Spray booth planning questions

I would not recommend using that fan, as it appears to sit in the direct line of airflow/fumeflow. If you can find a squirrelcage fan, like the one you linked to, but with the motor outside of the airflow/airbox, then that should be considerably safer.

As far as draft, why not consider a back-draft setup? This setup will accomodate a wide variety of disposable air filters, and it leaves your booth floor solid (without vent holes or filter to contend with).

I will build my spray booth in a few months.  I had the same problem looking for a fan.  I found this stanely Blower.
http://www.amazon.com/Stanley-655702-High-Velocity-Blower/dp/B0001BJDUQ

I got one from wall-mart for about 35$.  I am sure you can get this in canada. 

It will take a bit of duct tape and work but should work great.  It is a squirel cage fan so the motor is out of the way of the fumes.

I was thinking downdraft because of the reduced airflow requirements, high CFM blowers seem to get expensive rather quickly. Having said that, I don't necessarily have anything against a cross flow (ie, air enters from the front, leaves from the back, flowing aCROSS the workspace) booth, just some reservations about finding a suitable blower.

Edit: What about using 1 or more bilge blowers? They're spark proof, rated for ~230-250 CFM, are available in configurations that easily take 4" ducting, and aren't all that expensive either.

TragicNut wrote:

Hello, I stumbled on FSM through a google search while doing research on spray booths, and though I have found a wealth of information, I am still left with a few questions and would appreciate any insight that you can provide. I'm going to be receiving an airbrush (Iwata HP-CS) for christmas, and I need to build a spray booth in order to get any real use out of it for the next 4-5 months (yay for Ontario winter)... I'm planning on a booth roughly 18" deep by 18-24" high, by 24" which seems like a decently large size (quite frankly, probably overkill) for painting 28mm miniatures (Games Workshop figures), should I reconsider my dimensions? Keeping in mind that some of the larger vehicle kits can run up to ~12" in length and ~8" in width. With that said,I have been doing quite a bit of reading, and have arrived at the conclusion that I need roughly 300 CFM of airflow if I go for a 18" high 24" wide booth. Being in Canada (and not a business) I don't think I can order from Grainger, so I'm left hunting around for a suitable, reasonably priced, fan.Would this: http://cgi.ebay.ca/Fanstech-300-CFM-Centrifugal-Fan-Blower-Dual-Inlet_W0QQitemZ160305205284 fan work? The CFM seems to be high enough, but I'm a bit concerned about the fact that it doesn't seem to be a shaded pole design, though I will be spraying mainly acrylics for now I am contemplating experimenting with enamals at some point and would like a booth which would work for them too. I'm also trying to decide between going with a cross draft layout or a downdraft layout, I could easily accept raising my work surface by ~6 inches which would allow for a ~5 inch high plenum underneath. In general, which airflow layout is easier to work with?   Thank you, James

here's a couple thoughts on this subject:

* I was sorta thinking about building a new small spray booth, and what to do about the box came to mind. Well for anywhere from $25 to $135 you can buy a fiberglass tub already finished at Lowes. The one that really caught me eye was about $88, and had a four inch holes cut in the bottom (may need to be opened up some).

* up the asile from the tub they had bathroom fans of all different CFM's, and the enclosure would be easy to mount lights on the outside. It would be just about right for most 1/48 fighters (prop), but maybe a little too small for a 1/48 four engined bomber. Armor would be a perfect fit. The one I looked at was about 14" deep. Mounting the fan would be fairly easy with some wood risers on the back side, and I don't think it would be all that hard to mount a standard furnace filter inside the tub.

gary

TragicNut wrote:

Thank you for the suggestion of using a fiberglass tub, but I already have 1/4" plywood which I was planning on using (probably framing with 1x2 as needed for strength.)

the reason he idea came to mind was speed of assembly, and it seals well.

gary

And I'm still spinning my wheels on the design, as I have yet to figure out where to source a suitable squirrel cage blower from in Ottawa, Ontario. I'm guessing some quality time with the phone will be required on Monday.

I have also realized that going the bilge blower route will not be as cheap as expected, AC-DC power supplies are a bit more expensive than I expected, unless I want to try wiring up an old PC power supply to do the job.

Finally, I'm having second thoughts about materials, will 1/4" plywood really be strong enough, or should I look at 3/8" or even 1/2" plywood, or even go to solid wood like pine?

TragicNut wrote:

...Finally, I'm having second thoughts about materials, will 1/4" plywood really be strong enough, or should I look at 3/8" or even 1/2" plywood, or even go to solid wood like pine?

1/4" should be plenty strong. I built my spray booth from heavy cardboard and it's quite ridgid for its purpose, it has far outlived what was supposed to be only a temporary life.  It also has a large plexiglas window in the top for added light. Next time around, I'm thinking sheet alumium or perhaps masonite.

I'm still waiting on a response from Detmar regarding the flow rate of their blowers under restricted conditions, as well as the power draw. In the meanwhile, I have drawn up plans in Sketchup, for a downdraft booth. Note that I am planning on installing a sheet of acrylic or plexiglass over the front setup so that I can block off part or all of the front opening.

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