Art Anderson Posted July 5, 2014 Posted July 5, 2014 I simply picked up a pre-cut 5/8" plywood shelf at Menard's, cut that to the width of my sash window, then used a hole saw to cut the opening for a common 4" dryer vent. When I get to airbrushing, I merely open the window, insert this plywood plate (which has its dryer hose permanently attached, then close the sash down on it, which securely traps the unit. Works very, very well. Art
jwrass Posted July 5, 2014 Posted July 5, 2014 Allen, I'm in the HVAC industry and perform air calculation on a regular basis. 100 cfm will work fine. Use as much metal pipe as possible and try to say away from flex tube, I you have to use flex tube, the maximum length I would use is three feet and do not make any hard 90 degree turns. friction loss is much greater with flex pipe and you will move less air, consequently your booth will not perform as well, if you plan on spraying any type of flammable materials keep the motor out of the air stream as this could be a fire harzard. I personally would keep motor out of the air stream regardless jwrass
fitforbattle Posted July 5, 2014 Posted July 5, 2014 Does this work as a booth/instead of a booth? I have nowhere to drag an exhaust nor any hobby room. If the kitchen fan works, which colors work? I was thinking of just building a booth around the fan, with a floor and walls (no top if you catch my drift)
shift13 Posted July 5, 2014 Posted July 5, 2014 Allen, I'm in the HVAC industry and perform air calculation on a regular basis. 100 cfm will work fine. Use as much metal pipe as possible and try to say away from flex tube, I you have to use flex tube, the maximum length I would use is three feet and do not make any hard 90 degree turns. friction loss is much greater with flex pipe and you will move less air, consequently your booth will not perform as well, if you plan on spraying any type of flammable materials keep the motor out of the air stream as this could be a fire harzard. I personally would keep motor out of the air stream regardless jwrass Thanks brother I always do extensive research on almost anything I do. And the flamable and danger aspect seems to be more discussed than performance. Which is why I decided a blige blower. I would assume flex hose would be more turbulent but I dont think I can escape the 90 or 2 but from what ive read I should have atleast 18-24 inches of straight pipe from the blower before the 90? I am in a rented unit so venting out the window is inevitable.
Ace-Garageguy Posted July 5, 2014 Posted July 5, 2014 Running a bilge blower is probably a good idea, as the electrical components should be "ignition protected" to prevent sparking and causing the explosion that they are installed to avert, and the units are built to withstand over-heating and corrosion. BUT, beware some bargain-basement Chinese fans that aren't REALLY built to any kind of standard, and are just pretend-labeled "bilge blower". Also make sure your 12V power supply delivers sufficient amperage to run the motor without overheating. While it's unlikely that you'll ever get sufficient concentration of vapors to ignite in your exhaust hose, I've seen 1:1 paint booth fires (started by a spark in the exhaust ducting) that ended up destroying the entire shop and all the cars inside. I would also put your blower as close to the outer end of your hose as you can. It's been my experience that these things work better sucking rather than blowing.
shift13 Posted July 5, 2014 Posted July 5, 2014 Running a bilge blower is probably a good idea, as the electrical components should be "ignition protected" to prevent sparking and causing the explosion that they are installed to avert, and the units are built to withstand over-heating and corrosion. BUT, beware some bargain-basement Chinese fans that aren't REALLY built to any kind of standard, and are just pretend-labeled "bilge blower". Also make sure your 12V power supply delivers sufficient amperage to run the motor without overheating. While it's unlikely that you'll ever get sufficient concentration of vapors to ignite in your exhaust hose, I've seen 1:1 paint booth fires (started by a spark in the exhaust ducting) that ended up destroying the entire shop and all the cars inside. I would also put your blower as close to the outer end of your hose as you can. It's been my experience that these things work better sucking rather than blowing. Are you suggesting put the blower at the window instead of the booth? Luckily I saved my 13a supply from my rc addiction days lol
shift13 Posted July 5, 2014 Posted July 5, 2014 (edited) I know mine barely pulls in steam but just enouph smoke to not set off my alarm lol Edited July 5, 2014 by shift13
crazyjim Posted July 5, 2014 Posted July 5, 2014 Build it to accept a standard sized pleated air filter.
