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
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.
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.
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.
I also installed a 4" dust fitting in the side. I glued it in with some construction adhesive.
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.
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.
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.
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.
I installed some 3/4" square nailer blocks across the center to support a grill.
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
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.
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.
The front is open. I cut corner braces into the plywood on the top of the front opening.
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.
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.
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
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.
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.
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.
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.
Happy Customer
A Friends Booth
One of my students and friend made his own paint booth.
Here are the photos he sent me of his both. Along with a great comment. “No more holding my breath while I spray. No more worries about the finish freezing on me either. Thanks Carl”
His booth looks better than mine. He painted his up nicely and added a nice light.