Help with spray booth fan and filter.
14 replies to this topic
Posted 06 January 2009 - 06:53 PM
I use automotive paints and I spray my clear coat, so keep that in mind.
I was told by a maker of spray booths that I would need a fan that was capable of doing 750 cfm. Where can I find a fan/blower for this?
Also what filter material do you guys use in your booth?
Posted 07 January 2009 - 01:42 PM
Iam in the commercial paint industry the size of fan that you use needs to fit the size of your area.750cfm is fine but the area would need to small.A company called Northland Tools sells small industrail fans from 12 to 16 inches,as for the filter material good ole blue furnace filters work great.
Edited by plt, 07 January 2009 - 02:02 PM.
Posted 07 January 2009 - 08:27 PM
I want one, I just don't know where to get one.
Posted 08 January 2009 - 03:00 PM
If your fan is MOVING 750 cfm, there's no need for an explosion proof motor. The concentration of the fumes will never get high enough to cause a problem. But just because it's rated for 750 doesn't mean it'll move 750. The hoses greatly restrict airflow, even big hoses, so keep that in mind. If you're building a booth and not just a fan to clear an area, the fan only needs to move enough air to keep the fumes from coming back out of the booth as you spray. If you can feela slight airflow in the window of the booth, you're most likely fine. And if you still get fumes out, try making the window smaller. What's important is the airflow in the window.
Try a local HVAC guy.......if they have an old furnace that they replaced, they'll probably give you the blower for free. That's what I used and it works great.
Building a Spray Paint Booth for painting fish carvings.
I did need to filter it though, as the dick nite's clear didn't dry before hitting the fan. As an afterthought, I just built a frame for the filter over each air intake and used furnace filters.
Posted 12 January 2009 - 06:14 AM
We must have a member with HVAC knowledge. Could someone post how to calculate cfm's, tube diameters and any thing else necessary.
True, a little knowledge is a dangerous thing, but surely it will be better than no knowledge. Lets face it, members are just going to wing it anyway.
If someone is going to take on this task, it would be better in a new thread, named properly, so that the information will be easy to find.
Edited by Vodkaman, 12 January 2009 - 06:15 AM.
Posted 14 January 2009 - 10:40 PM
500 CFM / sq foot of hood area at 0 static pressure will work. Granger has a 16" fan that would prob work for your application.
Posted 15 January 2009 - 01:40 AM
For some reason I could'nt edit my post.
Anyways I made mistake what I typed, its 100 CFM / sq foot of hook area. YOu can figure it horizontally of open area is good. Sorry about the screw up
Posted 27 January 2009 - 06:56 PM
i don't know if this will help u but i install hvac pipe ...
and mostly your cfm is 4'' 50 cfm
5'' 75 cfm
10'' 400cfm or a ton of air
Posted 30 January 2009 - 08:46 AM
Davemyway, thank you for the figures.
I did a few calculations with the numbers. Excluding the 10” pipe, because the numbers were not consistent and I would unlikely to require anything that big, the air speed through the pipe was roughly the same for all the sizes, averaging at 550ft/min or 6.25mph.
Therefore, it seems that these industry figures do not take into account complications like friction and boundary layer stuff. This is good for us, as calculating multiple booth layouts is going to be simple.
This information allows me to write a simple spreadsheet that can calculate the diameter of the main pipe and the air volume of the pump required. Of course this information is basic and should pipe lengths of more than a few feet are required, I am sure the data would need modifying to take into account losses. Never the less, a good guide.
Example: 4 inputs 4" pipes, run into 8" dia main pipe, etc.
Posted 30 January 2009 - 10:27 AM
Excellent link Dramone, just what I was looking for. Thankyou.
Posted 05 February 2009 - 04:18 PM
If I remember right these figures are good for up to a 30 foot run of pipe. Subtract 10 feet for any 90 degree bend put into the pipe. After that your CFMs drop significantly. (keep in mind I am trying to remember back 4 to 5 years since the last time I designed a duct system. I hoe I am remembering right.)