paint booth

Not sure on the theory except maybe the idea everything doesn't get drawn over the paint job ( dirt dust lint etc) from front to rear. It's also the latest trend in upper scale 1/1 booths. That's ok, I made mine up draft ( better fits my exhaust situation). But I'm a Polack so you might not want to pay any attention to that idea.

I built a downdraft once.  It DID draw junk down on the model. 

that is why my latest one is a semi-updraft one  Pulls air kind of up (filter is at a 30 degree angle upward.  Works very nice.

For what it's worth I am in the process of building a spray booth in a closet and have included a link below for the blower that I will be using for my spray booth. I have not used one of these in a spray booth before but it seems like a good fit. I am not fully converted to acrylic paints so combustable fumes are a potential issue. These blower motors are electronically commutated so there are no brushes to generate arcing. Also the PWM controler gives you a nice speed control capability. Also if you look at the specs the static pressure rating is fairly high which will help when factoring in flow losses due to ducting/filters etc. I will be using a straight run of 6" round galvanized duct with a 6" to 6" x 12" galvanized register boot to tie the duct to the filter box. Looking online I found multiple companies that sell filter media for larger spray booths at reasonable costs and I plan to use those trimmed to fit my size needs. I am definitely not an HVAC, paint booth or airflow engineer but I think I will be in the ballpark with a decent design for my needs. Since I don't completely trust my flow calculations etc. I will probably build a quick and dirty filter box/plenum out of cardboard and experiment with different filter opening sizes before building the real thing.

This is one way to do it and I am certainly not implying it is the best way. Ignorance is bliss so I am having lots of fun so far

https://www.acinfinity.com/hvac-home-ventilation/inline-duct-fan-systems/cloudline-s6-quiet-inline-duct-fan-system-with-speed-controller-6-inch/?gclid=Cj0KCQiAvbiBBhD-ARIsAGM48bzBlZ8tiwOEFQJBt1Frw0ujABT2zJ_CVh6EgHTlW63N7kPUghTpYIEaApVxEALw_wcB

There are more than a few folk on the fourm who have kindly shared how they made their own paint booths. If you use paint booth on the search function. I am sure you can find a lot of threads.

I've made both, my first was a down draft and yes it worked better at pulling fumes away it also was great at pulling dust down on the model too as Don has said. The last booth I built is not a full updraft more of a back pull. I'm getting ready to change the fan out on mine since it's extremely loud.

This is my DIY paint booth. It consists of two parts: the top spray booth and the bottom plenum.

The bottom plenum of the booth is made of 3/4" x 11" precut MDF. The bottom is 1/4" hardboard. The blower is from Granger. 

The 3/4" cleats supports the top of the booth and the fiberglas furnace filter.

The top of the spray booth is a plastic storage box that I purchased from IKEA. The wood frame is 3/4" x 3" precut MDF. I attached a course metal screen to the frame. I then cut an opening into the side of the storage box and fastened the cut side of the box to the frame. 

This is the blower. The electric motor is located outside of the  air stream. I bought a plastic dryer vent kit at Home Depot. The kit included a plastic flange which I attached to the blower. I used the flexible plastic vent duct that was included with the kit to exhaust the blower to the outside of the house. 

Back to the bench

For what it's worth I am in the process of building a spray booth in a closet and have included a link below for the blower that I will be using for my spray booth. I have not used one of these in a spray booth before but it seems like a good fit. I am not fully converted to acrylic paints so combustable fumes are a potential issue. These blower motors are electronically commutated so there are no brushes to generate arcing. Also the PWM controler gives you a nice speed control capability. Also if you look at the specs the static pressure rating is fairly high which will help when factoring in flow losses due to ducting/filters etc. I will be using a straight run of 6" round galvanized duct with a 6" to 6" x 12" galvanized register boot to tie the duct to the filter box. Looking online I found multiple companies that sell filter media for larger spray booths at reasonable costs and I plan to use those trimmed to fit my size needs. I am definitely not an HVAC, paint booth or airflow engineer but I think I will be in the ballpark with a decent design for my needs. Since I don't completely trust my flow calculations etc. I will probably build a quick and dirty filter box/plenum out of cardboard and experiment with different filter opening sizes before building the real thing.

