru a sized vent so the fan creates draw, with a door open a bathroom fan really doesn't do much.

 

[sberry]

I don't look in on the heating forum here, I should, I could learn a lot and an sure there are threads there about ventilation. Most of my painting is done, I don't have HVLP gun and would in some cases today, would save a lot of money with some kinds of paint.
Overspray is reduced and a guy could easily paint a car in a single stall garage without making too much of a mess.
One of the reasons you see so many pieces all covered and protected in makeshift set ups is simply they are not working right.

 

[sberry]

It took me building a few things wrong before I got it right, once I learn to get it right I try to keep on some more fundamental principle so I reflex or visualize a push/pull/draw and a swag.
My neighbor just died, he had tried with the daughter to go over the heat but she called me in a panic and wondered who to call,,, ha. Her dad had salvaged and reman the whole system and to her it looked like, well she don't know so when it was being done the man didn't need my help, I never seen the finished product but once you backtrack a minute and follow can see the raceway to the hallway and find the furnace intake under register in wall. The scheme really worked well and was thought out by a master. Couldn't get blocked by closed doors or renovation.

 

[sberry]

My booth leaks in spots, its minor and is drawn along a path that doesn't involve air stream over the work. Leak down and venting are not a bad thing, the vapors never pool. The amount of fan needed in a garage needs to be slightly more than the intake area including the leaks.
So,,, if one split a garage with a plastic sheet you could either intake directly from outside minus leaks and leave a open door in building also or intake from the building and bring all air in thru a walk door or window.
The different rigs are if one wants to use make up heat. We have used 2 running salamanders, a wood stove and electric heates on in one half, the warmed air is then pulled in to the booth.
I can visualize a small entry door jamb hinged to a wall with a couple furnace filters above. Swing this little section out and unroll a sheet and weight it to the floor.

 

[sberry]

Ok, mine has the top of the sheet taped to a header made of tubing cause I had it on the end wall and that is the intake but in a common garage with a ceiling a simple angle flashing screwed up with the sheet taped to it and a roll for a tube on the bottom.
I used a winch on my side wall as it was 40 ft but the end wall I simply pull and wind up a little rope.
In a ceiling garage it would be a lot easier to fit than in a steel building. There is another shining bubble or 2. I roll it up as soon as I am done and don't let it get caught in a windstorm and originally I bought a huge roll of stuff thinking I would need replacement but this has been in 20 yrs, I had to re duct tape the sheet to the roof purlin once, other than a little ding from a light and where someone shot it with a spray gun no reason to think it wont work another 20.
The header on the end wall could have been flat board. It seems the duct tape came loose and I zipped bead of old silicone across it.
I was going to be a smartie and hook battery drill to boat winch but I don't use it so much anymore and that's the nice thing about being a semi/make shift setup, wall all gone and stored overhead 100%. I want it when I want it, used it a lot at one point but glad its not built in. I use it for warm car parking in the severe winter, have a floor drain, use it 10x more for other things than painting.
The roll could be pulled in to a sheet metal enclosure if it bothered a guy.

 

[sberry]

Some of the stuff I do would actually be easier in a small garage and a lot cheaper too. Taping a 20x40 sheet in to a ceiling aint for everyone but in a 10 ft with a ceiling wouldn't be too hard to do from a ready sized 10x20 sheet, standard flashing, could improve it with concealment covers, even hide some rope.

 

[Rex_A_Lott]

To sberry- I read the info in your link, it has some good info in it. But they are talking about a booth where the desired airflow is end-to-end, not top-to-bottom like I was thinking of. So we are not comparing apples to apples. Even they said there are more ways to choke a dog than feeding him butter. Your setup appears to be working for you, so Good for you. You mentioned wanting a smoke machine to check air flow. You dont have to do that, they make smoke tubes you can buy to check air flow. They are a glass tube that you put a squeeze bulb on the end and they produce smoke through a chemical reaction.
Simple but effective.
To diesel06- just wondered of you could put heavy-duty grates over the area in the floor that is giving you problems? Maybe cheaper than a concrete job.
Good Luck

 

[sberry]

Top to bottom end to end the air pressure has to change to negative to get flow. For most home garages painting looses a little luster after a bit, one paints lie a bat out of hell for a bit, then he catches up, then it becomes more work.
I read thru the link and even a code book a time or 2, I might have read it more than once and every time I get a bit more.
The version I show here isn't the only way I done it, its the easiest cheapest best fastest way I have ever done it.

