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Paint Booth

The 10x10 would work great for a parts painting booth. I made a booth from the 10x20 size on Amazon and painted the whole plane in it before final assembly .
 
I've used a 10x10 folding beach canopy (no sidewalls) when painting a lot of things. Wings and fuselage, not so much. A 10x20 would feel tight painting wings and fuselage, but it would be workable, particularly if you made a couple of minor modifications to widen the sides to give yourself a skosh more working room. The obvious modification would be to slit the corners of the enclosure and guy out the walls a bit, leaving a gap at the bottom.

That would also help with ventilation - paint booths can get pretty foggy without good ventilation.
 
I'm looking at priming more than finish painting. I'm reluctant to setup a full time paint area in the hangar even though there is space for it; fumes and such with some small worry for carryover to other things...... But these canopies would be pretty easy to pop up in the grass behind the hangar for a paint day too. Two walls would block a fair amount of wind
 
I'm looking at priming more than finish painting. I'm reluctant to setup a full time paint area in the hangar even though there is space for it; fumes and such with some small worry for carryover to other things...... But these canopies would be pretty easy to pop up in the grass behind the hangar for a paint day too. Two walls would block a fair amount of wind

Please be careful about painting in a hangar as paint particles will find their way into adjacent structures. We had a guy who would paint in hangars at Long Beach and he trashed adjoining hangars with paint over-spray. Pi$$ed off a bunch of people. The complaints forced him to finish a job outside and he trashed some rental cars that were down-wind.

-Marc
 
Yep, exactly my concern; and my own other plane too.... Didn't know about the portable greenhouse - like it. Not as easy to setup and take down though.

I also have a large space in my hangar mezzanine where I could actually frame a room with no kidding door and lights; might actually be the cheapest way.
 
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For the over spray issue, you can buy an 18 foot x 24" diameter dog agility collapsible tunnel and direct the spray away with a fan. If you put a couple of bends in the tunnel the over spray will never even make it to the exit end and will just fall into the tunnel, all you get is the paint smell. It works really well, I painted my airplane in my paint booth and had lots of other stuff in the area (tractors, cars) and got zero over spray on anything else.
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Build your own

I framed in a booth using 2x2?s (about 4 ft x 8 ft). Wrapped the whole thing in heavy clear plastic tarp. I use 1 box fan mounted on the ceiling on hi blowing through a filter for inlet air and a second box fan mounted on down low on the far wall on a medium setting for exit air. The exit fan blows through two filters (I replace the 1st one periodically, but the 2nd has never gotten clogged). The fan settings create a bit of cross flow and a positive pressure in the booth. I paint right under the inlet so overspray is carried down and away from the part I?m painting.

Fumes do get into the rest of the hangar but I have never had an issue with overspray. When I first built the booth I did put a cardboard panel about 4 inches beyond the outer exit filter and checked it after painting for particles, but have never found any.

Whole thing including the 2 box fans and filters was under $150.
 
Generally speaking, if you keep any possible ignition source, like an unsealed fan motor, out of the exhaust stream, you lesson the risk of a combustible event. Professional booths typically use sealed explosion proof fans in the exhaust stream, typically behind a filter wall. Exhausting fumes is way easier than trying to design a system to force air through the inlet.
Explosions are rare, but they can and do happen. Each person rolling their own is making a decision to either accept, or ignore, that risk. While the risk may be low, even extremely low, it exists.

I either paint in ?free air? or in a properly designed booth, but that is just me.
 
One more consideration for paint booths...plastic does not hold dried paint very well. I've had several variations on paint booths over the time I've been building my 9A and now the 10 and I found that the dried over-spray would flake off the plastic walls during subsequent paint/prime sessions. The plastic also seems to generate a static charge that makes it want to brush up against me every time I'm near....hence more flakes.

You might consider buying some 9'x12' canvas drop cloths from your local hardware store instead of plastic.
 
I did a limited search and could not find a time where a home built paint booth exploded. There are some really weird accidents on the osha paint boot accident web site, but no explosions. Most of us have heard stories of how it can happen, but does anyone have first hand info?

I can verify if you do old style formica work in a basement with contact cement, make sure the water heater pilot light is off. Contact cement fumes are way different than paint fumes - especially with a HVLP gun.

I built a paint booth in my hangar with 2x2's and plastic. I had 2x2 filters on one side and 3 box fans on the other that vented out an open hangar door. I have a Hobby Air supply and I wore it, but I dont believe the air quality ever got anywhere close to being an explosion. Air exchange is the key.

