Spray booth fan, do I really need to worry about an explosion?

You need 3 things to create a fire, heat, fuel, oxygen( normal air). All 3 are present in a fan however you also need the right fuel/ air mixture for fumes to ignite. Odds are pretty good if you can touch the fan motor bare handed and not suffer a burn you do not have enough heat. You are correct in thinking that there is a small amount of fumes that are expelled from an airbrush, by the time you build up enough consentration to ignite you probably will have passed out. One thing I would do is make sure the fan motor is clean and free of dust and lint, these materials can wick moisture from the air and create an arcing issue. I have painted both enamals and acrylics for years without an exhaust fan and HIGHLY RECOMMEND using one.

Some fans have commutators or brushes where sparking can occur.  These are the kind to worry about, even if they do not feel hot to the touch.  I always use the brushless AC muffin fan type.

 

As long as you move enough air that you don't exceed the LEL (lower explosive limit) of the vapors, you don't have to worry about sparks.  If you do exceed LEL, you need to worry about all sources of sparks, including static electricity.

Most AC fans have brushless shaded pole motors.

Don

(I unsuccesully tried to reply to a comment)

So will a brushless AC motor be good? I happen to have a blower used for an inflattable water slide lying around. I have no idea why they used a brushless motor but I'm 100% sure that it is indeed brushless. Moves a massive amount of air and provides great pressure, would be perfest for me since whatever I use will have to move air through 25 feet of flex duct.

That sounds perfect. As stated above the safer the better. IMHO if you achive the right mixture of air, fumes and somehow get a spark you would probably be overcome physically. THAT BEING SAID if you can safely exhaust fumes DO IT, lungs are hard to fix.

Just so you know: The motor you are using was never ment for continuous use.( it will probably burn out at a most "inopertune" moment.)

Seth Krumm

I happen to have a blower used for an inflattable water slide lying around.

Unless you are talking about the kind that are used for those "bouncy house's" .... like you would rent for you're kid's birthday.

In any case, you will probably never pump enough paint through a fan to cause a "major" explosion. A small fire .....maybe. (but not very likely)  Only if the fan has a defect.  But unless you're airbrush has a 5 gal. cup  i wouldnt worry about it. ( By all means keep a fire extinguisher handy..... I have been wrong ..... from time to time.)

 

littletimmy

Just so you know: The motor you are using was never ment for continuous use.( it will probably burn out at a most "inopertune" moment.)

 

 

Seth Krumm

I happen to have a blower used for an inflattable water slide lying around.

 

 

Unless you are talking about the kind that are used for those "bouncy house's" .... like you would rent for you're kid's birthday.

In any case, you will probably never pump enough paint through a fan to cause a "major" explosion. A small fire .....maybe. (but not very likely)  Only if the fan has a defect.  But unless you're airbrush has a 5 gal. cup  i wouldnt worry about it. ( By all means keep a fire extinguisher handy..... I have been wrong ..... from time to time.)

 

 

Nope, it's one for continous use :)

Why not buy an airbrush spray booth instead? I got mine for around $100 It comes with its own vent hose and fan with filter.

The motor in the blower of my spray booth is not in the path of the air flow. That means that the paint residue never contaminates the motor. 

I made my own spray booth with parts from Ikea. Go here:

http://cs.finescale.com/fsm/tools_techniques_and_reference_materials/f/18/t/171600.aspx

BlackSheepTwoOneFour

Why not buy an airbrush spray booth instead? I got mine for around $100 It comes with its own vent hose and fan with filter.

 

Exactly!  How much could you really be saving instead of buying a unit made for it. Why risk it and woder all the time if it is safe. Way to go Black Sheep!

My diy uses a large cfm capacity bathroom exhaust fan, with a 1.2m long hose attached, it works OK.

I used a filter in a attempt to stop larger particles of paint, but it significantly reduces the fans limited ability to extract the fumes, so It will soon be removed.

From memory the fan can move about 250-270 cfm, the ducting was old ac ducting.

I don't belive the cheap AB booth's will have suficient ability to push the quantity over the required distance, from my reasearch they use 12v computer fans that are pretty useless apart from moving air inside an enclosed computer case.

Good luck.

