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D I Y, Air brush spay booth

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  • From: sandy, utah
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D I Y, Air brush spay booth
Posted by thortenney on Tuesday, January 11, 2011 3:31 PM

have any of you built your own spray booth? i am trying to figure what type of fan i can safely use with all types of paints? thanks for your help!


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Posted by jrbernier on Tuesday, January 11, 2011 3:44 PM

  I built my first one out of 3/4" plywood, with a range vent hood.  All of the experts told me that I was going to have an explosion due to 'sparks' from the motor brushes.  Ran fine for 15 years, until the motor died.  I am currently building one using a bathroom exhaust fan.  The motors are enclosed and most paint now is acrylic.  I bought the cheap one at the local Menards/Home Depot.  Don't waste $200-300 on those ones in the catalogs.  Do get a good lamp so you can see what you are doing!

Jim

Modeling BNSF  and Milwaukee Road in SW Wisconsin

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Posted by thortenney on Tuesday, January 11, 2011 3:59 PM

thank you jim! that is/was kind of my idea also,  but the guy i talked to at my local grainger store told me i would blow myself up and burn my house down, then he told me just to do myself a favor and buy one that is factory built.  im gonna stick to  my plans. thanks again.  thayne


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Posted by maxman on Tuesday, January 11, 2011 4:31 PM

thortenney

thank you jim! that is/was kind of my idea also,  but the guy i talked to at my local grainger store told me i would blow myself up and burn my house down, then he told me just to do myself a favor and buy one that is factory built.  im gonna stick to  my plans. thanks again.  thayne

Well, you can go ahead and do what you want.  Personally, I built a paint booth that was described in an article in the January, 1988 issue of MR.  The article was called The Paint Shop Spray Booth.  The fan used in that was a Dayton Electric model 4C445A.  This is a pretty hefty fan that was rated at 525 cubic feet per minute.

The opening in the front of the booth was 24" wide by 15.25" high, and they calculated that they would get an airflow of  210 feet per minute.  The goal was to get between 100 and 200 feet per minute.  After all was said and done they measured about 150 fpm. This number reflected the fact that they had a filter installed plus the duct work to exhaust outside.

The reason we need a booth is to get not only the fumes but any particulate away from our faces, and you should still use an appropriate air mask no matter what type paints you use.  And I almost guarantee that you will someday want to use a solvent based product.

I know that some folks here say they've used bathroom fans, range hoods, and so forth.  But I'm not sure any of them know what the actual airflow is.  Maybe it's adequate, and maybe not.  I don't know, but maybe they do.  I remain doubtful.

This paint booth topic comes up often, so you can do a forum search.  But watch what you read.  There was one individual that felt it was adequate to have his booth exhaust into the room, rather than outside.

If you are interested in reading about this topic by a non-model railroader, there is an interesting article about types of booth design and the various airflow recommendations at the following link: http://modelpaint.tripod.com/booth2.htm

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Posted by Railphotog on Tuesday, January 11, 2011 5:37 PM

One advantage of a high CFM fan in a spray booth is that it is very effective in drawing dust into the booth onto your freshly painted model.

I've used a bathroom vent fan in my booth for over 20 years now, seems to work fine.    The brushless/sparkless motor is in the airflow and so far all of the Floquil and other lacquer based paint I've used haven't caused a problem.

 

Bob Boudreau

CANADA

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Posted by richg1998 on Tuesday, January 11, 2011 7:57 PM

Below is another version. This guy has a lot of good links for other projects.

http://www.housatonicrr.com/FoldingBooth.htm

Rich

N

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Posted by modelmaker51 on Tuesday, January 11, 2011 8:17 PM

I'm a custom painter  and I've been using a bathroom fan for 25 years, I use it daily. It is vented outdoors through a dryer hose. I used solvent paints the first 15 years with no explosions, no fires, no anything. The last 10 years I've been using acrylic paints exclusively and still no issues.

I read somewhere years ago, that if you can't smell the (solvent) paint while standing 6 inches from the booth, then you have adequate airflow. The bathroom fan fulfills this requirement.

Jay 

C-415 Build: https://imageshack.com/a/tShC/1 

Other builds: https://imageshack.com/my/albums 

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Posted by doctorwayne on Tuesday, January 11, 2011 8:24 PM

Railphotog

One advantage of a high CFM fan in a spray booth is that it is very effective in drawing dust into the booth onto your freshly painted model.

LaughLaugh

 

I built my spray booth using 3/4" plywood as the base, with sides of 1/8" Masonite pop-riveted together with lengths of leftover wall moulding from a suspended ceiling.  The fan, from a discarded air hockey table, is in the metal furnace fitting and directly in the air flow, with one half of a standard 11"x22" furnace filter below that in a home-made holder attached to the inside top of the booth.

