I wonder... Cyclone as a spray booth ??? Crazy????

[Ken Shoemaker]

I was going to make enough small projects that it would be cost effective to spray the finish. My I was wondering..... If I built a booth about 36"HX36"WX24"D and put the connection to the cyclone in the top of the box, I could stack 3-5 pleated furnace filters on top of each other to capture the over spray. I am pretty sure no material would get into the dust collector. It shouldn't take long to know if the material would penetrate to the top filter and enter the cyclone.

To be clear, the box would have a place to put 3-5 pleated furnace filters between the booth and the blast gate. I could pull the bottom filter and move all those above down, then insert a new one at the top as needed. The power of the dust collector would certainly have enough power to move the air needed to acomplish the task.

I guess my question is "what do you think?" (And we're off!!!)

Ken

[Jeff Duncan]

First and most important question is are you going to be spraying flammables? If so then the answer is simply no. No amount of filters will remove the flammable vapors in the air.

If the answer is no, and your only planning on spraying water based then the answer is maybe. Understand the fans designed for spray booths and for cyclones are a bit different. In reality a box fan would likely work just as well without the expense. Cyclones, and dust collectors in general, are designed to pull a vacuum, whereas normal fans are designed to move a lot of air. I'm not going to pretend I understand any more than that, but I do know the fan in my spray booth is just a fan, (well OK, it's a little more than that), and the fan in my cyclone is an impeller.

Now your going to use filters to catch the overspray, but if you put too much filter in the way, your not going to get any airflow. Too little filter and your going to have a lot of overspray reaching your cyclone/fans impeller/blades. I maximize my airflow by going with the inexpensive fiberglass filters, they catch the bulk of the overspray. However I still have to open her up every other year or so to scrape out some of the build up. It's surprising how much does find it's way though the filters.

anyway hope this helps a little,
JeffD

[Peter Quinn]

I do not like it. You are introducing dust into your return air stream even if your DC filtration is highly effective. And even water based finishes have noxious odors the should be vented out of the spray environment and out of the fresh air you breath. If your finishes are flammable don't even consider this. A strong box fan is cheaper and more flexible for the purpose. I use a 15" tube gable fan in a wooden box as a vent with a channel to the out doors.

[David Kumm]

What you really want is a 1/2 to 3/4 motor driving a 12" tube axial fan ducted outside. I found some 12" rubber flex hose, put a flange on the end and attach it to the wall. I removed a couple of pieces of siding a couple of feet square that can be replaced and held tight from the inside. That system will handle a 3x5' set of filters. My filters sit on wheels about 3' high so they can be put against the wall when not used. Sawhorses and an old steel door serve as the base. Even in cold Wisconsin winters you have to exhaust outside. At least with the Sherwin Williams conversion varnish I spray. Dave

[Anthony Whitesell]

First and most important question is are you going to be spraying flammables? If so then the answer is simply no. No amount of filters will remove the flammable vapors in the air.

If the answer is no, and your only planning on spraying water based then the answer is maybe. Understand the fans designed for spray booths and for cyclones are a bit different. In reality a box fan would likely work just as well without the expense. Cyclones, and dust collectors in general, are designed to pull a vacuum, whereas normal fans are designed to move a lot of air. I'm not going to pretend I understand any more than that, but I do know the fan in my spray booth is just a fan, (well OK, it's a little more than that), and the fan in my cyclone is an impeller.

Now your going to use filters to catch the overspray, but if you put too much filter in the way, your not going to get any airflow. Too little filter and your going to have a lot of overspray reaching your cyclone/fans impeller/blades. I maximize my airflow by going with the inexpensive fiberglass filters, they catch the bulk of the overspray. However I still have to open her up every other year or so to scrape out some of the build up. It's surprising how much does find it's way though the filters.

anyway hope this helps a little,
JeffD

I was thinking the overspray will not settle out in the cyclone body, so it will get separated out by the filter. Eventually the filter will clog due to the overspray. A box fan and furnace filter would be much more cost effective.

[John TenEyck]

I've actually been thinking of trying the same thing, with a slight twist. My current homebuilt spray booth uses a 4 - 500 CFM blower and it does OK, but I can over power it when I spray really large objects. (Note: I only spray WB products and wouldn't consider using solvents w/o commercial equipment.) So I've been thinking of using my DC because it moves 1200 CFM. I really don't care if it's not as efficient as a fan specifically designed for spray booths. In my mind 1200 CFM is 1200 CFM and that's a lot more than what I have now. Now, here's where my idea may differ from yours. With my current set up, I exhaust directly to the outside, with no filters in front of the fan. It gets marginally coated with overspray, but that falls right off with a brush. So I plan to do the same with the DC. I will bypass the filter bags and exhaust it directly outside. Whatever coats the fan isn't going to build up enough to impact its performance. As others have said, overspray could/would clog up the bags or pleated filter, whichever you have, and the VOC's even in WB products are not something you want to redistribute back into your shop/house. I really can't see any downside to this idea other than my shop will cool off faster. BTW, whenever I spray I turn off my furnace so as not to cause any draft problems should it want to kick on.

