Paint Booths & Safe Ventilation?

[jbwelda]

one thing that no one has brought up yet is the possibility of planning your builds on a yearly basis. then do your painting during the wet and/or non-dusty season (there has to be one, right?) and your building the rest of the year. its pretty restricting, that's for sure, but it combined with spritzing down your paint area right before you paint could help you avoid the worst of it.

jb

[jwrass]

Seems I did address the problem of year round painting with my reference to a 1:1 booth. It's just like racing the more money you spend the faster you CAN go. I could easily put together, manufacture and market a enclosed climate controlled booth but who it going to pay upwards of $ 2000 to buy one. Maybe I should engineer one, draw the plans, put together a materials list and sell it!!!! A climate controlled booth can easily be done!!! No more waiting for weather (which is way over blown) what is that worth? Who knows?

[Quick GMC]

one thing that no one has brought up yet is the possibility of planning your builds on a yearly basis. then do your painting during the wet and/or non-dusty season (there has to be one, right?) and your building the rest of the year. its pretty restricting, that's for sure, but it combined with spritzing down your paint area right before you paint could help you avoid the worst of it.

jb

Our record rainfall for the year is under 5 inches, and that pretty much happened within 48 hours. It rains about twice a year, outside of that it is typically dusty. Some nice days, but if I waited for the dust free days, I wouldn't be accomplishing much. We don't experience seasons, or freeze thaw. It's death for 5 months and pretty BLAH_BLAH_BLAH_BLAH nice for the other 7. Minus the wind. In other areas of the valley, like 15 minutes East, it's perfect. No wind at all.

Seems I did address the problem of year round painting with my reference to a 1:1 booth. It's just like racing the more money you spend the faster you CAN go. I could easily put together, manufacture and market a enclosed climate controlled booth but who it going to pay upwards of $ 2000 to buy one. Maybe I should engineer one, draw the plans, put together a materials list and sell it!!!! A climate controlled booth can easily be done!!! No more waiting for weather (which is way over blown) what is that worth? Who knows?

I think I have it figured out, at least on a temporary budget anyway. The way my bench is positioned, i can place the artograph booth on top, then surround the bench with plastic from floor to ceiling with those Zip Wall things. If I need to take it down, it will all come down in a few minutes.

I don't like the idea of a visquene room inside my room, but for right now, it's the only thing that makes sense to be. it's the easiest to set up and break down.

The one thing I have not addressed is the heat. It's in front of the hottest window in the house and there won't be ac inside the plastic. I guess if it's sealed off, and I run the booth to clear the air, I can run a small fan to cool me down, or is that a bad idea to have any moving air in there?

Edited July 22, 2014 by Quick GMC

[jbwelda]

Cameron, you live out in Darwin or somewhere?

jb

[Quick GMC]

Palm Springs. It's not all like that though, It's certain areas where the wind funnels through, which happens to be exactly where I live, and where I work. I grew up a few towns over, which is just a 10-15 minute drive, and we never had wind issues.

Here is another idea. Building a Lexan box to drop down over the booth onto the desk. This way I can enjoy the AC, I get the spray booth I want and it's sealed like the blast box, but it's easy disassembled.

I hope you can make sense of this

Edited July 22, 2014 by Quick GMC

[Miatatom]

I have designed and sprayed in many 1:1 booths and I find Tom's design to be the closest thing to a real 1:1 booth out their ( great job Tom!!!!)

jwrass

Thank you very much, sir.

[howsthat1959]

I found this, which seems hard to beat for the money, but I am worried about the fact that it pulls the air down. It seems like that would be the worst case scenario if therected was dust present

http://www.amazon.com/Artograph-Hobby-Model-Spray-Booth/dp/B000KNFR2S

I have one of these and I'm not thrilled with it. It requires three filter mediums (charcoal mat, thick filter material and a thin cover over the works). I vent outside so the charcoal isn't needed but the other two mediums clog pretty quickly (the fans seem weak) and soon the solvent smell winds up in the room. Ultimately,the nature of the filters causes over spray to bild up on the walls and "roof" of the box which requires regular cleaning.The mediums require replacement and get pricey. I'm ready to junk this and start over.

[jwrass]

The Artograph 1530 is another fine example of a $ 400 exhaust fan!!! This is not a booth!!!!!

[Ironman63]

I'm looking to build a paint booth(3x2x2) and use 2 bilge blowers for the fans. For the power supply, would this be what I need:

DC 12V 5A 10A 15A 20A 30A Regulated Transformer Power Supply For LED Strip USA

http://www.ebay.com/itm/181284109670?var=480306974549&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 ?

Will I need one for each blower ( http://www.ebay.com/itm/200489271226?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 )? The blowers are 4A and use a 6A fuse.

If I only need one, should it be a 10A or something higher?