 

As you can see in the photo, I included a turntable, but I found it an unnecessary feature and don't use it.

The flexible plastic ductwork, in service for over 25 years, was replaced with metal duct when I moved my paint room to the garage last year. The advantage of having it in the garage (it's about 100' behind the house) is no noise to disturb anyone - I often paint late at night, when everyone else is sleeping.  The other advantage is having a make-up air supply.  While the booth was vented to the outdoors when it was in the basement, the tightness of the house meant that the fan struggled for lack of air to make-up that which it was expelling.  In the garage booth (only 4'x8'), I included a closeable vent (keeps the mice and bugs out when not in use) to allow a constant supply of air to replace what the fan sends out the duct.  While I haven't measured the cfm, I'd estimate it to be double what was available with no make-up air.  By the time I've cleaned the airbrush (a minute or two), there's no odour of paint solvents left in the room.

As others have mentioned, always wear a two-stage respirator when spraying, booth or not, and regardless of the type of paint you're using.  Also, change the filter in the spray booth as required, to ensure full airflow.

 

Wayne

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Posted by Steve_F on Tuesday, January 11, 2011 9:56 PM

I use a respirator in my garage which I don’t remove until I have ventilated the room. I would love to have some sort of extraction system which I might add is something I am planning on but even so I would and will still wear a respirator until the fumes have dissipated.

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Posted by Javelina on Wednesday, January 12, 2011 6:59 AM

I can't stand this. I've got to weigh in on the old "You'll blow yer house to smithereens" claims by the Grainger guy and others. Most range hoods, fart fans etc. use a muti-pole AC motor with different windings to control the speed. The motors don't have brushes, hence no sparking, hence no ignition source, hence no BOOM! Now, if you use a motor from the old shop vac the kid backed over or some other motor with brushes, well there's yer problem. You can double up on the safety if you want by using a fan with plastic blades, especially if your housing is metal. If the fan housing is home made from wood, metal blades won't cause a spark. Put the power switch in an "outdoor" type sealed utility box so it's sparking can't cause probelms, make sure the blade can't spark (as above) and using a motor with no brushes will make a safe booth. For It's and Giggles, run a grounded cord and use a ground wire with an alligator clip to a plumbing pipe so static discharge won't getcha.

Lou

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Posted by maxman on Wednesday, January 12, 2011 9:54 AM

Javelina

I can't stand this. I've got to weigh in on the old "You'll blow yer house to smithereens" claims by the Grainger guy and others. Most range hoods, fart fans etc. use a muti-pole AC motor with different windings to control the speed. The motors don't have brushes, hence no sparking, hence no ignition source, hence no BOOM!

No, I can't stand it either.  Did anyone bother to go look at the link I posted? http://modelpaint.tripod.com/booth2.htm

I didn't think so.  In that article the author talks about the different types of blowers.  He says that you won't find a motor in a production type spray booth unless it is explosion proof.  Obviously not necessarily the case for us.  But he goes on to discuss the motors in kitchen and bathroom fans and has a concern about the susceptibility of the windings to paint solvents.  Basically he says that if you use these to be careful.  Maybe they make these motors differently now.

And concerning the "high airflow sucks in dust" arguement, he shows three different types of booth design: cross draft, updraft, and downdraft.  Each has a different airflow requirement suggestion.  He goes on to say that if you have concerns about the fan sucking dust into the booth, then you really have a cleanliness problem in the room where you're working.

In my personal experience with home made booths, when I originally made mine from the MR article I chose to use one of those plastic (if that's what it was) dryer vent hoses with the flexible spring inside.  I thought I didn't have to use the metal duct that was recommended.  Everything works, right?  Well, that vent deteriorated and allowed fumes into the room.  I replaced it with a metal variety.

Now everyone can do whatever works for them and whatever personally makes them comfortable.  But it is my opinion that when someone asks a question of this nature we should direct them to the best advice available, unless we have some technical background that superceeds the available information.  Something like "this is the better way to do it, but this method works for me"  would, I think, be acceptable.  Not "don't listen to him because he's full of vapor and what I do hasn't killed me (yet)".

Anyway, that's the end of my particular rant.  I will now take my 60 plus year old body outside and do some heavy lifting driveway shoveling, since that hasn't given me a heart attack (yet). 

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Posted by jrbernier on Wednesday, January 12, 2011 10:15 AM

  My first spray booth used a 30" range hood.  The range hood had a 3 position switch - the 'HI' was so strong, it sucked the paint  up and nothing got on the model!  I always used the 'LOW' setting after that.  I tend to get into 'overkill' on projects and build 'big' things(like a 30x30x12 spray booth).  The new spray booth will be about 16x16x12 inches.

