paint booth

Glad I could help Nailz.

Just remember that if you use enamels and clean your gun with laquer thinner the advice I gave does not apply.

Let us know how that booth comes out.

Mike

Excellent, thanks for the tip Mike. I guess I need to go get started on my new booth then. :)

QUOTE: Originally posted by Nailz I do primarily spray with acrylics, just wondering what you do to clean out your air brush when you are done, ie. what can you run through it that won't be flammable? I want to make sure I am safe with this thing.

Nailz,

You can clean airbrushes of acrylic paints with Windex or Formula 409 to go the cheapest route, followed by straight water. Both are not flammable.
There are other cleaners that work a little better but they are harder to find and more expensive.

Mike

naplak, I took a look at your example and I am thinking of building out my booth like this. I do primarily spray with acrylics, just wondering what you do to clean out your air brush when you are done, ie. what can you run through it that won't be flammable? I want to make sure I am safe with this thing.

Thanks.

What type of paints are you spraying with?

If you use acrylics exclusively then you don't need a squirrel cage fan, you can use any fan with a filter on it.
You can even use a 20" boxfan with a 20x20 furnace filter on the front and back to filter the air going through it.

If you are spraying enamels and laquers there are also brushless motor fans that do not produce a spark so the chance of a mishap is minimized greatly.

Here is a good article on booth design:

http://modelcartech.com/booth2.htm

Mike

I too started out using the cardboard box idea. For the fan I used a blower I got from a boat supply store. Blowers are used to remove any gasoline vapors that may have accumulated in the bilge of boats with inboard engines, so I figured it was perfect for spray booth use. A 200cfm blower was pretty inexpensive. The only problem was how to power it, since they are designed to run off of 12V boat batteries (similar to a car battery) - in other words, DC. One could use a car battery (but this brings up another problem - how would you recharge the battery?), but what I ended up doing was using an AC/DC converter I got at Radio Shack, so I could plug it into a wall outlet and convert the AC house current to 12V DC for the blower. A little complicated? What can I say, I'm an engineer, and had a little fun with it! After awhile, however, I decided the blower made too much noise. In the end, I came across the December 2000 article and built a more sturdy spray booth following that. I also highly recommend getting a fan from Grainger. I did, and it's a lot quieter than the marine blower, while moving more cfm. I think the Grainger fan was about $125, but well worth it.

Yes... but you have to be a little careful about flow ratings...

They are ratings measured with NO load, NO extra resistence, and NO ducting. SO your actual flow rate will certainly be less than rated. It is also affected by the area where air can flow into the hood.

A lower flow rate can work very well if you restrict the in-flow area, so you don't get fumes circulating back into the room. I do have some experience with Chem Lab hoods.......

Als remember that more flow can mean more dust going thru... I put simple window screen material over my in-flow area to filter some of the larger stuff....

For what it's worth - for years, I have used a home-made booth which uses a cardboard box. I got a squirrel-cage fan and a 120v motor, mounted them in a can that fit the fan impeller, cut a hole in the can to attach a dryer vent hose to the outside and cut a hole for the can to fit in a cardboard box. It worked well until I went to Harbor Freight Tools and found a booth for $50.00. Anyone wanting info on the construction, email me.

QUOTE: Originally posted by phesopheon Ray, who cares about the math skills. It's the modeling skills that really matter, eh? :-) Paul

Amen!! Just don't ask me to convert any scale measurements.

Ray

wow i had no idea so many people had great info, thanks everyone, sorry it has been awhile for me to answer. its hard to answer while at work. thanks again everyone

Thanks, Mkish. Those are some excellent suggestions.

Ray, who cares about the math skills. It's the modeling skills that really matter, eh? :-)

Paul

QUOTE: Originally posted by phesopheon I'm watching this thread closely, because I can't seem to get the right info either. Sorry, heylonghair, but I get 3255 cubic inches or 1.88 cubic feet when I do the calcs.

Whoa, you're right. I told you my math skills were finely honed. It looks like it's just going to be trial and error. I'll keep you up-to-date on how mine comes together.

Ray

Paul, looks like you and I were writing our messages about the exact same time. Take a look at my post above. I think it will clear some things up.

Basically, any fan will *work*, the question is will it work *enough* for what you want.

M.

I'm watching this thread closely, because I can't seem to get the right info either.

Sorry, heylonghair, but I get 3255 cubic inches or 1.88 cubic feet when I do the calcs. An article in the December 2000 Fine Scale Modeler said take the square feet of the opening and multiple by 100-200 to meet OSHA standards. The article cited an example of a 2 feet by a 2 feet opening requiring at least a 400 cfm fan. (It seemed to completely ignore the 200 end of things and went with 100 times the opening size). Then it claimed to add a bit more for resistance due to duct work, so the end choice was a 495 cfm fan. Some help.

I want to make a 3' x 2' opening, so that means I need at least 600 cfm and that ain't cheap. If there is any realism in this logic, then I just don't see how a range hood will work (although so many seem to swear by it).

You'd think this would be easier!

Paul

Ray,
Sounds pretty good to me. Problem is that I'm not really sure that I know any better than you do!! We'll learn together! Let's bring it up a this week's club meeting and we'll see what some of the other guys there say.