Electrical connections are not really in my wheelhouse. Any help is greatly appreciated.

Thanks!

[Pete J.]

I will give you a slightly different slant on this based on your problem. The primary purpose of a paint booth is to exhaust paint fumes out of the room. To do this they work like a vacuum and suck the air out and blow it out of the space. This is not your problem.

Your problem is that you want an environment with clean, dust free air so it doesn't wind up on your fresh paint. The ideal way to do that would be to blow clean, filtered air into a box and keep it slightly pressurized to keep the dirty air out. If you think this way then providing a slightly pressurized source of air for the box and a slightly lower volume(ideally identical) exit volume would do the trick.

Since you want to build it yourself I think a system that flows upward would work best. Perhaps a box with a fine screen mesh in the bottom to set your parts on would be a good place to start. Get a good HEPA home air filter(Honeywell makes some good ones)and attach it so it blows air from the bottom of the box. The do the usual exhaust fan style on top of the box with a variable speed fan to exhaust the air. A furnace style filter would work to keep wet paint particles from encrusting the fan.

When you set it up, use some visible medium, such as smoke to set the exhaust fan speed so that it is just taking all of the air that is coming from the bottom out. This way you have clean air coming in the bottom and just enough pressure to keep the dirty outside air from entering the box.

I don't have the same level of problem with that dirty of air but I kept getting bits in the paint. I build a box with a home filter in the bottom and a top that I could seal with exit holes for the air. In short, I have a very small clean room. It works well for me, but it does nothing to help keep the room free of paint fumes. I just open the garage and get a good breeze going for that.

[jwrass]

Quite the slant for sure, I don't know what you would call that contraption but it has no basis in fan laws or air flow laws

[Pete J.]

Quite the slant for sure, I don't know what you would call that contraption but it has no basis in fan laws or air flow laws

Oh? You have one fan blowing pressurized clean air into a box and one sucking it out at the same velocity or slightly higher. What laws of fans or air flow are being violated?

Edited July 25, 2014 by Pete J.

[Miatatom]

I use one from an old computer power supply. 10 amps sounds high.

[jwrass]

Pete,

I don't want to start a war of words with you however I respectfully disagree with most of your post! I work in the commercial HVAC arena (see my profile) and perform and design systems like this on a daily basis (Only not this small) Are you familiar with air flow terminology, the laws, the math and design of such systems? Their are many contradictions in your post. I like to provide the science behind my claims not opinions.

I have already provided much of the math and theory to the original poster through pms. He is well on his way to building a successful booth. I'm sure he will back my science.

[jwrass]

Mark,

I personally wouldn't mess around with the 120/12 volt set up, unless you already have the parts and pieces and money is a concern.

Fuses are installed in electrical system races (distribution) to protect wires from failure. Your fuses should be sized by the wire type and the size of the wire you use, also Maximum load in amps the wiring will see!

All of this information is readily available with a simple search.

[Pete J.]

Jim- I respect your professional opinion and I am sure that you gave the poster a good technically correct method of building a sophisticated system that will work for him. I reread your posts and mine and I probably did a poor job of wording my suggestions. I don't think that what I am suggesting is all that different from what you out lined. I have a "clean box" that I have been using for years to allow my models to dry free of dust and critters. It is simply a box with a Honeywell house air cleaner that has a HEPA standard filter. It blows well filtered air into the box and keeps the contaminants out and allows an air flow to assist in drying. Simple but effective. I have wanted to add a paint spray booth using a similar bottom half for a while but don't have the space. My suggestions were based on this.

I was suggesting using this format as a base with an paint booth type fan over the top with the airflow balance to keep from sucking dirty air in from the room. No where as sophisticated as what I am sure you can design, but similar principles. Perhaps you can suggest improvements that won't break the bank with expensive purpose built equipment.

Edited July 25, 2014 by Pete J.

[jwrass]

The Industry standard for moving air in a booth is measured in FPM 100 FPM (feet per minuet) velocity (Airspeed). Not CFM ( cubic feet per minuet) Air being moved cubed.

Fan Laws and airflow have direct correlations, Space, design, and application dictate air flow.

[Art Anderson]

It seems to me, in watching this thread, that far too much complicated advice seems to be the norm! Even though I live in HUMID Indiana, I too have had to put up with dust blowing in and around my house, back when I lived in a subdivision on the edge of Lafayette, which meant farmer's fields, with plowing and disking in the spring, the incredible dust of wheat harvest in July, and even worse with harvesting soybeans and corn in the fall, so I do understand dust!

For starters, a closed room seems but elementary to me--after all, who among us in this day of central heat in winter, central air in summer would put up with constant dust inside our homes?

