Downdraft Paint Booth

Photo: Downdraft Paint Booth

I finally got around to making the DOWNDRAFT Paint Booth that I have been dreaming of for years. I have been using it now for a couple of weeks and I am very happy! No paint fumes end up in my studio. They all go outside.

I do most of my painting with an airbrush or spay cans. I spray mostly clear acrylic lacquer or clear polyurethane out of rattle cans. I have a spray gun that I almost never use.

Why Down Draft?

My new down draft booth paint booth sucks the paint down onto my work.

Most paint booths suck the paint fumes out thru the back. I don't like that design because it screws up the spray pattern of my paint when it comes out of my spray can. It also sucks the paint past my work and thus tends to waste a lot of my paint. The paint gets sucked out. It does not end up on my work.

Get an EXPLOSION PROOF Fan

I have been debating with myself. Should I put this on the blog or not due to paint fume explosion risk.

My new down draft paint booth is powered by my big 2hp dust collector. My dust collector is OUTSIDE over 20 feet away from my paint booth. Paint fumes are diluted or turn to dust before they get to my dust collector. The motor on my dust collector is a TEFC (totally enclosed fan cooled) motor. Thus my explosion risk is minimal.

I decided to just recommend people should power their paint booths with a EXPLOSION PROOF fan. I am not going to recommend any particular fan.

There are no filters on my dust booth. Because I dump all of the dirty air outside. No filters to clean. No fume smells left over in the filters.


Making The Bottom

Photo: Bottom Parts Bottom Parts

Bottom parts, ready for assembly. I made my spray booth out of left over and scrap wood.

The base is 24" square by 10" tall. The top is 24" square by 30" tall.

Most spray booths are to wide and not tall enough to suit me. I wanted a booth made for a wood turner. We make things that are round thus we don't need a wide spray booth.

The bottom is made out of left over 1/4" thick plywood. I wanted the spray booth to be lightweight and easy to move around.

The nailer blocks were ripped out of scrap wood. They are 3/4" square. The scrap wood was an ugly dark color. I glued and narrow crown stapled everything together.

Photo: Bottom Sides with Nailer Blocks Bottom Sides with Nailer Blocks

I left a 3/4" deep ledge around the top of the bottom section. This will support a grill on top. I also cut a 4" diameter round hole in one side for a 4" dust pipe fitting.

Note: Latter I cut 3" diameter holes in all the corners to make the booth easier to pick up and move around. (See first photo above.) I did it with a big hole saw. If you want those holes and you don't have a big hole saw then you should probably cut them now.

Photo: Bottom Sides Assembled Bottom Sides Assembled

It is pretty flimsy at this point. It needs a bottom to make things sturdy.

Photo: Bottom Installed and Air Duct Bottom Installed and Air Duct

After installing the bottom I used plywood and nailer blocks to form a 4" tall air duct in the middle. I want to suck the air out of the center in the bottom.

I had to slant things up at one end to make room for the dust fitting to fit over the nailer block. If I did this again, I would make the sides 1" taller. 24" square by 11" tall. Rather than 24" square by 10" tall.

Photo: 4 4″ Dust Fitting

I also installed a 4" dust fitting in the side. I glued it in with some construction adhesive.

Photo: Top on Center Duct Top on Center Duct

I added a plywood top to center duct and made it airtight with construction adhesive and duct tape.

The opening in the center is roughly 4" square. Note: On the left in photo there is a piece of plywood I was test fitting. See next photo. It is covering up the partition visible in previous photo.

Photo: Air Baffles Half Installed Air Baffles Half Installed

I want my paint fumes to be sucked down in the center. Here I have installed 2 of 4 air baffles. Made out of 1/4" plywood. The corners were notched to fit around nailer blocks. I stapled them in via some nailer blocks under the plywood on the sides. I decided that just butting them up under the nailer blocks on the tops was the simplest solution. Latter I will seal things with duct tape.

Photo: Air Baffles Completely Installed Air Baffles Completely Installed

Cutting the 2nd set of air baffles was easier than it looked. I just measured the width at the top and bottom in previous photo and drew a straight line between the widths. Then I cut them out and fasten them in with some drywall screws.

Photo: Duct Tape to the Rescue Duct Tape to the Rescue

I made everything air tight with duct tape.

