Howdy,

I'm going to be building my own paint booth inlieu of buying one. I have most of the materials so cost (other than time) is minimal.

I've seen/read some posts regarding building, but nothing in the way of "airflow." So, my question is: "Do you build so the air flows up, down, or to the rear?

I have a 30 inch Broan rangehood for the start of this project:

I plan to build a cabinet around it; I'm just not sure if I want the hood on top (air flow up) or in the back (air flow to the rear). I don't want to attempt to put the hood on the bottom because of it's shape (air flow down) and the fact it'll raise the "base" up a minimum of 10 inches to around 15 inches because of the venting.

Assuming my pics posted, this next one shows the underside of the hood. I intend to modify it so that it will accept furnace filters as the "grease" filters that came with the hood won't collect the paint mist whereas furnace filters will.



Oh, the fan in there is 45 cfm....that should be enough.

I'll use a metal dryer duct to vent the fumes out of the house. That will be attached to the top (with modifications). The hood originally had a stainless flue (gone now) but I figure an adapter will be easy enough to make or buy.

I have plywood, plexiglas, and steel to build the box. I'll probably go with plywood as it is a lot easier to work with. Plexiglas probably can't be cleaned too well after some time and steel requires me to do some welding, not to mention the increase in weight.

I'll also wind up adding a light or lights to the inside of the cabinet. The lights with the hood won't properly illuminate a model, so that's a must. The switches on the right are fan "on/off," fan speed (3), and lights "on/off." I'll probably build so the switches are accessable from the outside.

So, airflow to the top or to the rear? Your comments will be greatly appreciated.

Thank you!

Mike

p.s. The hammer (on the right) is not for the hood, it's for the IT-28 on the left (if necessary)

Crikey, what a starting point. I have built one using a bathroom extractor and I extract the air upwards. However, my airflow is far from satisfactory, with much bouncing out the booth and into the room. Time for a rethink, it could be my filter is causing too much resistance.

Shaun,

From what I've read, furnace type filters are the best...they allow good airflow which aids in venting the uckky fumes and will trap a lot of the particles which of course keeps the motor reasonably clean.

What type of filter are you using? And what's the CFM of the fan? Someone had posted here at Armorama that a bathroom fan had quite an output, but when I hooked my rangehood up to some power, set it on high, I was afraid that as I'm shooting my model all the paint would get sucked away from it. It's pretty powerful.

Hopefully someone out there will have answers to our dilemas as I am leaning towards venting out of the rear...setting it up as the second picture shows.

Mike

Hi, I've no idea what the CFM is, but there seems to be a reasonable flow. The filter box I have built has cooker hood filters over the inside face and there are 3 small holes on each side. There is paint build up over the holes showing that there is indeed some extraction in progress and you can feel a slight breeze if you put your hand by the holes. I think I need to make more / bigger holes to allow more air to escape, therefore making the extraction process more efficient. Part of the problem seems to be the paint "rebounding" off the sides of the spray booth. I've no idea how to stop this.

I work with ventilation and have talked this question over with one of the suppliers we use.

The best situation you can have is if you can have about 6 ft to 9 ft from the fan to the actual area capturing the spray. In that was the combustibles get mixed with air before they go through the fan and the heavier spray particles get caught on the extraction surfaces to dry. In this way you do not need a filter at all.

Range hoods are made for combustible solids, that is why the filters are so close to the source. Paint on the contrary to cooking grease and build-up is not flammable after drying and curing.

Which also means it doesn't matter which direction you extract the surplus air from the spray area. If you have the room behind the area for your spraybooth, the best direction is in the direction of the spray, which would also help the fan extract the fumes. Downward extraction seems impractible, but is feasable. Upward extraction falls inbetween the other two. Personally I built mine upward, because I didn't have the space behind the spraybooth.

Hope this helps...

Shaun,
Can you take the cooker filters out and try a furnace type filter? More often than not, cooker (grease) filters are porous...grease being thicker/larger than paint from an airbrush and a lot of the mist is getting to the motor/fan. I'd be willing to bet you'll get good or better flow with a furnace type.

Brian,
I have room either above or behind right now. The pictures I posted show where the booth will go. I may wind up having to move it eventually, so, I need to consider space in the rear...more than likely I'll build it so that it vents upward (all the better to show off the stainless . If I move the booth either left or right of where it's sitting now, I lose the room behind (it's in the corner).
I won't be able to have the fan too high, but I see where if I vent behind, the most common direction of painting, it would be better. Still the dilema....

I appreciate the input....

Mike

I built a downdraft booth..... It takes a more powerful fan.... But they seem to be the best type IMHO

Sorry, I relooked the fan....it's 450 CFM....

