The biggest problem with any paint booth ( homemade or mfg. ) is keeping it safe. Whatever you decide on, Remember to have at least a five pound ABC fire extinguisher close. I use furnace filters to collect paint dust. Also keep filters replaced on a regular basis. The dust is very flamable and ignites very easy. Last would be a quality respirator designed for paint fumes. A respirator is only as good as the filter. Buy extra filters and keep clean filters in the respirator.[:)]
crownover,
Good tips! I would offer a couple comments:
- A spray booth is considered (at least in safety and health circles) to be an engineering control. With these controls in place, personal protective equipment (PPE) is not required. I would submit that if respirators are needed when operating a spray booth, there is something wrong with the ability of the spray booth to adequately exhaust the organic vapors generated during the painting operation.
- A respirator’s filters are certainly important, but without a good seal between the face and the respirator facepiece, the filters are useless. Masks should be regularly checked for cracks and tears in the facepiece, as well as ensuring that the inhalation and exhalation valves are in place and functioning properly. Regularly cleaning the facepiece in warm soapy water goes a long way toward preserving respirator integrity. Stay away from chemical cleaning of respirators, including the use of isopropyl alcohol. Alcohol dries out the softeners in the newer silicone rubber masks, and may cause premature failure of the respirator.
- When purchasing a respirator for painting, ensure the respirator is equipped with an organic vapor cartridge (usually a black color), and a paint mist prefilter. These respirators are normally sold in a paint configuration, and can be bought from Lowe’s, Home Depot, etc. for about $20.
Hope this helps.
Gip Winecoff
Believe me, it can happen!!!
Made my own spray booth from cheap thin ply. Wanted to keep costs to a minimum, so used a cheap extractor fan. Worked well for 2-3 months. Cleaning my airbrush one day,
BANG!!! End result, no eyebrows,burnt hands, and a booth on fire. You’ve guessed it, no fire ext’.
Now I use fire retardent ply, brushless fan and two filters in front of fan. And yes, I did go
to the expense of a large fire ext, which is within easy reach.
Perhaps this is a bit of “overkill” but once bitten etc.
Be safe guys.
P.
Wow, Pops!
I’m glad you’re okay. For a while now I’ve been reading about the dangers of using the wrong kind of fan, but this is the first first-hand account I’ve read of something bad happening.
Quick question, do you think it matters if you’re using acrylics vs. enamels?
Anyway, thanks for the warning.
Regards,
-Drew
Acrylics will not explode because they use a non-flammable binder.
Enamels on the other hand have a solvent base and are flammable.
Correct me if I’m wrong Gip. [;)]
Mike
I recently started to construct a better booth. I have used the box and blower and a simple window unit before. When I decided to construct a booth in my shed, my hobby shop recommended to check out this site. (http://modelpaint.tripod.com/booth2.htm) Klaus Raddatz gives some excellent info on how to calculate the required airflow, ductwork and types of booths. I was able to use a old cabinet frame and existing ductwork. I purchased a 5600 cfm shaded pole motor from Grainger for $72 Total parts and material was about $175. Hope this helps.
Mike,
I’m honestly not sure about the binder statement; I know that binders help stick the pigments to each other and to the substrate, but you still have to get it from point A to point B through some sort of solvent vehicle. In my experience, simply because a manufacturer says their paints are non-flammable (ie,Testor) doesn’t mean they won’t burn. Flammability and combustibility are based on “flash point”–the lowest temperature at which a material will produce enough vapor that in the presence of some ignition source it will flash (not burn). Flammable materials have flash points less than 73 degrees F, while combustibles are greater than 73. There are also some boiling point considerations, but for this discussion, temps will work just fine. So, out of the bottle (like for brush painting), acrylics are safer than enamels, which are indeed flammable. HOWEVER, once acrylics are thinned with, say, isopropyl alcohol (a flammable solvent) and put into an aerosolized mist through the process of air brushing or rattle cans, acrylics become quite flammable. The big difference between enamels and acrylics now is the vapor concentration in air and it’s relative degree of evaporation (volatility): it should take more acrylic vapors to flash than enamel vapors. Unfortunately, we have no way of measuring (at least economically) vapor concentrations in each and every spray booth, so we need to take the same precautions regardless of the materials we use (brushless fans, adequate airflow and ducting, correct construction materials, etc.).
But what if I’m just using water to thin my acrylics prior to spraying? Then the hazard is lessened substantially, and the only concern would be the type, concentration, volatility and flash point of the base solvents. Of course, these most likely would vary somewhat between manufacturers. But now you’re in the area of the unknown, so once again, the same precautionary measures (as above) are taken to prevent the unexpected uh-ohs.
One last thing, and I’ll shut up. Rattle can spraying is a little different than setting up an airbrush. First, solvent concentrations are considerably higher, since higher volumes of paint are used over the same time. Second, they are already pre-thinned to get the mixture through the nozzle, and third, the addition of propellants increase the product’s flammability. Manufacturers (at least the ones I’ve seen) typically use isobutane and propane as their primary propellants, although I have seen some carbon dioxide used, but only sporadically. Conclusion? Spraying with rattle cans is considerably more hazardous than airbrush painting, even with acrylics, given propellant considerations.
