Heating a Paint Shed

[xtremek]

Ok folks, I want to build a 8'x10'x8' shed, strictly to paint parts in. I live in mid-Michigan. 2"x8" for floor joists, 2"x6" walls and fully insulated. Probably a 20"x20" fan to pull out the fumes. How would you heat it? And no, I'm not worried about explosion proof whatever. I've painted in my current shop, using and siphon gun, and it has a propane furnace. I'm just tired of overspray on everything, and dirt in every paint job.

 

[Sumboodie]

A 20x20 fan for a essentially a large closet?

 

[gmcgeo]

Garage heater, 30 k or 45k btu separated combustion "fresh air in exhaust out" Modine. mr heater, renzor

 

[Yankeefarmer]

Ok folks, I want to build a 8'x10'x8' shed, strictly to paint parts in. I live in mid-Michigan. 2"x8" for floor joists, 2"x6" walls and fully insulated. Probably a 20"x20" fan to pull out the fumes. How would you heat it? And no, I'm not worried about explosion proof whatever. I've painted in my current shop, using and siphon gun, and it has a propane furnace. I'm just tired of overspray on everything, and dirt in every paint job.

The right way to do this is to establish your target airflow while painting. I have no idea what that should be, so let’s, for illustration purposes, say 500 cfm. Next, decide the coldest outside temperature at which you’ll be painting, and the temperature you want to maintain while painting (running the exhaust fan). You are now in a position, using the specific heat of air, to determine how big a heater you need.

Another consideration is what you’ll be storing in there to determine if you’ll be heating it 24/7 during the cold months or not.

 

[xtremek]

The right way to do this is to establish your target airflow while painting. I have no idea what that should be, so let’s, for illustration purposes, say 500 cfm. Next, decide the coldest outside temperature at which you’ll be painting, and the temperature you want to maintain while painting (running the exhaust fan). You are now in a position, using the specific heat of air, to determine how big a heater you need.

Another consideration is what you’ll be storing in there to determine if you’ll be heating it 24/7 during the cold months or not.

Hey Yf, thanks for the detailed response. It won't be heated unless I'm painting, or getting ready to paint. I'd like to be able to paint almost year around, so outside temps around 15*F. Paint cures best in the upper 60's, low 70's? The flow you're looking for would be the CFM of the fan I'm guessing, and a 20" Lasko box fan pulls about 1700 cfm. I'd have a cover over the inlet and outlet while bringing the building up to temp. I'm thinking I'll build it on those cement block pier things, and have R-19 in the floors and walls, R-38 in the ceiling, and regular venting in the in the attic.

 

[isb cornbinder]

Install a filter system that does not vent 100% to the outside. Any make-up air will have to be heated and this will add to your cost of operation.
For small parts, I use a cardboard appliance box with a metal grate near the top. I installed a kitchen range hood in the box as a down-draft. I vented about 20% to outside. I have painted red parts next to my black motorcycle. No overspray.

 

[bighouse01]

2 bathroom fart fans would probably work for your shed. If you move the air too fast your going to be spraying in a cold-wind!!

 

[FredWanaker]

I think it works like this. An 8 x 10 x 8 shed is 640 cu feet. If a 20" fan changes the air at say 1700 cfm the air will be changing just under 3 times a minute in the shed. At that size, to maintain a constant air temperature of 70-ish would require heating that 1700 cfm of air a minute from ambient outside clean air to whatever one wants it to be. I believe that is about the same size heater as a 2500 sq ft house if it gets down to say 15F outside there. But according to paint booth specs online the CFM should be 100 feet per minute for the face size of the booth. 8 x 8 x 100 is 6400 CFM. When the fan is on, can you ever heat it at that CFM?

How to Know CFM for a Paint Booth & Exhaust Fan Size

Why Paint Booth CFM is Important Paint booths are designed to meet a minimum air flow requirement to be compliant with national codes that govern spray booths. Important codes that paint booths comply with include National Fire Code 1, NFPA 33, OSHA, and a few others. For a good overview of all...

pittsburghsprayequip.com

 

[xtremek]

I figure I'll heat the "booth" up, get everything ready, then turn on the fans, then shut them off a minute or so after I'm done spraying. And I'm not going to have OHSA looking at my setup, just looking for something the is tolerable and won't let me die,.......quickly.