shift13 Posted July 5, 2014 Posted July 5, 2014 Kitchen fan? As on the ceiling? No way!!!I think he meant range fan above his stove. But yeah id say no and stick to the garage or great outdoors for now
shift13 Posted July 5, 2014 Posted July 5, 2014 Build it to accept a standard sized pleated air filter. thats the plan its soo much cheaper to replace and "should" catch most if not all overspray
jwrass Posted July 5, 2014 Posted July 5, 2014 Alan, I good rule of thumb is 10 x Dia of pipe before a 90 degree elbow at one tenth of a inch (W.C) static pressure in a low presure system and that is what you have a low pressure system. Yes turbulance is the factor you face with flex duct. I'm guessing your discharge is either 3 or 4 inch? If you have to use any flex keep it as taught as possible with 2 (or maybe 3) 90 elbows you should be fine any more than that 100 cfm at one tenth, is going to be at the limits. I know the topic always turns to DANGER DANGER, I doubt you would ever have a EXPOLTION with a fart fan as the likely hood of the motor windings seeing any true wet solvents with a spray cans or a airbrush are pretty unlikely. Does the hazard exsist? well sure. Best practice would be to keep the motor out of the air stream A 1:1 car booth fan is a whole different ball game as are kitchen exhaust fans say in a resturant. I have seen pictures in trade magizines as of what not to do and the destruction that has been caused by failure of these systems. 90% of the time it's not moving the air fast enough and poor or lack of maintenance. The only thing I know about bildge pumps is that I turn mine on before I run the boat to purge the hull cavity of any water and potential fuel vapors.
Miatatom Posted July 5, 2014 Posted July 5, 2014 Here's what I built. 100 CFM works great. Never any problem with build up of paint in the box/booth. http://www.modelcarsmag.com/forums/index.php?showtopic=76088
Ace-Garageguy Posted July 5, 2014 Posted July 5, 2014 (edited) Are you suggesting put the blower at the window instead of the booth? Yes, basically. You'll find it works much better to pull air through the filter than to try to push it. The filter is a resistance to flow, and trying to push air through it will just result in a "puddling" effect, with a lot of back-flow, and air coming at you from out of the booth, instead of being sucked INTO the booth, through the filter, and on out. It's also important to understand the differences in Miatatom's configuration and what you're suggesting. Tom's unit uses the filter to clean INCOMING air before if flows over the model, much like a "downdraft" 1:1 booth. Your configuration, if I understand correctly, is intended to use the filter to catch overspray and errant paint before you exhaust the air outside. REAL paint booths have filters to clean INCOMING air before it goes over the car, and also filters to clean OUTGOING, contaminated air before it's dumped back into the atmosphere. Edited July 5, 2014 by Ace-Garageguy
jwrass Posted July 5, 2014 Posted July 5, 2014 Not a good idea! If it's a propeller type fan blade worse idea, they don't move enough air.
shift13 Posted July 6, 2014 Posted July 6, 2014 You guys have been great. I never thought of placing the blower at the end of the line. I always thought with any 90 bends it would lose suction so to speak. Im going to shoot for atleast 100 cfm but ill probley go higher if it dont break the bank. Buy if I get over spray my wife is gonna shoot me haha Thanks to all with your tips Once im finally set up keep an eye out for my youtube videos If I can I plan on building a box stock every week and doing a review on how well it went together
jwrass Posted July 6, 2014 Posted July 6, 2014 Most applications have the filters on the return side of the air stream (suck side) Only special applications require filters on the supply side of the air stream (blow side) as to not contaminate the atmosphere also know as scrubbing. Their are many ways to scrub air, air filters being one of them.
jwrass Posted July 6, 2014 Posted July 6, 2014 Coming from the HVAC industry I'm not a fan of any type of flex duct(to much friction loss)however if you are going to use it this would be a text book example of how it should be done! gentle curves, short length.Nice work James!!!
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