Sorry this was so long, but I hope this helps, Mike. If you have any questions, or if you simply think I’m full of it, shoot me an e-mail.
Gip Winecoff
PS This is all taken from a fire hazard standpoint. Stay tuned next week when we expose Barney to 500 ppm of methyl ethyl death and see if he turns from purple to green! (Health hazards are a little different animal.)
GW
Great post! Thank you very much.
-Drew
You’re welcome!
GW
Thanks Gip.
You 'da man! [;)][:D]
Mike
Johnstone supply has shaded pole HVAC motors with different exhaust port configurations for less than $50.00. Their web site is: www.johnstonesupply.com
This might help you get a blower a little cheaper.
Wroper
OK, I give…what is a “shaded pole” HVAC motor?
Gip
A wrong choice of words on my part Gip.
The “binder” I referred to should have been the word, “carrier” instead.
I was referring to what medium the paint pigment is suspended in such as enamel thinner, lacquer, etc.
Acrylics such as the Createx paints I use for T-shirt airbrushing are ready to shoot from the bottle and are non-flammable. I assumed the Testors and other brands of acrylics were the same. [;)]
Mike
Mike,
The Testor’s brand may very well be the same. It may be that they are using a glycol ether as their carrier, and as such, they may not be flammable or combustible. I am getting this desire to experiment to see if acrylics can be thinned at all with a water/antifreeze mix. It would certainly bypass the alcohol/flammability/exposure thing, and being water soluble, would help with negating surface tension in water.
Anyway, I cannot find any of Testor’s acrylic material safety data sheets on line. I’ve found plenty of their enamel stuff. I guess I’m just going to have to contact them and Tamiya for information so I can pass out accurate information to you.
Gip Winecoff
I can’t afford a $300-$500 commercial model and I won’t build one myself because I don’t trust the power and airtightness of home made models, not to mention the fact that running that air exhaust hose across the apartment and out the window is going to be a pain.
So I brush in the bathroom with the bathroom fan running. I use a cardboard box as my spray trap and I wear a respirator. Finally, I try to use acrylic paints as the least toxic and least stinky. A cardboard box will catch & trap the paint as good as a $500 spray booth. Of course, it won’t do anything to protect you from the fumes but the respirator and the fan ventilation do the trick. The bathroom becomes a gas chamber so as soon as you’re done leave the fan on, close the door and wait for an hour or so befor showering or something.
Inexerienced colleagues should realize that an airbrush shoots a very thin and very precise jet of spray. It’s not like an aerosol can or a body shop gun that sprays all over the place and into the face of the operator. A spray booth is recommended, but if you can’t get one don’t panic.
If you’d like to purchase a commercial model I recommend ebay.com because they always have listings. Just beware of some of the lamers who offer those booths for what appears to be a low price but they quadruple shipping and handling cost.
coldwar68 - If you really want to build your own spray booth - Check back two or three years in FSM - they had an excellent article on building a spray booth from wood -If you want to build one out of metal, see if you can find a copy of the March 1988 or 89 Model Railroader - Gordon Odegard had an article (with plans) for a metal one - I wanted to build one for years (always seemed that there was something more important to spend our money on, our kids for example) - After the kids got out, figured that I could build a booth for probably 80 to 100 bucks of materials - Then I lucked out and found a spray booth (used) in the hobby shop for a couple of bucks more than a new Dayton blower would cost me - guess which direction I went.
I have heard of at least one person who bought one of these abrasive blast cabinets from Harbor Freight and made it into a paint booth.
I don’t know how well it would work though.
Here is the info on it:
BENCHTOP ABRASIVE BLAST CABINET WITH LIGHT
Strip paint, polish and clean material. Portable enough to use on a workbench. 15VDC light provides viewing for intricate work. Includes rubber gloves, blasting gun with trigger, 4 assorted ceramic nozzles, dust collector port, hopper and screen. Powder coated.
115 Volts, 60 Hz
Required air pressure: 80 PSI, 5 CFM
Required hose ID: 3/8’’
Viewing window: 21’’ x 17-5/16’’
Working area: 18’’ x 22’’ x 11-1/2’’
4 nozzles: 4-1/2mm, 5mm, 6mm and 7mm
1/4’’ NPT air inlet
ITEM 38440-2VGA
$99.99
This one here is even bigger for the same price, but no light:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=42202
Mike
Mike,
I like the abrasive blast cabinet. [8D] The description says it has a dust collector port, so you still need to purchase an exhaust fan and ductwork, and somehow mount it to the rear of the unit. I also like the light. It is guarded to protect it from the blasting media, but by being so constructed, may be similar to a vapor-proof light. I wouldn’t use the unit without it being mechanically vented.
Gip Winecoff
Gip,
And your hands would stay clean with the built-in rubber gloves in the front. [:D]
The only problem I see is that it is a little small for those of us building 1/48 aircraft kits. I don’t think the B-17, B-29 or C-130 kits would fit in there. [:)]
It would be great for tanks and car kits though.
Mike
Harbor Freight carries a hobby paint booth (or at least they did). It’s 20" x 12" x 12", metal case, ducted fan, filters and has a ‘window’ on top for light. The SKU # is 44040 but I don’t see it on their website. I picked mine up at a local HF for a little over $60. They must still have them around 'cuz the local has one on the shelf right now.