How dangerous is this.. who else does it?

[Bill Webber]

The thread down below on spray booths has me wondering who else may be skirting danger in a home made spray booth. And, how dangerous is it really?

I have (had) two spray boothes, both similar in design. Both are in outbuldings. Both use a pair of 1500 cfm attic fans. The fans are mounted low to the floor. In one case, directly in the floor with filters in front. In the second case in a 16" x 9' board that sets under a partly opened garage door. Both building are fairly large with the smaller one being 16 x 24 feet,. Both provide large inlet air openings. I always shoot towards the fans and filters. I have no special lighting or inlet filtering. I'm obviously at natures mercy when it comes to weather, heat, cold and humidity (and bugs). I use lacquer based finishes.

The fans are mounted low, because "Most solvent vapors are heavier than air and tend to collect in low spots." Curiously, many commercial spray booths have fans overhead, with both inlet and outlet overhead.

I've been using this setup for 15 years... hobbiest activities, with no problems. So how dangerous is this? Anyone have any stories about people that blew themselves up? Anyone else have a similar set up?

Be safe!

[Al Willits]

Comm units exchange enough air that it probably doesn't matter where they are, where I used to paint at they were along one wall, in fact the entire wall was filters.
As far as safe, explosion proof motors would be a good start, but trying to make a OHSA approved spray booth might be more than what you want to spend.

When I was spraying motorcycles and such out of my garage I had the explosion proof blower motor and tried to use common sense after that.
No open flames, turning lights on or off, anything that might create a spark, I also made a paint booth design that allowed the exhaust blower to get as much of the flumes as possible.

Kinda depends on how much you want to spend.

Al

[Howard Acheson]

>> The fans are mounted low, because "Most solvent vapors are heavier than air and tend to collect in low spots." Curiously, many commercial spray booths have fans overhead, with both inlet and outlet overhead.


In fact, the newest thinking is for air to be moved into a spray booth from above and exitted from below. That way the fumes and overspray is directed downward away from the operator who tends to stay in cleaner air.

Just as with dust air filters, you always want the air pattern to be such that the operator in clean air. Avoid having the operator between the source of contaminates and the exhaust or air filtering device.

[Cliff Rohrabacher]

Tis prolly one of the reasons people go waterbased.

The tech is getting better.

I just tried some for the first time and liked using it and liked the result.

[Allen Bookout]

Like Bill I have always wondered how dangerous some of these setups are in reality. I have used all kinds of unapproved setups over the years with no explosion----yet. You would think that we would have heard more about actual exposions if they were as dangerous as the safety people make us feel. Anyone have any input with actual personal knowledge of accidents?

I am building a small booth now using an attic fan but am planning to only use water based products due to the fact that I do no know how dangerous using other products really is. To go with an approved booth you are looking at real big bucks that can only be justified with a full time paying operation that is out of the limits for a very small shop or hobby workshop. On top of that I do not think that they would be approved for residential areas where a lot of us work.

If I decide to use products other than water based I think that I will go ahead and use approved fans but will have to forgo the metal enclosure.

[Al Willits]

The idea for safety in a spray booth imho is to keep the vapor percentage below the lower explosive limit, old rule of thumb I heard was if you have to stop painting to see, your not moving enough air.
Make a pass and just before you start another one look up, see stuff hanging in the air, probably not enough airflow.
Not very scientific I know, but with most automotive finishes it seems to work.

Al

[Phil Pritchard]

I notice that no one has mentioned the need for sealed (i.e. explosion proof) lights, another commercial requirement.

[Allen Bookout]

Bill,

I failed to note that, like you, I have always had mine set up in a two car garage with a double door open on one end and a single door on the other end. I have sprayed enamel and two part urethanes but no lacquers.

[nic obie]

Bill,

I failed to note that, like you, I have always had mine set up in a two car garage with a double door open on one end and a single door on the other end. I have sprayed enamel and two part urethanes but no lacquers.

At the risk of getting the usual PC peeps here pissed...

I have sprayed many, many, many gallons of NC and CAB Lacquer in the same type of shop for more years than I want to admit. I do have a regular furnace squirrel cage type blower venting to two 8" ducts thru the roof. None of my lights are 'explosion proof' and I am sharing the space with a gas furnace and gas water heater. As I am lucky to live in a nice warm place, I just open everything up when spraying.

Listening to some here, you'd think just a couple of squirts with a rattle can will kill you.