This is one way to do it and I am certainly not implying it is the best way. Ignorance is bliss so I am having lots of fun so far

https://www.acinfinity.com/hvac-home-ventilation/inline-duct-fan-systems/cloudline-s6-quiet-inline-duct-fan-system-with-speed-controller-6-inch/?gclid=Cj0KCQiAvbiBBhD-ARIsAGM48bzBlZ8tiwOEFQJBt1Frw0ujABT2zJ_CVh6EgHTlW63N7kPUghTpYIEaApVxEALw_wcB

 

That is a lot of money for a fan.  I have a 120 cfm muffin fan, which costs about twenty bucks.  It is spark free and not that noisy.  If you get the right cfm I think a speed control is overkill.

The only problem with an updraft booth to me is, I like to have a light in the top- that is why I used the angled filter, but if you have the space around the filter a light might still be possible in the top.  My light sits on top of a plastic window so no paint gets into the light unit.  I use tear-off strips of clear plastic wrapping tape to keep window clean.

Lots of creative solutions here and it is fun to see different implementations for different requirements.

Don, I had built a spray booth in the past with a shaded pole blower rated at about twice the CFM of your muffin fan and for my situation was not that happy with the booth performance. Most muffin fans that I have looked at were down to about 50% of their CFM rating by about .2 to .3 inH2O static pressure. For my current application that would not work well at all. My present hobby space is in the middle of the house adjacent to the living area. That being the case, I decided I was going to need some decent fan flow rates and static pressure performance to achieve exhaust rates through the filter and ducting and still have acceptable LFM flow rates at the face of my booth. I am hoping to be able to use some of the good stinky stuff without having to use the garage, we'll see if that pans out or not. You are right about the speed control being overkill but it was the default configuration for that particular fan so it was just part of the deal. I did grimmace at the price for the blower but I have been saving money for, and looking forward to this project for quite a while now. Don't get me wrong I am certainly not saying you don't have a great/creative solution that is much more affordable. I am just saying that for my particular situation I believe I am going to need a fan with a higher flow rate and static pressure rating to be happy with my booth performance.

As I said I really enjoy seeing the creative solutions you have all dreamed up, keep them coming.

Gil.

Back to the bench

Lots of creative solutions here and it is fun to see different implementations for different requirements.

Don, I had built a spray booth in the past with a shaded pole blower rated at about twice the CFM of your muffin fan and for my situation was not that happy with the booth performance. Most muffin fans that I have looked at were down to about 50% of their CFM rating by about .2 to .3 inH2O static pressure. For my current application that would not work well at all. My present hobby space is in the middle of the house adjacent to the living area. That being the case, I decided I was going to need some decent fan flow rates and static pressure performance to achieve exhaust rates through the filter and ducting and still have acceptable LFM flow rates at the face of my booth. I am hoping to be able to use some of the good stinky stuff without having to use the garage, we'll see if that pans out or not. You are right about the speed control being overkill but it was the default configuration for that particular fan so it was just part of the deal. I did grimmace at the price for the blower but I have been saving money for, and looking forward to this project for quite a while now. Don't get me wrong I am certainly not saying you don't have a great/creative solution that is much more affordable. I am just saying that for my particular situation I believe I am going to need a fan with a higher flow rate and static pressure rating to be happy with my booth performance.

As I said I really enjoy seeing the creative solutions you have all dreamed up, keep them coming.

Gil.

 

Ah, yes you have more problems than I do.  My booth is on the wall next to an outside window.  I use 16 x 20 furnace filters for a low pressure drop.  And they are cheap, frequently on sale in spring and fall.  I do have to replace filter often- every few months.  I also have to replace cabinet walls (Adhesive shelf paper) because the flow is not fast enough to keep crud off cabinet walls.  But I do like muffin fans- quite, sparkproof and not terribly expensive.

Don, I really like your shelf paper idea! That's a great way to keep the srfaces from getting too grungy.