Greetings –
I had previously mentioned a problem with overspray using a conventional gun spraying lacquer. Decided to pop for an explosion proof exhaust fan setup that finally got installed today! Man this thing moves a lot of air: 4000cfm+ at 1/8″ static pressure. I’ve mounted it up in a clerestory space above the shop midway along the center of the 40′ length of the floor plan. Had the wood stove going to take the chill off, turned on the fan, which is easily 15′ above the floor, and I could feel the draft after it had been running a few minutes. This is a “Jenny” 20″ direct drive axial fan mounted in a shroud that installs quite nicely within the 24″oc spacing of my clerestory truss framing. The motor is a Baldor, will check the HP if anyone’s that interested. But it works really well.
At least now I won’t have to be working in what was essentially a bomb waiting for someone to light the fuse!! (grin)
Replies
Dennis,
Where did you find the fan? Some where local, on line, or a chain. I drove stakes in the ground yeasterday for my new shop. It's 2400 sq ft with a 20x20 dedicated finish room. I figue while I'm building I should exhaust the spray booth right. It sounds like you've found a winner.
Brian
Brian -I did a web search on explosion proof exh. fans and came up with an outfit in CA. Tried again to get the link for ya but didn't appear right away so I'll have to dig out the paperwork to get the Co. name. Although you can search for 'Jenny exhaust fans' in Google and get plenty of hits. The outfit I bought mine from isn't the only source I'm sure. However the guy I dealt with was super customer oriented.One thing to note about this particular model, the Jenny 20" direct drive axial fan, is that the motor is capable of variable speed (I didn't pop for the VS controller, tbhough) and there are about 8 wires in the connection box that allow for hooking it up for high/low speed, intake or exhaust. I decided to hire my electrician to do the hook-up figuring if he fried the motor then he could buy a new one (grin)If you don't find joy through a Google search for this fan let me know and I'll look up the source where I got mine.
Great Dennis, I found it. Thanks for the reference. I'm starting to put together all the pieces over the winter so I can break ground and hammer it out once the ground thaws. It's going to be so nice to have a dedicated finish room. Brian
Brian -The Co. I got my Jenny fan from is Bowline Enterpriseshttp://www.bowlinent.com/vent/fans1.htmfor the particular page of the model I have.Now, I have to relate that after the electricians left I was doing some work in the shop, turned on the fan and it started up full speed. Then over the span of about a minute or so it began to slow down to almost a complete stall then would start up full speed again only keep repeating this cycle. I'm gonna call Bowlin today to see if they can debug the situation but I'm thinking the electrician failed to wire it correctly. As I mentioned this motor has about eight wires in the connection box to allow high or low speeds, intake or exhaust. Depending on which one you chose the wires have to be joined in a particular fashion. I'll probably end up fixing it myself. (dang!)[edit to report the motor "fix"]
Opened the J box on the motor and found one of the wire nuts connecting some of the jumper wires was a bit loose. Twisted it tight and it's working like advertized! Electrician was in a hurry I guess so once the starting capacitor got the fan going, as it dissapated the fan would slow down to the point where it would kick in again. Alls well that ends well.By the way, I was doing some stick welding in the shop and soon developed quite a cloud of haze from the process. Took about ten minutes to completely evacuate the space. But don't count on working in a heated shop with one of these!
Edited 11/18/2005 12:52 am ET by DennisS
There are actually two "workshop systems" being described here, a general shop exhaust system and a spray booth exhaust system. The big difference is:· The person who mounted the fan in the ceiling is using it to just suck air out of a room. The air will flow through the room from any open door, window, crack, etc. and multiple paths will form, mixing everything in the room. The reason the welding fumes don't clear is because they are being swirled around by all the different currents. The fan is doing a good job of pulling the air into the room, but it basically takes out arbitrary molecules.
