DIY paint booth (pic's)
Hello everybody, I'm a noob to this site. I thought I would share with ya'll my home built paint booth I built out in my shop. I just got it completed several weeks ago and was looking for some feedback on my air supply/evacuation set-up. Pic's first:
It is 14'x26' with a tad over 8' in height. It's a poor man's down draft. You can see the inlet filter in the ceiling and the returns are along the base boards.
The ceiling filter measures 3'x16', it blows a nice soft gentle air plume down over the car.
This is the air supply. I used 3/4" copper from my compressor (approx 70' of it), then transitioned over to PVC for the dryer and regulator. I stabbed in a window A/C unit for cooling while I'm in there sanding, buffing, etc.
This is the top of the paint booth. The duct on the right is my return air (there is another one on the left side of the booth just like it that you can't see). The big duct on the left is my air supply that dumps down thru the filter in the ceiling. The returns go all the way to the back wall then turn in towards the center of the booth and dumps back into the supply duct. This is where I need some advice, as you can see my air system recirculates the air, it doesn't vent out the paint mist/fumes. I was told that doing it this way might cause problems with "Die Back". I never heard that term before but I was told that the solvents in the air coming back into the paint booth would hit the fresh paint and could dull it. I guess kinda like blushing?
You're probably asking yourself, why the heck did he run the air system like that? Well, to be honest, this set up is in my back yard and I am concerned about the neighbors. I don't want to attract a lot of attention, but in retrospect, I'm not in there priming/painting every day so that was probably faulty logic on my part.
OK, back to my question, If this was your booth, would you reroute the return air to vent the booth to the outside and pull in fresh air, or leave it as is?
Looks great...a couple of things that i see and other pros here will chime in; with excellent information.
Personally i would MOST DEFFINATELY vent to the outside; you dont want to have solvent rich air recirculating 1. die back/solvent pop issues i can see happening 2. you just made yourself a rather large percussion bomb (I dont mean to scare you )...Haveing solvent rich air recirculating around will eventually raise to and past the UEL (Upper Explosive limit), i dont know what fans you have but thats a not a good combination. When that air mixture "leans" out and comes back through the range of flammibility and eventually lower than the LEL (Lower Explosive Limit), you have your greatest risk. PLEASE went to the outside, you'll be glad you did.
2. I would put a coating on the doors just to seal the wood etc not a big deal
3. Is your ducting sealed?...did you paint it with anything to help keep airflow up and dust etc coming off the wood?
4. Lights...Can you cover them with something to keep the balast and other associated parts out of the paint enviornment...I.E. recess them into the wall and cover with a piece of plexi.
I relise i didnt cover everything you asked just some observations/opinions on my part.
just an opinion from a hobbyist still learning alot to get serious about it..but..i wouldnt use the paint booth for sanding or buffing or anything else BUT painting..going to be real hard to wash down & get rid all the dust it creates when you need to paint with all those exposed lights and such..the term die back does make sense to me,i would think it would need fresh air and bringing back alot of the solvents into the paint area seems like a bad idea to me..it makes ense that it could mess with the paint since its probably about impossible to filter out the solvents in the air.i am in about the same boat as you are..ive been researching the best way to either build a paint booth or if it will about the same kind of money to just go ahead & buy one in the end..im in southern Ga..my main concern will be how to get rid of all the high humidity in it..very nice job on the booth though..looks like a pro job to me..good luck..John
Your construction looks good but there are a couple of concerns.
In most booths you only return air AFTER the spraying is done in order to maintain or increase the temperature of the air. I don't know about causing a die back problem but the constantly increasing solvent content of the recirculating air could cause a volatile condition and increase the chance of explosion. While you are spraying, and for a short time after, I would vent the room without recirculating the air.
I'd recommend against using plastic pipe for compressed air anywhere it can be bumped or anywhere low in the booth. If you use plastic it should be high, up around the ceiling, then run your drops in copper or steel. The PVC can explode if hit by a tool or walked into while it's holding pressure. Exploding PVC can cause sharp pieces of plastic to fly from the break. PVC can also tire with age and explode after it's used for a couple of years.