Folks have been finishing kitchens the same way for decades.

[Jim Becker]

Safety is nothing to joke about, Nic. Yes, many folks do things that are not ideal...that's an individual choice. But that doesn't discount the importance of talking about the right ways to do things that preserve your property, your health and perhaps even your life...

[Allen Bookout]

Safety is nothing to joke about, Nic. Yes, many folks do things that are not ideal...that's an individual choice. But that doesn't discount the importance of talking about the right ways to do things that preserve your property, your health and perhaps even your life...

Jim,

I know that you are talking about the ideal and safety which is fine but the problem is that some of us cannot afford the right way to do things all of the time. For us it is either do it the way that we can or not do it at all. No way could I justify the kind of money that a certified spray booth cost not being a professional unless there was a great deal of risk involved. I do not really know what the risk factor is. From my own experience I just get the feeling that the risk is not very high when having pretty good ventilation.

The other thing that I find noteworthy is that so far no one has come up with an accident report and I have never personally know anyone that has an explosive type accident while spraying.

I guess that it falls into risk management. So, thinking in these terms I would like to see some figures on explosive accidents per some figure and the circumstances behind each accident. Lacking this type of report I would like to hear from some members regarding some actual accidents and their evaluation of the situation at the time of the accident.

[Greg Funk]

For us it is either do it the way that we can or not do it at all. No way could I justify the kind of money that a certified spray booth cost not being a professional unless there was a great deal of risk involved. I do not really know what the risk factor is. From my own experience I just get the feeling that the risk is not very high when having pretty good ventilation.

The other thing that I find noteworthy is that so far no one has come up with an accident report and I have never personally know anyone that has an explosive type accident while spraying.

If you don't know what the risk factor is how could you 'feel' that the risk is not high based on your experience?

First hit on 'the google' http://www.texas-fire.com/blog/?p=851 a man badly burned spraying lacquer in a kitchen.

I think I'll stick with water based finishes...

[David Rose]

I think there is more hazzard from breathing the fumes than from explosion. A few years ago someone, I can't remember his name at the moment, tried to light paint fumes and even solvent as it was sprayed through a normal fan. There was not enought concentration for him to ignite it even with a propane torch. The residual effect of the fumes on the body is another subject. Lots of painters have quit due to various health problems that they thought were related to painting.

David

[Phil Pritchard]

I'm not really worried about explosions, but I am woried about fires. From what I've read using motors which are not explosion proof is the biggest fire hazard, and once a fire starts in a spray shop it has lots and lots of accelerant to feed it. The commercial requirements for lighting and static earthing is because volume sprayers are at much greater risk of an explosion than the small shop, but the cost of enclosing your lighting inside boxes is pretty minimal, as is the cost of moving your light switches outside so that the arcing can't start anything. Incidentally if your extraction is up to par you should never have enough combustable mixture in the shop to start anything. And how many people here do woodworking or spraying in a shop where they don't even have a fire extinguisher, I wonder? You don't have to buy the industrial rated stuff at all, but it's always worth seeing how the big boys do things and maybe copying some of the safety ideas.

As someone else has stated, the biggest single danger is breathing overspray - but then who sprays without an adequate mask?

Phil

[Al Willits]

I suppose every post should start with, You need a OSHA approved booth or you may blow up.
Everything after that would be your taking a chance on doing your self in, that should keep everybody happy.
Now not having the space or money to do this, some of us have to compromise a bit.
You can not have a explosion if the vapors are below or above the explosive limits, ain't gonna happen, ask any fireman about the triangle, oxygen, fuel and heat need to be at certain percentages to have fire.
Least wises in the real world.

If you move enough air, the only place (never say only...I know) your liable to get that would be at the exhaust fan, move enough air and it wouldn't even be there.
The only reason I bought an explosion proof fan is another painter buddy had one of the two 1/2hp basic exhaust fans short out and the paint in the squirrel cage blower caught fire.
He does automotive painting for a living and probably paints more in a year than most of us will in a life time.

I keep hearing ya can never spend to much on safety, well I wished I had the disposable income some must have, but unfortunately I don't, so like a lot of the other people I know, we have to do the best with what we can, or just sit in front of the TV, other than rotting the mind, it's pretty safe there...
imho, this whole thing can be summed up with the word, airflow.
Well...that and a good respirator..
Al.....who's off for his second cup of coffee and will come back and try to figure out what he just posted....