[Ken Shoemaker]

My thought was that several "pleated furnace filters", put in front of the inlet of the dust collector at the top of the booth, would catch all the overspray before it even entered the DC piping. Therefore, the only issue would be sending explosive vapor material into the DC. Since the DC uses an impeller, the expolsives would not be in contact with the electric (read; sparking) motor that stands on top of the impeller. The DC is simply vented outside, using no additional filter, as would be the vapors.

Personally, I would think box fans, and the like, would be far more dangerous than my proposal. As I understand it, the fan motor would be in the airstream along with the blades. Electricals in the vapor stream means trouble, that withstanding, I dont think I understand the box fan setup.

Thanks for all the responses. I trust you guys and need all the help I can get..... Ken

[John TenEyck]

Are you thinking of using this set-up with solvent based products? Don't do it !!! The flammable organic vapors will not be filtered out by the furnace filters and, if the concentration gets into the right (read wrong) range will cause an explosion with any spark, regardless of where it comes from.

[John Coloccia]

I thought about this briefly when I was going to use strictly water based products....I immediately decided that the last thing I wanted was to turn my cyclone into a wet/dry vac. All that moisture can't be good for it.

AND it probably won't move enough air either.

As far as for solvent use, you're really just begging to blow something up. I picked up my spray booth fan for about $500 brand new, I think. If you're patient, you can find one used for much less.

I did a lot of thinking about this in the last year. Eventually, I came to the conclusion that building a real booth was the only sane way to do it.

[fRED mCnEILL]

I use my dust collector on my small spray booth. I used to use solvent lacquer but now use wb. Works fine for both. What I did notice with the solvent was that on the plastic 4 inch elbow that connects the dust collector hose to the booth wall, it really got coated with a thick coating from the overspray and becasue it was a solvent it tended to soften or "eat" the platice elbow. I suspect that MOST of the solids in the oversrpray settled out there.
Thick I will look at the impeller to see if there is evidence of the overspray there but I suspect that normal wood chips and sawdust probably keep the system clean. Incidently my dust collector exhausts to the outside into a chip shed with sawdust for horse bedding.

[Ken Shoemaker]

Fred,

Do you use any type of filter before it goes into the piping??? I'm considering using the pleaded filters as opposed to the fiberglass filters. I think the pleated would catch much more overspray because you can't even see through them like you can with the fiberglass.

[Dirk Lewis]

I use my dust collector on my small spray booth. I used to use solvent lacquer but now use wb. Works fine for both. What I did notice with the solvent was that on the plastic 4 inch elbow that connects the dust collector hose to the booth wall, it really got coated with a thick coating from the overspray and becasue it was a solvent it tended to soften or "eat" the platice elbow. I suspect that MOST of the solids in the oversrpray settled out there.
Thick I will look at the impeller to see if there is evidence of the overspray there but I suspect that normal wood chips and sawdust probably keep the system clean. Incidently my dust collector exhausts to the outside into a chip shed with sawdust for horse bedding.

No offence, but I wouldn't think that was something I'd do to my animals. What if material is making it through to their bedding?

[scott vroom]

My thought was that several "pleated furnace filters", put in front of the inlet of the dust collector at the top of the booth, would catch all the overspray before it even entered the DC piping. Therefore, the only issue would be sending explosive vapor material into the DC. Since the DC uses an impeller, the expolsives would not be in contact with the electric (read; sparking) motor that stands on top of the impeller. The DC is simply vented outside, using no additional filter, as would be the vapors.

Personally, I would think box fans, and the like, would be far more dangerous than my proposal. As I understand it, the fan motor would be in the airstream along with the blades. Electricals in the vapor stream means trouble, that withstanding, I dont think I understand the box fan setup.

Thanks for all the responses. I trust you guys and need all the help I can get..... Ken

Don't assume that your impellar system is safe around flammables; static electricity can create a deadly spark. Standard box fans are also not a safe solution. If you're spraying flammables you need to purchase a venting system with a closed motor that prevents the fumes from coming in contact with the motor brushes.

[Jeff Duncan]

What's keeping the vapors out of the motor? In my mind it doesn't matter what type of cyclone you have, (short of an industrial unit specifically made for such a use), vapors are in the airstream and they could certainly get up into the motor. I just can't think of a single GOOD reason why you would want to try this with solvent based chemicals. Read the back of the can next time you pick it up and ask yourself why they put all those caution labels there?

There's always going to be a couple guys in the crowd that "have always done it that way", until they blow something, up then they scratch there heads wondering what happened

As for the box fan setup, that's specifically for water based finishes. It's a simple method of removing the vapors in WB finishes, and is a pretty common setup. I would recommend just as strongly you don't try that with solvents either.

JeffD

[Stephen Cherry]

Don't assume that your impellar system is safe around flammables; static electricity can create a deadly spark. Standard box fans are also not a safe solution. If you're spraying flammables you need to purchase a venting system with a closed motor that prevents the fumes from coming in contact with the motor brushes.

Um, it's an induction motor, there are no brushes.