 

[sberry]

Downdraft describes the air flow pattern. The thingy in the floor works good because it simply pulls down and around and dirt isn't kicked up. Mine is nearly the same. A guy can walk around in it and feel the warm air come in when the fan is turned on. I was mentioning smoke in passing more as a concept than that I really give a darn. How much does the smoke thingys cost?
A guy can see air move with cigarettes. Here overspray gets caught in the air stream before it hits the walls. The room is about 15ft wide usable. I went out and sorted thru irrigation pipe and found a 40 ft 5 inch diam. The booth is really 39 ft long. I have come in a day later and paint accys behind curing paint if I work near the fan.
I was going to paint a tractor this winter but am going to see if I can run it a season again and get it all housebroke first. I got a pump that will likely get a shot. Would make it seem like a different machine.

 

[rj440]

Thanks for all the ideas and information guys! A few of my own thoughts:

- I can't really do a downdraft booth as there is a concrete floor already, the grate idea above it is interesting but most of the cars I'm painting are full restorations so they don't always run at the paint stage. I would need a winch in there to pull the car up, my Eldorado weighs 5300 lbs, hard to push it on polished concrete let alone over anything.

- So exhaust out low seems to be the ticket, side draft booth but only on one side. Unfortunately it will eat up a bit of space but what can you do. I can either put the fans in low with ducting and filters around them or maybe mount the fans high and run ducts down to a flilter bank below?

- The intake filters will be high up the other side of the wall by the sounds of it. That side backs onto the rest of the shop so at least it's drawing warmer air than if it came from the ceiling and cold attic.

- All my body work is in another room, this is a dedicated clean room for painting and all filters will be proper ones like paint shops use.

- I've thought about finding a used booth but they don't come up often where I am and would require a ton of work to retrofit to my set up so I gave up on that.

- I'm going to read through that Finishing Academy site! I would have done a search here for booths but I've never had luck with searches, get about 200,000 hits anytime booth or paint get mentioned in any vague way

 

[bullnerd]

Good example in this guys thread, skim in a few pages. Id say it works. have you seen his work! At least you can ask him how he likes it and if he would change anything.

http://www.garagejournal.com/forum/showthread.php?t=123882

 

[sberry]

I can stage and wheel in or out from the side. I did this a lot bc,,, before camera, I painted a multi color not to long ago, did one color, moved it out and did the next one.
In this booth there is enough room that a guy can progress without overspray on finished work.

 

[rj440]

Good example in this guys thread, skim in a few pages. Id say it works. have you seen his work! At least you can ask him how he likes it and if he would change anything.

http://www.garagejournal.com/forum/showthread.php?t=123882

Thanks, that looks good, very similar to what I want to do except I'm going to add the angled lights in the ceiling as well as the wall lights. Very similar building to mine as well, mine's 30 x 50 in a Texaco service station theme. Once I finish the whole nine yards I'll put up a thread. It was inspired by a thread here, I don't have the guys name in my head but it's his fault so I will look it up when I post it

Here's a glimpse of the lights I built in the current shop, the overhead lights were there before but I won't be adding those in the new setup.

 

[rj440]

I can stage and wheel in or out from the side. I did this a lot bc,,, before camera, I painted a multi color not to long ago, did one color, moved it out and did the next one.
In this booth there is enough room that a guy can progress without overspray on finished work.

Your building looks huge so I would imagine you could pretty much paint anywhere in it and not have dust and overspray issues like you would in a small shop

 

[sberry]

Paint goes everywhere. Some of the industrial coatings are slow, some car paint so fast its dry before it hits the ground. I tried to make the point these things would work in most places and has.

 

[rj440]

The first car I painted 20 or so years ago was in a dirty garage full of all sorts of things, no fans, just a man door open and it came out virtually dust free (but there was overspray on everything) Since then I've sprayed in a far cleaner room and ended up with way more dust in the paint. I figure if you run any fan, the room had better be squeaky clean.