There is a 'formula' somewhere published by OSHA that lists their recommended cfm required for paint booths. I remember seeing it and this is the 'basis' for my estimate of 100-200 cfm per sq.ft of frontage. If I remember right, this was the minimum recommended air movement for commercial spray booths that would be used for painting lacquers and automotive-type paints.

Just to clarify, a lower cfm fan will work, but it just won't clear the area as fast. You might find that a 180cfm fan is fine for clearing your booth if you're airbrushing. But, start spraying a can of spraypaint and you might find that it isn't powerful enough.

Also, the filter you use and the exhaust path to the outside can dramatically affect the performance of the booth. Some filters drastically reduce the airflow, and the more bends and kinks you have in your exhaust hose, the harder it is for the fan to push the air out.

You have to make your own choices. Some people will put up with more fumes than others. Personally, my booth does an *ok* job, but I'm ready to pump it up and get some more power. I'm anxious to hear how longhair does with his motor, cuz that's the same one I'm thinking of buying. It seems that building a spray booth is just another modelling 'project' that most of us will go through. The end results will likely be as individual as any other model or kit we build.

Good luck.

M.

A fan like that would probably work ok, although it wouldn't clear the fumes as quickly or efficiently as a higher powered fan.

I am just in the process of putting together a paint booth myself and in one of my issues of Scale Auto mag I found an ad from North Coast Hobbies which advertises a paint booth that measures 20 1/2" X 14" X 11 3/4" and it comes with a 350 cfm fan. Now using my finely honed math skills :-) I came up with roughly 280 cubic feet as the volume of that booth. I would say try to get a fan that is at least equal to the volume of your booth or a little more.
I think the info that you came across would be more for just ventilation in a room or something like that. A paint booth is more a specialized application where you want to remove the fumes and stuff as quickly as possible.
As for the fan you found - cost may be a factor but nothing says that you couldn't get two and put two fans in your booth. That would be more than enough.
I don't know what kind of stores you have in your area but here in Canada we have a place called Princess Auto which is a industrial surplus store. They carry all sorts of things and they always have different fans and stuff for very reasonable prices. You might want to check around for something like that.

Well, mkish, how am I doing? Does that sound about right?

Ray

Hi all !!!!!!


I went to Lowes this morning tolook for a fan, and the most powerful one was 180 cfm.., no good???? I found this brochure from Broan, (fan manufacturer), and in it it gives this info ...... multiply the length and with by 1.1 ...... example... for a 6'x8' space it would be 6x8x1.1=52.8cfm

According to this calcuation, Mkish, in your example you would only need a 2.2 cfm fan!!! I don't understand!!!!!!!!! can someone please help????

coldwar,

Do some more research to get a better answer on the fan size, but my recollection is that you need 100-200 cfm for every square foot the front of your spray booth is. ie. if your booth is 2' wide x 1' tall, that's 2 square feet total. A 200cfm - 400 cfm fan would adequately ventilate this.

Lots of people use less powerful fans, but I think that you'll find that they are poor at removing the fumes. With significant air movement, there should be very little fumes noticeable.

Mine is currently underpowered (about 240cfm for a total frontage of about 2' x 2' (4 sq.ft)) and I'm planning to increase the fan size.

M.

What kind of pull do you need on the fan to get the stuff out? I know that a lot depends on the size of the booth, but can you give any suggestions on a general estimate? Thanks.

Jerry

Depending on how you build it, I would say the best place to put it is on the back and 90 degrees to the base. This makes it easier to place a cut up furnace filter. If you put it on the top you will have to come up with a way to hold the filter in place. On mine I just push it in the back and have never had a problem with it.

Stay away from bathroom fans. You run into the same problem which is getting explosive fumes into the spark of the fan. The motor needs to be isolated from the fan which is why all of the commercial systems you see use a squirrel cage fan like you would buy from Grainger. I know this is more expensive, but this will last you a life time. It's worth the investmen.

Good luck guys
Dave

The best place is wherever you have room to place it. I built my spray booth with the fan in the back, rather thatn in the top. Pulls paint spray and fumes from the direction of the paint flow from the airbrush's general direction when working. No problems with the sysytem,and I've had it about a year with steady use every week. -Ed

what is the best place toput a fan??? In the back of the booth or the top of the booth???

is it possible to use a strong bathroom exhaust fan???

That won't work guys... you gotta tell her that you don't want the bad smell of your model building to interfear with her perfume.
Only kidding Ladies, of course safety is the point here.

Madd Dawg

Yes... that those chemicals in the air will eventually be inhailed, or settle onto some surface where they attract dirt, or damage the surface itself.

46builder, this is an EASY sell! Getting all those fumes out of the house is huge! And a side benefit is that there is less chance for an explosion because the fumes will not get near a heat source in the house! It's certainly clear to me that you're doing this for her!
Dave

thanks for the advice, now just to convince the wife.

Here's a link to my page on how I made my hood...

I am about to build a new one, but this one was pretty easy with lots of premade parts.

http://www.naplak.com/modeling/tips/painting_hood.htm

I would highly recommend building yourself a good booth made from wood. I've had mine for many years now and it serves me very well. Be sure to get a good squirrel cage fan (available from Grainger) so that the fumes don't get into the motor. Considering the use you will get out of it you'll find it one of your best investments.
Good luck!
Dave