I know there are several threads covering this topic already (and I’ve erad them all), but I have a question that maybe I’ve missed the answer to.
I’m building a spray booth that, in design, looks like all the commercially available booths (with some personal add-ons and touches). Dimensions will be 24"wx18dx18"h, made from sheet steel. At first, I was considering using an in-line duct fan (8" dia., 500cfm), but after reading all these threads about explosions and fires, I’m thinking that maybe that’s not the best choice.
So, here’s the question; is this duct fan a ticking time bomb (I paint using 90% acrylics, but I can’t guarantee that I won’t spray the occassional alclad II) or are they safe. I never see any explosion proof ratings on them, but they also don’t say they’re not (look at the Home Depot website for model 3012 duct fan to see the fan in question).
If it’s no good, I’m considering a bilge blower, which, by design, should be explosion proof. I figure with a power converter to go from DC to AC, I can run it off of house power. They’re pretty inexpensive. Now I’ve just got to find one that has a high enough CFM.
I’ve seen bilge blowers with squirrel cage configurations rated up to 250 cfm selling for about $100 that would probably work for you, but my personal choice would be an AC powered blower motor with the same type of fan configuration.
This is a chance you simply don’t want to take. You made the booth out of sheet steel—why scrimp on the blower?
Other than the possible physical and psychological trauma of a fire and physical burns (Ever had a really serious burn? Very painful, for a very long time, plus the danger of infection.) the insurance headache could kill you. If your insurance company found out that you had built a spraybooth with an in-line motor not designed for flammable exhaust, how much money do you think they’d pay to repair the fire damage? $0.00000000000000000000000000000000, plus dropping your policy. [xx(]
AC/DC convertors are a dime a dozen. Just be sure you use one that can handle the maximum current drawn by two of the blowers you are thinking about using. Otherwise, you could have another fire hazard on your hands.
Thermally protected means that it will disable itself if it overheats. What you are looking for is a motor that is not in the air stream, like a squirrel cage configuration.
I built my own booth and use a kitchen hood for it. I ONLY spray acrylics through it, and have made sure I have a very short venting system to reduce the possibility of any explosions. I don’t recommend using anything other than the proper fan if you are going to use anything else but acrylics, and even if you do spray on 100% acrylics go the extra distance and get the proper fan. I’m seriously considering rebuilding my booth to a downdraft system and will be upgrading to a bilge style fan at that time.
DO show us pics of both the construction and completion of your booth!
I am curious. How do you plan to configure your exhaust ducting since you’re using 2 fans?
Given the size of your booth, a good single centrifugal (“squirrel-cage”) fan rated at around 325 cfm would probably suit your needs, and probably be more advantageous than trying to mount two separate fan systems. Trying to balance a two-fan system where your airflow is equally distributed between the two of them might prove problematic, unless you are willing to install a plenum, or at the least a baffle/diffuser. I’m in agreement with Ross: If you’re making your booth from sheet metal, and you’re concerned about your fans, it seems that plunking down a little more change for the right fan would be the thing to do. Plus, I’m assuming you want this thing to last a while. Although I haven’t seen the bilge fans you reference, $22 for a centrifugal fan somehow doesn’t scream “quality” to me; and I’ve seen a few fans/motors.
The bilge blowers are inexpensive because the manufacturer’s haven’t hit upon the idea of ripping boaters off the same way the cage blower guys do to contractors and DIYers. Bilge blowers aren’t centrifugal fans, they’re tunnel fans which may also account for the cheaper price.
A bilge blower’s one reason for existence is to remove highly explosive gasses from an enclosed area. If that doesn’t sound like the perfect fan for our application, I don’t know what does. As far as price vs. quality, even the absolute most expensive blowers are like $65 and then, that’s only through a few online vendors for the big name blowers.
So I figure 480cfm for $40 is one heck of a deal. A comparable pole blower (about 465cfm) can fetch anywhere between $175 and $250).
I figure a simple diffuser panel behind the filter should be simple enough to stablize the airflow and short length of dryer hose off of each blower to go right out the window will suffice for ventilation.
My only setback is finding an acceptable power supply. I need to find an AC/DC converter that has 2 12VDC outputs with 10-20A ea…
I’ll try to take pics as I gather parts and during/after construction.
Sounds like you have it pretty well thought out. Have fun building, and be sure to send along in-progress and finalized pics. I’m looking forward to seeing what you’ve come up with!
Going to check out the blowers in person this weekend. I’ve got a lead on decent power supplies. Just need to finalize my construction plans and I am set.
Well, I’ve done pages and pages of drawings and calculations and it looks like it’s going to cost me about $230 before tax and shipping (not every item has tax, not every item has shipping). I figure around $260 when all is said and done. That price includes all the metal, the blowers, the power supplies and the filters.
It’s not as cheap as some of the ebay specials, but it is built to my custom specs. And it’s certainly cheaper than the commercially available units…
Not trying to dissuade you, but before you spend all that money, and then have to assemble it all, check out www.dixieart.com They have a back-drafted Paasche booth 22 X 16 for $239 delivered, and an Artograph 15 X 20 downdraft booth for $219 delivered, and you don’t need exhaust ducting for the Artograph since it “scrubs” the air with activated charcoal before putting it back into the room.
Ignorant as I am, does the Paasche booth include the exhausting system? Hard to tell from the pic and description. I’m very new to this, so pardon my stoopid question.
But I have the same question as SteveM, it doesn’t say whether or not these systems come with blowers. I’d hate to buy one of these only to find out I still have to buy a fan system.
Does anyone know for sure if there is a fan or not?
I sent dixieart an email asking them if had included fans or blowers and what cfm they are rated for, so if I get a response from them, I’ll post it in here as well.
With all the air I’ll be moving, do I need those allergen filters or will a standard furnace filter suffice? I figure since I’ll be moving about 480cfm out the window, I wouldn’t need the allergen filter. Though I could see them being beneficial if I didn’t want to vent outside…
As far as I know, the Paasche, as well as their other booths, come as “plug and play”. For the Paasche, all you have to do is hook some flex duct exhaust hose to the fan, plug it in, turn it on, and have at it. You might want to check on what, if any, filters come with the booth.
The filters you want to use are paint filters. An allergen filter would work, but only if you’re exhausting air back into the room (a no-no). Furnace filters IMHO don’t provide enough surface area to capture the smaller pigments generated during airbrushing. I would tend to think that paint filters should be available for specific booth types through Dixieart. If not, paint stores should have what you’re looking for, except you may have to trim to fit your particular application.
SteveM, there are no stupid questions in regards to this stuff. Feel free to ask away!
Well, I heard back from dixieart. The paasch booth comes with a 240 cfm blower. It’s 22"x16", so 240cfm is dang close to the 244.4 (calculated (22x16x100)/144) cfm needed.
That’s really tempting to go with this one. It’s a bit cheaper than my plans, and it’s already assembled…