Matt,

Anyway to get a pic or two of your downdraft?

Mike

um..... sure....

My fan(s) are actually on the Back pulling the air throug the pipe.....(they're the 2 black things inline with the 2 vertical stacks behind the booth.... I got the fans as surplus.... 1 didn't seem to be enough so i bought a second one.... There's 2 furnace filters w/ some quilt batting in between. and a lazy susan on top. I'll try to take a few more pictures when i can get some time...



oh... try to keep the ducting as short as possible too...

Matt, thank you. I was trying to figure out how I would, IF I could, do a downdraft using the hood I have. And I wanted to see which way you had it venting. It may be easier than I thought.

It looks like your filters sit inside (easily replaceable) and would assume that below them you have "cross members" supporting them, the lazy susan, and your model. If I do an updraft, then I have to create slots in the cabinet or attach slots to the hood. If I do a backdraft, then the onus is keeping them upright. Your booth seems to be very easy to clean and maintain.

A thought I had (or may have read way back when) is the direction of spray: if you vent up, you're drawing some of the paint away whereas down or back, you're not losing any....

The cabinet appears to be either glass or plexi...hmmm.

Again, I appreciate your input.

Mike

Yep... i was given some 3/8" thick Plexi........ And the rest (fans & Sheetmetal ducting) cost about 60 bucks or so. There;s a pair of Alum. anglr supporting the Lazy susan.... and a lip supporting the filters.

good day mike

here's a link that i think would help ya
Link

it has all the jargon and the techie stuff...

although it's basic design, if u like more techie stuff pls read the AS/NZS 4114.1:1995, Spray painting booths Part 1: Design, construction and testing This Standard is intended for the guidance of manufacturers, designers, users, statutory authorities and others associated with the construction o f spray painting booths. or similar

or some other spray booth design standards

Silantra,

That link is super... probably all the information I'll ever need to get this thing built. Looks like downdraft is the way to go...the site clearly explains the issue with what happens while painting in the different environments.

I should be able to modify my hood, or just use the motor, to do a downdraft.

No work or school today, so.....I may have to get busy



Thanks all!!

I have a homebuilt booth,I arranged it to draw air to the rear.I also had my fan as the last part,the booth,the duct,the fan.
My reasoning is,the fan draws better than pushes air.My booth is slightly larger than what I build,so there is a strong breeze from behind me,through the work area

For those that have replied with information, "Thank you!"
For those that have looked, PLEASE do check out Silantra's link. It has great information, techie in nature, but still answers the question.
I've decided, and started, to build a downdraft. I'll post some pics here as it comes along. Hopefully this will help others that are trying to decide which way to go.

MTF,

Mike

Okay, got busy today.

This pic shows the backside of the base made of 1/2 inch cabinet ply (with hood) and the venting.



This one is the bottom view with clearer detail of the venting attached to the hood and the "framework." The cord was attached to the wires from the hood and run through the first piece of vent.



This one shows the base and hood from the front. I inset the piece of ply to allow a wee bit'o storage below the booth. I plan to attach the actual "painting area" so that it's a bit smaller that the base. I want to be able to access the fan and light switch (on the left) from outside the painting area.



Now's a good time for comments and suggestions from you all.

This is based on the article dropped by Silantra.

Mike

Mike....

nice progress and changes u have made here....
although i have read the articles well, but my spray booth was rather more or near like yours.... u job is fantastic.....

Hey all, got really busy these last couple of days.

This photo shows the almost completed booth. I used 1/4 inch plexi for the side, top, and back panels. They are held in place by 3/4 x 3/4 inch framing that was dadoed for the panels to fit.



This one shows the 1/4 inch pegboard that will hold the model up as I'm shooting it. I think that the air draw through the pegboard will work well.



Another shot:



I was able to keep the light, fan speed, and power switches within easy reach.



The lazy-susan was also made out of pegboard.


p.s. Polaris Sportsman 500. Yellow baby!! Gotta get some air!!!!



I still have a fair amount of clean up to do. The furnace filters will be attached to the underside of the pegboard "base" and I intend to add a low-profile flouro light to the booth; the lights on the hood are okay, but not enough.

Coming along nicely I'm thinking. I can't wait to actually get it downstairs and use it!!

Debating about adding "doors" to the front (plexi too). I like that idea as it'll help keep dust out while the paint is curing

Mike

:-)
Don't it tho!!!!

Shoot, I went back outside and took another look and "Sho'nuff" it could pass for a toaster!! Big one tho!

Mike

Hi Mike...outstanding job man!!!
perfect!!