When does paint spray become "Non-combustible"?

[tlmartin84]

I guess this is a question for a chemistry guy.

When spraying, when is the material no longer combustible?

Is it when the particulates are removed from the mixture in the filter?

You can still smell the paint vapor exiting the fan, is it combustible?

 

[aptdweller]

It depends heavily on the paint. A zero VOC water-base paint is non-combustible by nature.
For a paint with VOCs, it is really when it is completely dried and the VOC level in the air has gone to zero.

What exactly do you mean by combustible though? I don't think you are going to get notable LEL levels unless you are using gallons of paint in a small enclosed area.

 

[sberry]

It should never be combustible in this sense. The fuel air mix should never be rich enough to ignite as a vapor. A couple box fans with HVLP or small gun is enough, on a semi with a couple guys going with paint pots it takes more air so it never becomes rich enough to make an explosive mixture. The word you may be concerned with is explosive vs combustible.
I am sure if one looks hard enough could find a case of booth fire, an explosion very rare. Its usually sloppy *****'s spill everything everywhere and the only case I actually have some semi direct knowledge of was where a couple guys got loaded and decided to warm paint over a wood stove and spilled it etc.
(See above post) ha

 

[maxpower_hd]

It will be different for different paints and mixtures. The smell isn't a good indicator. It is the concentration of the flammable vapor itself that determines the flammability. Some paints are much more flammable than others. Toluene for example can smell at very low concentrations even if below the LEL or LFL.

What you need is the MSDS or now called SDS to determine what the LEL and UEL are. Those are lower and upper explosive limits. They are also sometimes referred to as LFL and UFL for lower and upper flammable limits. Basically the air can have too low or too high a concentration of flammable vapor to burn. The issue is you have no real way to monitor that at home. You need a special meter to determine those. That's why excellent ventilation is necessary. You want plenty of air exchanges to keep those levels as low as possible.

 

[tlmartin84]

The reason this was asked is in direct correlation to the box fan mentioned above.

Guys use different home setups, belt driven fan, box fan, regular industrial fans, etc. They have been doing forever with no problems.

Hence the question, does/can the normal filters remove enough of vapor?

Charcoal filters remove 99.8% of all vapor, (or are supposed to).

So that being said, would it be an issue to have an open flame, brush spark, whatever on the other side of a plain filter, how about a charcoal filter?

 

[aptdweller]

One of the cases used to illustrate combustible safety was a case where someone painted a basement (oil paint) and the furnace caused an explosion.

What do you mean by remove? Are you using a spray booth?

I don't think you have a high risk of an explosion, but some details of what you are doing might help. Were it me, I would be looking into explosion proof motors.

 

[tlmartin84]

Yes a spray booth.....In another thread I posted an "air scrubber".

http://www.shop-pro.com/

Basically it uses charcoal and normal filters to clean the air before dumping it back into the booth.

I am debating on building something similar for my booth, it would elimate any vaccuum from my main shop, and would not **** all of the warm heat out.

It seems like a good idea.

I would also like to have some heaters in the room to speed up curing, any recommendations on heaters?

Which Sberry and some other guys posted on.

While exhausting outside is ideal, I would like to be able to circulate the air in the shop. Not only for heat/AC but for neighbors as well. Not that I think they would care, I am just trying to be as curdious as possible, and discrete as possible. I don't do it for a living, just occasionally.

The filters in this scrubber are supposed to remove 99.8% of all vapors.

Quote from the website:

"The most versatile prep station / booth on the market, the Mobile Work Station® is the certified EPA 6H compliant booth that’s perfect for adding capacity and flexibility to your finishing operations-without overextending your budget."

" Lab tests show the Mobile Work Station® – complete with multi-stage filtration and a patented recirculation design-removes 99.78% of paint overspray from the air, and carbon filters remove odors and VOC’s. It also eliminates the need for costly building and ventilation modifications, and dedicated shop space."



So reading that I assume any air that comes out of the top of that thing would not be combustible/explodable?

 

[theoldwizard1]

In "rattle cans", the most combustible part is the propellant. In a "well ventilated" area it will disperse quickly. The over spray from rattle cans drys almost instantly when it its the ground.

 

[DenisG]

It depends on the solvent. You want to be below the lower flammability limit. Above it is also safe [for flames and explosion] as long as it doesn't dilute and drop into the danger zone, but without breathing gear, you'd probably pass out:
http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html

 

[superfragl]

I painted my car in my garage this summer. I installed multiple intake filters and put a big box fan in the window. One fan was sufficient for extracting fumes/overspray out. I put a screen furnace filter in the front of the fan (I think AC/heat guys call it rock catcher) and that filter was completely plugged in 5 min and not letting any air out. I had to remove it. How long do you think your filters will last?..

 

[tlmartin84]

It is a filtering system, just like any autobody booth. You start out with a skin that is changed often, and then each progressive filter from there should see less and less.

Skins are cheap, the carbon filters were recommended to be changed every 3 months in a heavy use situation. Mine should last years...........

You have basically a vac guage on the box and as vac decreases you know it is time to change the particulate filters.

They say the carbon filters are basically good until you start smelling the fumes.......

 

[sberry]

The carbon filters don't last forever. I don't mess with them. You can buy filter media but for a dig the rock catchers are good. The point I make is there is a super difference in a daily paint shop and an occasional hobby job.
A guy can do good on a shirt tail here but you can't be commercial. Be courteous, schedule with good weather and be practical and fundamental. That beats perfect here.

