Paint Both Design

[Mopar_Mudder]

Does anyone have and experience or knowledge in building your own paint both? I am making one that will be 18x28x9

My big questions are CFM for the fan and how much surface area do I need from intake and exhaust filters.

Want to do semi down draft, exhaust low on one end and intake high on the opposite end.

I read conflicting info on the cfm needed. Some say it is width and height of room x100, other say it is the surface area of your intake filter x100.

Other than premade booths I can't find good information or calculations on making your own.

 

[mrbill55]

A typical blow through (yours, even as designed, is still a blow through booth, sorry) paint booth will move at 50 SFPM (surface feet per minute across the floor), so you'll take your dimensions of 18x28, then times it again by "50" (IE: 18x28x50)to achieve the formula for the CFM, in your case will be approximately 25,200 CFM needed. In addition to this, you'll have to factor in the parasitic loos of the filtering material for incoming area. You'll use the same filters for the exhaust fan as well.

Oh, and most importantly, you'll need explosive proof fans for both intake and exhaust, same goes for lighting, I highly suggest LED "daylight" bulbs.


Bill S.

 

[Mopar_Mudder]

Was planning on just an exhaust fan, no intake fan.

 

[Riveteer]

I had to make one very fast with the simplest materials for a 20ft x 20ft x 10ft high room with one door and a few vents near the ceiling.

I used a large sheet of plywood to completely cover the doorway, screwed two 2ft x 2ft Walmart box fans to the plywood, cut out holes in the plywood the same diameter as the fan blades and put furnace filters on the intake side of the fans. I covered the vents with furnace filters too. This worked so well the current tenants are still using my setup 25 years later.

I tried putting the filters on the exhaust side of the fans but that did not work. Using only a single fan did not work either. I tested the system by spraying red paint near the ceiling vents and the fans quickly sucked it into the filters, with no paint escaping out of the room. I used duct tape to seal all the joints because I was spraying aircraft isocyanate paints that will scramble your brain if you breathe them and there were other people outside the room. Only downside is that I had to remember to have everything inside the room before taping the joints.

Lighting was a big problem. I had just one overhead light and for painting I needed many side lights. I went to harbor freight and bought a bunch of cheap little LED utility lights powered by AAA batteries that had magnet bases. I propped up a piece of angle iron against the wall and positioned the lights exactly where I need them. I was painting large airframe parts so I had to move the parts and my lights around several times. I put all the lights in plastic baggies to protect them from overspray. It actually worked quite well.

I also blew decades of dust off the ceiling and walls with an air gun and 120psi before starting the build, and kept the floor wet to minimize dust during painting. I used stainless steel safety wire to ground the parts to prevent static electricity from attracting dust or overspray. I wore a full tyvex suit with it taped to my boots and rubber gloves and used a pressure breathing mask supplied by a filtered air compressor.

 

[mrbill55]

Was planning on just an exhaust fan, no intake fan.

Again, explosive proof, and you'll need enough CFM for whatever you are spraying out, and painting for a quality final finish.

Bill S.

 

[ejwan]

I'm looking into making a booth and in the design stages. Sorry don't mean to throw this off topic.

I plan to get explosion proof fan 24" dayton off craiglist whenever it pops up once I am ready to commit. The major problem I want to solve is how to keep the 2k odor to a minimum. It would stink up the entire block with my push thru from positive pressure fans in the pass. It could be not enough cfm by design. Do most professional paint booth recirculate the air to remove the odor and vent after the overspray has been capture?

Thanks

 

[mrbill55]

. Do most professional paint booth recirculate the air to remove the odor and vent after the overspray has been capture?

Thanks

No, there are a series of paint related filters that are designed to capture the particles and keep them trapped as the air is exhausted into the atmosphere. Again, the filters are specifically designed for the automotive industry. Purchase these, add a secondary filter box/holder with another set of the same filters (intake and exhaust can use the same type of filter material) to cut down on any leakage you may have.

Important that you do not allow the fumes or airborne particles into the house or the area around you home, they are deadly and will be absorbed into your skin (called dermal absorption), get in to your bloodstream, lungs, etc....That is the last thing you want for you, your family, your pets, friends, etc....... Spraying paints is not like it used to be, the safer you are, the safer you set up your paint booth, the better off everyone around you will be.

Bill S.

 

[nadogail]

The Paint Booth at my last employer had an extensive filter system to allow only clean air into the booth and also trap all the paint in the exhaust.

I am not a painter but I did assist with the maintenance of both the ventilation and lighting systems of the Paint Shop.

 

[ejwan]

I purchased the 20x20 fiberglass green/white filter from my paint supplier. It was setup as one layer of filter for the exit side of the booth. Maybe I should try two stage filtration for the exhaust and this time it will be negative pressure instead of positive. The positive pressure may have contributed to gases escaping from a crack. Or it can possible not enough air volume to trap the particles.

I do everything as safe as possible within my control. I have a sas supplied air system with a full face hood