· If you are building a spray booth, you need to define an extremely clear path for the air to take, and the straighter the better. In through the filters, PAST YOU, past the item being painted, through the final filters, through the fan and out the exhaust duct. Note the PAST YOU part--you want to be upstream of the paint at all times, including when you are mixing it. So, your mixing area should be in parallel with the item being painted, perhaps separated from your main stream by a simple wall or panel. By rigidly defining the path you are sure to draw out only the air that needs replacing, that which has mixed with fumes.Other things to remember:
Either fan system will take heated air or cool air, whatever comes along. You can spend lots of time heating a room, only to have that precious warm air get sucked out in minutes. The cool air may only chill you, but it can wreak havoc with the fresh paint.
And depending on how tight your shop is, you might draw air through unexpected and undesirable places, like down a chimney of a woodstove or back through a water heater chimney. Plan wisely so you can close those pathways before flipping the switch--make sure those appliances can be isolated with an airtight seal and create an inlet port if necessary.And wear that respirator!I painted custom bicycle frames for Fat City Cycles in Massachusetts.
Good luck with all,
Lawrie
Thanks, the make up air is a concern of mine. Still working that out along with the heating system. The plan right now is to draw air through a filter into the finish room from the shop (large heated air volume) and tempered air into the shop from the "unheated" wood storage room. I understand the difference you are pointing out, and appreciate you chiming in. Thanks for the point about the direction of the air flow as well.Brian
Hey Lawrie,
I have hammered two Fat City frames into the ground (or pavement). My road bike had a custom paint job.... Coulda been you huh?
I worked at Richardson Bike Mart in Dallas, Texas for ..... a long time and we sold a few of those frames. Of course we also carry Serrotta, which was tough competition.
Mike
Hi Mike,
I did the custom paint work for Fat City in 1986 and 1987, until I developed an allergy to Imron and had to quit. In 1992 I returned from working as a VW and Audi technician to be the production manager at Fat Ciy, and did that for the next two years until all was moved to Serotta. Funny twist - I left the cars because I thought chances of getting a job with VW were slim, yet that's where I work now (since 1998).
I still have my Chris Chance road bike that was custom built for me in 1980 and a Fat Chance Titanium mountain bike. Both wonderful.
I painted a bunch of bikes in the short time, and had a hell of a lot of fun.
Drop a line to my e-mail and we'll chat about bikes instead of these wood thingies (the other passion).
Lawrie
Actually, Lawrie, I didn't put a watch to the welding fume evactuation but I think it was somewhat less than the 10 minutes I stated. In any event it was a pleasure to be able to ventilate the shop as quickly as it did. My shop has a 40 x 24 footprint, 10' clear to the bottom of the truss rafters and it's open above to a double 3:12/5:12 pitch with a clerestory rnning the length of the space. So I've got in excess of 1000cf of volume to deal with.My exhaust system wasn't intended to function as a paint booth type of setup - mainly to be able to clear dust and such from the space as a whole, which it does quite well. And of course, once the fan's turned on, might as well turn off any heating system! (grin).No doubt therea are other suppliers and/or mfr's of like fans. The purpose of mentioning the Jenny product was to offer but one possibility. But one I'm keenly happy with.Also, I might add that when I discovered the motor was trying to run off the starting capacitor I called Bowlin, the retailer, for help in diagnosing the possible cause. Brad, the main man there agreed with my guess and was immediately willing to send me a new motor if it were determined that it was defective. They seem very supportive of their customers.I don't have much problem with my wood stove since 1) I won't be burning it when I'm spraying and 2) my shop is quite porous in the first place! (grin)
Hi,
Thanks for the replies.
I didn't want to suggest anyone was using the fans for the wrong things, I just saw two applications being discussed and didn't want the unexperienced to think you could do both with one fan.
If anyone is setting up a booth I would be happy to discuss basics, though we need to remember the most important words will be from the building inspector.
Regards,
Lawrie
That assumes that the building inspector has any idea what he is looking at! ;)
I use a natural gas radiant heater. Great!!!!!
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