Now I do understand that many modelers, due to the requests/even demands of spouses, have to contend with being banished to the garage for painting, but that's not a major problem, nor does it require (in my stupid, caveman-level engineering skills at least) a huge, technological solutions.

Just think of it in terms of how you would set up to paint a REAL car in a desert, or otherwise often dusty environment (and yes, back in the late 60's, I had to paint a Model A Ford restoration in my Dad's garage which was just one city block downwind of a HUGE gravel quarry) so in a way I know whereof I speak here!

Visqueen , the rolled plastic sheet that builders use for many and varied purposes, can be used to block off an area for a "clean room" in a garage--just use Duck Tape to hold it together, and tightly down to a clean concrete floor!. Blown in dust, that which is soil, sand, "earth oriented" dust, is heavy, and what might come in even around the tightest of temporary enclosures is HEAVY, it really does not float in still air, unlike say "lint"--no, it falls to the floor and pretty much lays there!

The most sophisticated "HVAC" needed to eliminate that is a freakin' vacuum cleaner, anywhere from the wife's Hoover to a Shop Vac--seriously! If paint fumes are a concern, well--there are any number of small spray booths available with an exhaust system--again, plain and simple.

If you must, a simple plastic spray bottle or two (like your wife might use to mist her house plants!) with just plain water will serve to "lay" such dust as might be on the floor--beyond that, a simple dust rag will do the trick--in my past life, in that subdivision garage back now 25yrs ago all these things worked!--so I do know whereof I speak here.

I'm not trying to denigrate any of the HVAC professionals here, but geez, KISS! (Surely you all know the meaning of that acronym?)

Art

[Pete J.]

Art, I agree with what you are saying, but I personally just don't have the space to tape off an area of my garage to paint in. In this case small is better, thus, the clean box. After all I am not painting a full size car, only a few model parts and having a small box to put the fresh painted pieces in and closing it up, uses less than a couple of square feet of space and keeps the stuff from settling on the parts.

[Ace-Garageguy]

To run your two, 12-volt, 4-amp fans simultaneously, you'll need 8 amps available from your 12-volt power source, and put a 6 amp fuse on the hot side of EACH fan.

I tend to over-engineer, as running with excess capacity sometimes keeps things from overheating and melting.

One simple rule-of-thumb is that total circuit load should be no more than 80% of circuit capacity. Based on that simple assumption, 10 amps on your power supply should be fine, but more amperage available is always better IMHO.

Run 14-gage wire to your fans from your power supply, and you should be OK. The wire is on the heavy side for what is done these days, but heavier wire is like running a slightly bigger water pipe or hose...it doesn't hurt anything, and it lets all the electrons squeeze through it easily.

A computer fan, again IMHO, doesn't really move enough air fast enough. Two bilge-blowers may be more that you need, however.

What is the CFM rating of your proposed fans??

Edited July 25, 2014 by Ace-Garageguy

[Ace-Garageguy]

if it's in a garage or utility room, dampen the floor an hour before you paint?

A good friend of mine paints full-scale $100,000+ sport aircraft in the desert (Kingman, Az., in the middle of a large hangar) and the wet-floor, painting in early morning, less-wind method works well for him. There's NO dust in his finished paint, but it ALWAYS requires wet-sanding / buffing.

There's an almost constant wind out of the south. I've painted a couple of projects there myself.

Edited July 25, 2014 by Ace-Garageguy

[Harry P.]

Maybe I'm missing something here... but wouldn't a polishing kit take care of any dust in the paint?

[Ace-Garageguy]

Maybe I'm missing something here... but wouldn't a polishing kit take care of any dust in the paint?

Part of the problem is the type and size of the dust. In painting aircraft in the desert where I worked, the dust was very sharp and hard...not at all like the wimpy, soft East-coast dust that sands and polishes out, usually, with no trace. The hard-grit in the desert can attach itself to your sandpaper and make a series of deep scratches, almost before you know it.

[Harry P.]

Part of the problem is the type and size of the dust. In painting aircraft in the desert where I worked, the dust was very sharp and hard...not at all like the wimpy, soft East-coast dust that sands and polishes out, usually, with no trace. The hard-grit in the desert can attach itself to your sandpaper and make a series of deep scratches, almost before you know it.

Makes sense. Yes, our dust here is very wimpy...

[Art Anderson]

Art, I agree with what you are saying, but I personally just don't have the space to tape off an area of my garage to paint in. In this case small is better, thus, the clean box. After all I am not painting a full size car, only a few model parts and having a small box to put the fresh painted pieces in and closing it up, uses less than a couple of square feet of space and keeps the stuff from settling on the parts.

Pete, I hear what you are saying, however, the space I have allotted to my spray painting (airbrushing) area is not much larger than a moderately sized walk in closet--in other words, it really doesn't take a 2-car garage to have room to paint model cars.

Art