  That said, I need to take my 60+ body outside to remove some snow myself!

Jim

Modeling BNSF  and Milwaukee Road in SW Wisconsin

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Posted by Michael6792 on Wednesday, January 12, 2011 12:58 PM

Javelina

I can't stand this. I've got to weigh in on the old "You'll blow yer house to smithereens" claims by the Grainger guy and others. Most range hoods, fart fans etc. use a muti-pole AC motor with different windings to control the speed. The motors don't have brushes, hence no sparking, hence no ignition source, hence no BOOM! Now, if you use a motor from the old shop vac the kid backed over or some other motor with brushes, well there's yer problem. You can double up on the safety if you want by using a fan with plastic blades, especially if your housing is metal. If the fan housing is home made from wood, metal blades won't cause a spark. Put the power switch in an "outdoor" type sealed utility box so it's sparking can't cause probelms, make sure the blade can't spark (as above) and using a motor with no brushes will make a safe booth. For It's and Giggles, run a grounded cord and use a ground wire with an alligator clip to a plumbing pipe so static discharge won't getcha.

Lou

 

I have to agree about not blowing your house up, most motors these days are brushless. The comment about the shop vac motor did remind me of something that happened not far from here about a year ago.

 

A gentleman was trying to siphon the gas out of his boat tank (not sure why) and decided to use a shop vac ( again, not sure why) Long story short, he had 3rd degree burns over 50% of his body & burned his garage to the ground (which contained his boat, 2 snowmobiles, quad runner, truck, freshly restored camaro among other yard implements.

Michael

Never attempt anything you don't want to explain to the EMT

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Posted by mokenarr on Wednesday, January 12, 2011 2:51 PM

Like the fellow above I built mine from plywood  , used a brushless fan and a filter.  One thing I did that works well is for the top of the paint booth I used a clear piece of plastic which allows me to place a light or 2 above the paint booth for excellent light.

Old Steam loco's never die, they just lose thier fire.
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Posted by steemtrayn on Wednesday, January 12, 2011 3:26 PM

I would never buy a spay booth for home use. Better off taking the cats to the vet.

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Posted by selector on Wednesday, January 12, 2011 4:33 PM

Laugh

Last time I attempted to spay at home, I was the one left neutered.

Never mind...it's a long and sordid tale.   I still sing bass in the local choir.   Another story.

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Posted by doggonenet on Thursday, January 13, 2011 8:31 AM

I hope I’m not a nuisance to modelmaker51, but I’m new to all of this discussion board stuff.  I’ve sent the same question on various sites, but not sure if I did it correctly.  So here goes again from yet another web location.

Modelmaker51 indicates that he used petroleum based paint for years, but now uses acrylic paint almost exclusively.  I’d like to know why the switch?  I’m asking this question because I purchased a book from Scale Auto Magizne about airbrushing.  The author used petroleum based paints for all painting.  He thinned the paints 50:50.

Is one type of paint better for airbrushing than another?  Do you need to thin acrylic paints 50:50?

If not 50:50 is there another ratio for thinning?

 

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Posted by doctorwayne on Thursday, January 13, 2011 12:07 PM

I certainly can't speak for MM51, but I've used lacquer-based paints almost exclusively for over 40 years.  Each paint manufacturer has recommended thinning ratios for their own paints, and it often includes recommendations that the painter use the manufacturer's own brand of thinner, too.  Experience shows that suitable alternatives exist for both the thinning ratios and most thinners.

While I had used water-based paints in the past, I found them to be more suitable, for the most part, for brush painting rather than airbrushing.  However, many paint manufacturers have begun making better water-based paints and several years ago, I decided to try them again.

Since Floquil lacquer-based paints have long been my favourite, I tried their PollyScale line of acrylic paints.  Initially, after reading several on-line discussions about using these paints, I used the thinner (alcohol) and spray pressures  (higher than the 20-25psi which I use for Floquil) that most seem to favour  to get the best results. 

My experiences were less than promising, and I spent more time unclogging the airbrush than I did painting.  I was on the verge of tossing that paint in the garbage (its nice brush-ability saved it Smile, Wink & Grin) but turned to PollyScale's (now part of Testors) website for additional information.

Surprisingly, their recommendations for thinner were their own brand or distilled water, and spray pressures of 15-20psi.  Even more surprisingly, they worked! Whistling  Now, in addition to Floquil and other lacquer-based paints, PollyScale has a prominent place in my paint cupboard.  I still prefer the solvent paints for their ease of clean-up, but acrylics can do any painting tasks as well or better.