Photo: Center Baffle Center Baffle

I want my paint fumes to be sucked down around the outside. If I just have a hole in the middle then this is not going to happen. I installed a baffle in the middle to make things happen the way I want.

I installed the center baffle with some blocks at ONLY the corners and drywall screws. The slot opening between the baffle and slanted walls is roughly 1/4" wide.

Photo: Top Grill Support Bars Top Grill Support Bars

I installed some 3/4" square nailer blocks across the center to support a grill.

Photo: Turn Table Test Turn Table Test

Here is my turn table ready to go. I was going to leave things like this. But, latter I decided to install a grill. See photos near end.

My turn table is a lazy susan bearing between two chucks of 1/4" plywood. It is 11" diameter. I made this turn table a long time ago. Today I would just order a cake decorating turn table on Amazon.



Making the Top

Photo: Top Roughed In Top Roughed In

The top is 24" square by 30" tall. I made it out of left over 1/4" thick plywood and 3/4" square nailer blocks.

The top is removable. To make things easier to move and store. The top just sits on the bottom. The top is registered on the bottom by the uprights that stick down into the 3/4" deep ledge on the inside of the bottom.

I roughed in the top with clamps. Then I removed the clamps one by one and installed glue and crown staples.

NOTE! Latter I am going to cover the sides with 1/4" foam board. If I had this to do over. I would leave out the plywood on the sides and back. I would just use foam board fastened on with sheet metal screws.

Photo: Close Up of Roughed In Top Close Up of Roughed In Top

Here you can see that leaving a 3/4" ledge all the way around the inside of the bottom made my life easy. I just clamped the uprights in place and then added the plywood sides.

Photo: Close Up of Top Front Close Up of Top Front

The front is open. I cut corner braces into the plywood on the top of the front opening.

Photo: Added Sheet Metal Screws Added Sheet Metal Screws

I decided my glue and crown staples were not going to last long. I added some sheet metal screws to all the joints on the top for insurance.

Photo: Top Frame Top Frame

Here is the top frame. It is easily removable from the base. It just sits on the base.

Photo: Top of the Top Top of the Top

I covered the top of the top with some scrap 1/4" thick white plastic cardboard and duct tape. They sell white plastic cardboard at Home Depot, etc. 1/4" white foam board would also work.

Photo: Covered Sides Covered Sides

Originally, I was going to cover the sides with clear plastic sheet. To keep things lightweight. Then I remembered I had lots of left over 1/4" thick foam board from my days at IBM. I decided to go with the foam board, so I would not have to deal with plastic sheet flapping around.

Remember, my paint booth is connected to my big dust collector that vents OUTSIDE. Thus, I don't need any air filters in the sides or back.

Note: The picture on the outside of the foam board is a poster of a chip, that I helped design at IBM back in the early 2000's. We passed out the posters to IBM customers. The picture was cleared for release by IBM a long time ago.



Finishing Touches

Photo: The Inside The Inside

Here is a close up of the inside of the spray booth.

Photo: Add Grill Add Grill

I decided to add a grill. I made the grill out of 12" x 48" wire shelf from Home Depot. I cut the 48" shelf in half and notched it to fit in the corners.

Photo: Bottom Lights Bottom Lights

Adding GOOD lights was always a big part of my plan. I really want to be able to see PRECISELY where I have and have not sprayed.

I added Ikea Jansjo Led lights. I made these up a while back. 2 Ikea Led lights on a magnetic base. I added a chuck of metal to the front of base so I can move the lights around.

I have lights on the bottom and top. So there is no shadow under the piece where I can't see things.

Note: the Ikea Jansjo Led lights are NO longer available. I have not been able to find a good alternative in the US.

Photo: Top Lights Top Lights

The lights on the top are mounted on the inside via a magnet and a chuck of steel. See bottom lights in previous photo for more info.

Some day I may add a window shade to the top that I can pull down to trap more of the over spray inside of the booth. Thus I mounted the top lights on the inside. So, I can mount the shade on the outside.

Photo: Spray Pattern Cardboard Spray Pattern Cardboard

My plan all along was to add chunks of cardboard here and there to control how the down draft sucked the paint out of my spray cans. I don't want the down draft screwing up the spray pattern before the paint gets to my work.

In this photo you can see a piece of cardboard in front of turn table. So, far this has been all I need.

Photo: Ready To Go Ready To Go

Here is a piece ready to be sprayed. Good light top and bottom.