What did you use for blowers in the booth? How large are they and what HP did you use? My booth is similar, although no where near as nice and I've been using 2 squirrel cage blowers, one 1/2 HP and one 1/3 HP and it's only been adequate. Forcing the air through the filters really restricts the volume of air I can get and I really need more flow.
Thanks guys, OK, I'll change the air system so it will dump to the outside, I was leaning towards that direction anyway, I guess I just needed a little push.
Now my next question, I'm only using one blower (squirrel cage) it's a 220V one HP (I think) motor. I don't know what it came out of, but it moves a lot of air. The way it's set up now is it sucks the air out of the booth and dumps it right back in. When I dump to the outside, it will no longer be sucking air out of the booth, just pushing it in. Will I need another blower to help evacuate the booth, or would I be OK with just pushing the air in?
Len, you're not the only one to point out the PVC pipe. I guess that's what I get for trying to take the easy way out......dang it!! I'll git-r-dun.
Paul, Yeah, I'm going to paint the doors and I'll also get around the window A/C too. I'm not too organized right now. I've been pounding away on this booth for so long I wanted to get back on my Camaro. I didn't paint the inside of the ducts. It never occurred to me to do that. It's a little late now, so it'll have to ride as is. I was thinking about framing out the lights in wood then seal them up in plexiglass, but wasn't really sure if that's really necessary with flouresent (sp) fixtures. Anybody else have a take on that? I'm pretty much old school and used booths in the past with uncovered lights, but that doesn't mean I wasn't a nan-o-second away from becoming a Darwin Award Recipient, LOL.
Jon E, I hope I answered your question, sorry I don't know what it came out of, but if I had to guess, I would think it's from a 3 ton unit. It does move a lot of air.
Suthncustoms, are you near Valdosta? I'll be heading that way when the 10.5 Outlaws come to South Georgia Motorsports Park.
Keep it coming guys, this is good stuff.
If the fan is small you my need another to pull the air out. I have a large squirrrel cage unit pushing air in and that's all I need. However if the room doesn't clear fast enough for you then you'll need to change something. The problem with fans in the exiting air is that you need to protect and clean them.
1 fan blowing in and another out seems dumb to me. In Pump theory we teach that 2 fans in series bumps up the pressure, however flow is constant. If you have insufficient flow I'd advise adding another fan in parallel with the first. Whether you're pushing 'to' or pulling 'from' the booth is a matter of preference ('to' would be most peoples), if you have both or even 3 fans doing the same thing, that will give you the most FLOW...
Just my $.02...
SUPER nice booth btw...
im about 2 hrs from there.i am about 14 miles outside of a town called Millen..along the ogeechee river in the boonies..Millen is in between statesboro & augusta on highway 25..when is the race?
I found this article http://dodconf.swri.org/2003Papers/Thelen.pdf at www.garagejournal.com and thought it was pretty interesting. It outlines paintbooth ventilation theory.. positive vs. negative pressure, airflow, etc. Interesting read.
great article dave..thanks for sharing
I love reading up on the technical aspects of things. Thanks too for posting that link.
Thanks guys, this is great stuff. I'm going to try using my existing fan and dump the fumes to the outside and see how she does. That was a very interesting read Dave, thanks for sharing. Hopefully I'll hit the right balance and won't create a dust/mist cloud while painting. I guess if worse case senario arises, I can install a smaller fan on the exhaust side to evacuate the fumes, we'll see what shakes out.
SuthnCustoms, their next big race there will be 8-10 Sept. You can look on their web site, www.outlawracing.com to see if a race maybe a little closer to home. They will be at Macon National the end of this month if that's a little closer for ya.
Are there pictures in the first post?
why don't I see any photos?:confused:
rob;;;wanting to build my first paint booth..man. your paint booth is my dream..what is the walls made of and what did you paint them with?
Originally Posted by procharged 79