For general painting with Floquil, I find a ratio of 50% or less thinner gives good results, and this seems to be similar for most other brands which I've used.  For weathering with Floquil, I like to use 90% thinner when airbrushing.

I use distilled water with PollyScale, and find similar ratios work well, including up to 90% for weathering.  

Some colours or some applications benefit from different ratios, but this is usually learned through experience - don't be afraid to experiment after first trying what's recommended by the manufacturer.

Part of the reason that some long-time painters have switched to acrylics is the pressure being brought on manufacturers to switch to more "eco-friendly" options - a noble pursuit, as long as the newer products perform as well (or better) than those which they replace.  In my experience, they do very well on most counts.  As I mentioned, I find clean-up more arduous, though, and the shelf-life of the thinned paints seems more limited than with thinned Floquil.

When airbrushing, regardless of which paint which you use, a well-vented spray booth is a good idea, and, spray booth or not, wear breathing protection:  I recommend a good-quality two-stage respirator, which will protect against all solvents and particulate matter.

 

Wayne

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Posted by TomDiehl on Saturday, January 15, 2011 1:07 PM

Javelina

I can't stand this. I've got to weigh in on the old "You'll blow yer house to smithereens" claims by the Grainger guy and others. Most range hoods, fart fans etc. use a muti-pole AC motor with different windings to control the speed. The motors don't have brushes, hence no sparking, hence no ignition source, hence no BOOM! Now, if you use a motor from the old shop vac the kid backed over or some other motor with brushes, well there's yer problem. You can double up on the safety if you want by using a fan with plastic blades, especially if your housing is metal. If the fan housing is home made from wood, metal blades won't cause a spark. Put the power switch in an "outdoor" type sealed utility box so it's sparking can't cause probelms, make sure the blade can't spark (as above) and using a motor with no brushes will make a safe booth. For It's and Giggles, run a grounded cord and use a ground wire with an alligator clip to a plumbing pipe so static discharge won't getcha.

Lou

Another thing to consider is that the guy at Grainger is looking to sell you a spray booth (didn't know they sold spay booths). Even though they sell vent fans, their profit level is lower, so the opinion they'll offer is not free of bias.

Others have made the point of wearing the proper respiratory protection, remembering the old rule, if you can smell it, you're inhaling it. I'd like to add if you use any type hose for the venting to the outdoors, inspect it regularly. Any buildup on the inside, or cracking or brittle spots on the hose are indications it needs to be replaced. These type hoses are not expensive.

Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by dcb_13 on Tuesday, February 13, 2018 1:11 AM

Hey, Jim. I was wondering if you could show some pictures of your spray box. I'm building my own, and would appreciate some guidance. Thank you very much.

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Posted by Overmod on Tuesday, February 13, 2018 11:48 AM

Be sure your 'inside' spray box can deal with what may be surprising momentary levels of house dust (you're better off not knowing some of what's in it).  If you use a furnace filter, spend the extra simoleons for the full 'allergen capturing' particle filtration; I backed mine up with one of those 'passive' electrostatic prefilters that work off air movement to develop the differential static charge.  If you have smaller intakes, make them so they take, and seal across, one or more HEPA vacuum filters.  I suspect a year's worth of actual spraybooth running time will not load these too highly, but even the tiniest dust particles should be caught.

This also implies you seal or gasket any 'suction-side' gaps.  Tape that quacks is probably sufficient in most places.

Depending on where you live, you might want a postfilter to catch overspray and such from the painting before it gets to the fan.

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Posted by BigDaddy on Tuesday, February 13, 2018 7:05 PM

dcb_13
Hey, Jim. I was wondering if you could show some pictures of your spray box.

Jim is still around, unlike most posters in the usual 7 year old thread.  Haven't seen this thead before but there have been lots of spray booth threads in the last 3 years.

 

Henry

COB Potomac & Northern

By the Chesapeake Bay

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Posted by ricktrains4824 on Tuesday, February 13, 2018 9:39 PM

Myself, I only spray acrylics, for a few reasons.

First and foremost, I have asthma. No solvents equals less smell. (Old house, no where near air tight as newer construction, so even venting the booth outside, some smell ends up back inside...)

Other reasons, is cost. For weathering needs, I can get a $1 bottle of craft store acrylic, and thin it enough to spray, and end up with about 4 times the paint, for 1/4 or less of the price of "hobby" style paints. (Even using Acrylic Airbrush medium to thin it with!) 

And, Acrylic's work just as good as enamel, and other solvent based paint, so long as you use it correctly.

Ricky W.

HO scale Proto-freelancer.

My Railroad rules:

1: It's my railroad, my rules.

2: It's for having fun and enjoyment.

3: Any objections, consult above rules.

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