 

[cwlo]

I can see that unit removing overspray, and smell, but how is it going to remove the solvent vapors and isocyanates? i don't think there is any work around to venting it out. Use carbon filters, and vent up out the roof if possible. Spray at night, or during workday when neighbors are not around. Check out autobody101 and southern polyurethanes website. A lot of good info.

 

[tlmartin84]

The activated carbon filters remove the isocyanates. There are activated charcoal filters, that the air passes through. They are 2" thick and contain granular material. Thos remove the chemicals, or are supposed to.

The final pleated charcoal impregnated filters clean up the smell as a final step.

 

[maxpower_hd]

With no fresh air turnovers I might invest in a cheap O2 sensor to make sure you have enough O2 for sustained breathing. lol

We use these at work in areas where O2 deficiency is a possibility.
http://www.pksafety.com/bw-clip-2-y...x0h9RuWj-wZ-qUgEAgu4Uq-yvQqv0FMTvsaAjoK8P8HAQ

 

[maxpower_hd]

And charcoal is very effective for removing just about all organic solvents. It does get saturated with time though so you have to replace them regularly. I am not familiar with that type of unit. The carbon filters we use, for both air and water, have pressure gauges on intake and output so you can see a change in pressure and determine when a filter changes are needed.

 

[tlmartin84]

I'm not dead set on this unit, I know that an exhaust fan is the easiest simplest thing to do, and no more than I am painting I can pay for a lot of wasted heat in the shop for some of the money I spend on this carbon stuff, but............

The hippie side of me says it would be good (you know, global warming, yadda yadda yadda). Plus I can see several other uses that make it attractive.

It is portable, I can roll it into my main shop, throw up a tent and paint a large piece of equipment. If I am doing a lot of welding in the winter, I can roll it into the shop and plug it up and filter the fumes. It just looks like for an overall application it would be a good investment.

 

[sberry]

A little experimentation with your layout, some prevailing winds, door openings etc and it may be as simple as adding a fan, a window etc. A good home brew booth should be in the hundreds not the 1000's and while its admirable to want to be eco friendly do I elsewhere not on a 1 off paint job.
You should post pictures to this setup.

 

[sberry]

As I eluded to earlier, this is something to apply the fundamental principles to not the latest technology.

 

[RossABQ]

...

The final pleated charcoal impregnated filters clean up the smell as a final step.

I'm surprised they don't have HEPA filters as the Final step, carbon filters spew out particles by their very nature.

Note that the system you've shown is meant to be used in the middle of a fairly large shop, that (presumably) has a good ventilation system with air turnovers spec'd by Code. In a small home garage, you don't have that situation, outside air needs to be added (a fair amount of it).

 

[94EG8]

We have something similar at the collision shop I work for. We mostly use it for when the preppers are priming something or sanding to keep the air as clean as we can for them. We occasionally use it for painting a small spot out on the floor but I wouldn't want to be doing anything close to a complete job with it. Get an exhaust fan of some sort and use exhaust filters in front of it to prevent the vapors and overspray from going outside.

That machine would work nice for welding though as you mentioned.

 

[tlmartin84]

A little experimentation with your layout, some prevailing winds, door openings etc and it may be as simple as adding a fan, a window etc. A good home brew booth should be in the hundreds not the 1000's and while its admirable to want to be eco friendly do I elsewhere not on a 1 off paint job.
You should post pictures to this setup.

Which setup are you referring to? My actual room?

If so I am currently wiring it.

Trust me, I am definitely not putting thousands into this setup. Like I said in the other thread, I have a ton of HVAC parts. 6 different size blowers, 3-4 motors to choose from and LOTS of random duct. Aside from the filters that's all I have in it. A total set of filters can be had for under $300.00. That would last me quite some time.

Now, If I have to purchase a shutter, and exhaust fan of comparable size I am looking at roughly 600.00-800.00 bucks.

Out of curiousity, do you guys think the system would improve if I were to duct the outlet to the back of the room? Have the intake on the front wall, and exhaust on the back at the ceiling? It would improve airflow....


Here is a youtube link to their products:

And their website:

http://www.shop-pro.com/

 

[tlmartin84]

I may just use a blower I have and duct outside. It is however for all intents and purposes much easier to not have a "paint booth" when it comes to insurance, inspectors, etc, etc.....

A big shutter and built in fan is kind of hard to explain....

 

[sberry]

You should be pulling air thru the existing building in to the paint room. The 1000's I speak of is also in labor. By the time you get it built could have been done with the thing you were trying to paint.
You need a simple room to booth conversion/modification, depends on where the start is this could be as simple as a couple hour job, less or ,,,,more just depends. Build a fan in the wall if you got to, doesn't take up much space and is simple.
You are way over thinking it for work at this level.

 

[sberry]

You want to pull from the other part of the building, this gives a chance to make some heat. It may be as simple as a wood stove or building furnace.
As for insurance no problem. Don't go out of the way to make it look like a booth. They would rather see something fixed up and neat.

 

[pcmeiners]

"I am debating on building something similar for my booth"

Hope you realize you will need a great of activated charcoal, which is not cheap, large bulk amount aren't too bad. You really can't re-activate it, as it would require a multi-process and steam. An exhaust fan and wasting some heat is your best bet.

 

[tlmartin84]

Building your own "tools/equipment" is part of the fun for me............I enjoy it.