Okay another question about homemade filter box and how many filters should i run.,

[Jakescc]

This is the quick crappy setup for now. Was thinking of building a filter box to run from the bottom of the fan all the way to the floor so the fumes and overspray will pull from the bottom of floor then up and out?
Any advice on size I should build and how many filters do you think I should use.
I mainly paint motorcycle parts here and there. Thanks

 

[sprint_9]

I had 4 on mine, I would say that would be a minimum. I always wanted to expand to 6 or 8 but never did. I suppose this is somewhat dependent on how much air you're moving as well.

 

['68 Coronet R/T]

The key to any homemade booth working acceptably is to calculate the cubic feet of air contained within your booth. Let's say you have 10'x12' booth with 8' high ceiling. 10x12x8=960 cubic feet of air. You should size your filter bank and fans to change that amount air every 2-3 minutes (for a home booth).

 

[Jakescc]

The key to any homemade booth working acceptably is to calculate the cubic feet of air contained within your booth. Let's say you have 10'x12' booth with 8' high ceiling. 10x12x8=960 cubic feet of air. You should size your filter bank and fans to change that amount air every 2-3 minutes (for a home booth).

Thank you very much. I was looking on how to covert all that. Much appreciated

 

[EddieF]

Privacy screen 3 or 4 foot (i forgot) roll across bottom, pvc strips screw/mount it to inside of door, and 2 more strips sandwich bottom of screen which just lays on ground. Could use neo magnets to hold to floor, i didn't.
It rolls up & little chains & hooks hold it to door when not needed. Guessing under 10lbs.
Does it still let dust in? Yes. Do suicidal bugs, grass, leaves ect come in? No.
However, exhausted air should be filtered as well to keep world happy.

 

['68 Coronet R/T]

I opted for a positive pressure set up. The fans draw air through open windows in the main garage area into a homemade plenum, then through the filters and into the booth. The air exits out the garage door that is raised just enough to create the desired pressure.
My system still needs refining due to some turbulence created by the squared corners on each side of the garage door but for the most part gives me a clean environment for painting. No clouds of over spray to deal with as you can watch them exit the booth while spraying. Living on 7 acres in a rural area prevents complaints from neighbors!

 

[mitch_04]

The key to any homemade booth working acceptably is to calculate the cubic feet of air contained within your booth. Let's say you have 10'x12' booth with 8' high ceiling. 10x12x8=960 cubic feet of air. You should size your filter bank and fans to change that amount air every 2-3 minutes (for a home booth).

So once you have cubic feet, how do you determine amount of filters needed? Is there a calculator somewhere that shows this?

 

[Jakescc]

I opted for a positive pressure set up. The fans draw air through open windows in the main garage area into a homemade plenum, then through the filters and into the booth. The air exits out the garage door that is raised just enough to create the desired pressure.
My system still needs refining due to some turbulence created by the squared corners on each side of the garage door but for the most part gives me a clean environment for painting. No clouds of over spray to deal with as you can watch them exit the booth while spraying. Living on 7 acres in a rural area prevents complaints from neighbors!

Have any pictures of your setup

 

[sprint_9]

I always thought it was 2-3 air exchanges per minute?

 

['68 Coronet R/T]

Have any pictures of your setup

I started with this but had too much turbulence. The air coming in was centered and too concentrated so over spray had a tendency to curl back toward the filters. Also there was not enough lighting.

One wall was plastic sheeting which easily let me know when I had the garage door adjusted for positive pressure.

I replaced the plastic with drywall and added angles to the long walls of the booth. Moved the overhead lights to the angled portions to improve lighting on the sides of the vehicle. I wish I had just added more lights rather than moving them and plan to reinstall some overhead lights.
I also added lights on the walls so as to help light up the lower portions of the vehicle.

Doubled the size of the filter bank to increase airflow and also doubled the amount of fans pushing air into the plenum (box) behind the filter bank. The filter specs have a flow rate to help you decided how many you need to facilitate the the airflow desired.
I am using squirrel caged fans from old home furnaces. They put out around 1200 cfm each and I have 4 of them.
Not saying may way is right or best by any means, I was never planning on restoring cars for other people, this was for my projects. So in my way of thinking I needed to move a "wall" of air from one end of the booth to the other, at a rate that changed in then entire mass of air contained in the booth twice per minute.
My booth is roughly 10x20x30' so 6000 cubic feet of air needs to be moved. 4 fans at 1200 cfm is 4800 cubic feet per minute but you have some flow restrictions with the plenum, filters and exhaust restriction to get a positive pressure. So a guesstimate puts me at 4000 cubic feet of airflow which changes the air mass in the booth every 1.5 minutes. Not quite what I was hoping for but a vast improvement.

I have since changed to LED 6000k frosted bulbs.

 

['68 Coronet R/T]

I always thought it was 2-3 air exchanges per minute?

You are correct. I should have reread my post more carefully.
Trying to build a homemade booth to get air changes of 2-3 times per minute is challenging and expensive. When I pushed the numbers it became clear that purchasing a paint booth would be an easier and more affordable option but was one that I couldn't afford at the time.
What I have though is way better than when I started and gives me some nice clean paint jobs.
I have new filters ready to go in before I get to painting anything again.

 

[Jakescc]

I started with this but had too much turbulence. The air coming in was centered and too concentrated so over spray had a tendency to curl back toward the filters. Also there was not enough lighting.
View attachment 12629
One wall was plastic sheeting which easily let me know when I had the garage door adjusted for positive pressure.
View attachment 12630

I replaced the plastic with drywall and added angles to the long walls of the booth. Moved the overhead lights to the angled portions to improve lighting on the sides of the vehicle. I wish I had just added more lights rather than moving them and plan to reinstall some overhead lights.
I also added lights on the walls so as to help light up the lower portions of the vehicle.
View attachment 12631
Doubled the size of the filter bank to increase airflow and also doubled the amount of fans pushing air into the plenum (box) behind the filter bank. The filter specs have a flow rate to help you decided how many you need to facilitate the the airflow desired.
I am using squirrel caged fans from old home furnaces. They put out around 1200 cfm each and I have 4 of them.
Not saying may way is right or best by any means, I was never planning on restoring cars for other people, this was for my projects. So in my way of thinking I needed to move a "wall" of air from one end of the booth to the other, at a rate that changed in then entire mass of air contained in the booth twice per minute.
My booth is roughly 10x20x30' so 6000 cubic feet of air needs to be moved. 4 fans at 1200 cfm is 4800 cubic feet per minute but you have some flow restrictions with the plenum, filters and exhaust restriction to get a positive pressure. So a guesstimate puts me at 4000 cubic feet of airflow which changes the air mass in the booth every 1.5 minutes. Not quite what I was hoping for but a vast improvement.
View attachment 12632

I have since changed to LED 6000k frosted bulbs.

Thank you i like that setup for sure.