I've used a Dayton blower in my booth for years and never had a problem, even when using aerosols. I don't remember the proper term but it isn't an explosion proof version. Not to say that nothing could ever happen but it hasn't. Don't remember the number either but it's around 325cfm. There is a fellow named Klaus Raddatz that I knew from another message board that had instructions posted online for building your own booth but I can't find the complete article now. He had a formula for figuring what size fan you would need. It took into account booth size, ducting diameter and length plus bends or elbows. If you have a small booth, vented directly to a window then no, it doesn't take much to move air. But, if you have a larger booth with a longer run of ductwork it takes much more fan than you may think to be effective. If you have a long run to make then smooth tubing would be much better than flex hose. But, just my opinion.

This is the blower that I use in my spray booth. The motor is outside of the air stream so there is no chance of an explosion. I also use a filter in the spray booth. The filtered air is exhausted through an exterior wall .

 

damouav

I don't belive the cheap AB booth's will have suficient ability to push the quantity over the required distance, from my reasearch they use 12v computer fans that are pretty useless apart from moving air inside an enclosed computer case.

Good luck.

 

 

I disagree.

I thought you would.

damouav

I thought you would.

 

 

This response is unnecessary.

BlackSheepTwoOneFour

 

 

damouav

I thought you would.

 

 

 

 

 

This response is unnecessary.

 

That response was also anticipated.

Every try to push a quantity of air via a 26ft tube with a 12v computer fan...

Thought not.

damouav

 

BlackSheepTwoOneFour

 

 

damouav

I thought you would.

 

 

 

 

 

This response is unnecessary.

 

 

 

 

That response was also anticipated.

Every try to push a quantity of air via a 26ft tube with a 12v computer fan...

Thought not.

 

Savage!

No more or less than I recieved from that person in the past.

Any who, moving on.

I suppose I should have said this earlier, since it is a closer answer to the OP's question.  I have a nice spray booth, but I only use it when I am painting with rattle cans.  I do not use it for airbrush work- I just clear off the workbench a bit and work right there.

I agree that the amount of fumes from an airbrush is pretty small.  I don't think the thinners used with acrylic and even with turpentine (for enamels) is that dangerous in those volumes.  I am not sure about lacquer thinner, though.  I do try to reduce the volume of gases during the cleaning, however. I have a homemade "cleaning station" that traps the vapors of what I run through my airbrush while cleaning.

 

Don Stauffer

  I do try to reduce the volume of gases during the cleaning, however. I have a homemade "cleaning station" that traps the vapors of what I run through my airbrush while cleaning.

 

 

Hi Dan,

Would you mind describing this? I have long wanted to build one of these.

Thanks!

Chris

Compressorman

 

 

Don Stauffer

  I do try to reduce the volume of gases during the cleaning, however. I have a homemade "cleaning station" that traps the vapors of what I run through my airbrush while cleaning.

 

 

 

 

 

Hi Dan,

Would you mind describing this? I have long wanted to build one of these.

Thanks!

Chris

 

Well, I will have a chance to build a new one, so will take pictures while I do.  My cleaning station sat on the edge of the bench right below where I keep my airbrush.  I use a suction feed (bottle type) and the bottle adapter/bottle fell out when I picked up the airbrush day before yesterday.  It hit cleaning station on way down, knocking both to floor, and destroying my cleaning station.

As a summary, since it will take a few days to make a new one:

I use a glass jar (because I sometimes clean with lacquer thinner.  I make a necked top from 1/2 or 3/4 inch PVC pipe fittings, including a 45 degree corner fitting.  A very short length of pipe comes out of that fitting, with a piece of plastic covering the end. A 5/16 inch hole in the end is just a bit bigger than the tip of my airbrush.  I glue the pipe buildup in a hole I have created in the jar lid, and poke a little hole in the lid as a second hole, so the jar can vent pressure without competing with the incoming airflow.  Takes a glass jar (pint or half-pint or so) and about a buck or two's worth of pvc pipe fitting.

BTW, the station had several ounces of used thinner in it (which I save to put in my brush cleaning jar), and cleaning that off the floor was no fun!

 

 

You also forgot the 4th thing you need for a fire is static electricity I've been using the same fan in my paint booth since the early 70's have had no probluems. My fan motor is as far as I know brush type motor,It's the type used in furnace blowers. I can understand the concern here with all the new paints on the market that are no longer using a petroleumn base ie; lacquer base paints I think our biggest worry would be WEAR YOUR RESPERATOR when you spray.                        ACESES5