On a side note, my gas ceiling heater ran the entire time and that may not have been the smartest thing.
 
Bildge blower

I built a temporary set up with a bildge blower as the exhaust. They are designed for exhausting fumes. They are 4" in diameter and dryer hose works great.
The frame is conduit hanging from the garage door frame. The sides are old shower curtains. Bildge blower is plumbed to a dryer vent installed in the shop wall. Set up is fast. It's only big enough for parts but it worked. Link is on my blog under Kitplanes Tips.
 
I don't see how a fan (for example a $20 20" Box 3-Speed Fan) can produce sparks, IF if is left on. In other words, put it on an extension cord and switch it on/off at an outlet that is not near fumes. Don't touch the switch on the fan while it's in fumes. These AC fans are brushless, right?

Finn
 
I don't see how a fan (for example a $20 20" Box 3-Speed Fan) can produce sparks, IF if is left on. In other words, put it on an extension cord and switch it on/off at an outlet that is not near fumes. Don't touch the switch on the fan while it's in fumes. These AC fans are brushless, right?

Finn

Take a motor's cover off, turn on the motor, turn off the lights and look at the brush area. constatnt tiny sparks between the brush and the armature. Easier to see on more powerfull motors. Brushless motors are expensive and not common on these size motors. DEFINATELY not common on box fans. Also, not sure that brushless is synonomous with sparkless. I beleive motors made for use in explosive areas achieve safety by enclosing/sealing the area with sparks, separating it from the surrounding air. Cooling is then the engineering challenge.

Larry
 
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I think it is reasonable (and safe) to assume any AC motor not rated as explosion proof is producing some spark. And it is definitely worth considering the risk before building a DIY paint booth. The reason I feel comfortable using mine is that due to the airflow through the booth, there is virtually no chance of fumes getting to a combustable concentration.

The typical 20? box fan has an un-restricted flow rate of 1000 to 2500 CFM. Mine are at the upper end of that, but assume 10% of that flow rate due to the restriction of the filters (250 CFM). The primary VOC in the paint and reducer I use is acetone. Worst case scenario for a wash primer is about 75% acetone.

The lower explosive limit (LEL) of acetone is 2.6% (by volume). That means I would have to be shooting about 1/2 oz of primer per second (sustained) to hit the LEL. I don?t get anywhere close to that flow rate of paint.

At that airflow rate though, my booth is nowhere close to laminar flow. It is positively ?breezy? in the booth, which is probably not as good for finish quality, but hey I?m just shooting primer anyway, mostly on surfaces I?ll never see.
 
Lots of engineers on here....
Lets say that I did want a 120V sealed motor blower. With a high CFM. cheap of course..... Anybody got any good ones in their bookmarks?
Ideally it would have an outlet to a 6" exhaust pipe outside.
 
EC motors are sealed.... found this:https://www.amazon.com/gp/product/B07JMHFJMR/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

Marketed to growers, not builders, eh?

I just bought the 8" version and it's pretty awesome, nicely built, very quiet, and two year replacement warranty.

However, it says right on the front of the instructions not to use in hazardous atmosphere, explosive gasses, significant dust, or near open flame. :eek:

Personally I'm not too worried for two reasons:
1) I don't think any brushless motor (EC, sealed, or otherwise) is capable of producing a spark, other than by static electricity on the housing or ducting, and
2) I don't think the concentrations will get anywhere near the explosive limit as stated by Jason

Watch for my obituary... :p
 
Personally I'm not too worried...

Ok, still not too worried, but after some asking and googling I do have more info on the matter.

Someone who works a lot with motors had the following to say:
"My thoughts on this: in terms of the electronic components, none of them should create sparks during their operation, but they still could, if they get damaged in some way. A brushless DC motor could still create a spark, when an electronic component has a fault. MOSFETs can literally explode. The windings could also create a spark, when the protection diodes were damaged. Other than electronic faults, a mechanical fault could have similar effects: Say the bearing wears out and steel rubs against steel! These are just ideas off the top of my head. I have not had to deal with ex-proof fans and I don't know how the difer in terms of their design."

Then after a quick search I found https://www.airsolutions.us/news/newsspark-resistant-fans-k-explosion-proof-fans/, which had this to say:
"Did you know that technically there is no such thing as an explosion proof fan? While there are enclosures and motors that are rated explosion proof, it is not possible to rate a fan as explosion proof. The reason: explosion proof design requires isolation from the potentially explosive air. By nature of the way a fan operates, a potentially explosive air stream will always be in contact with the interior of the fan housing and the fan impeller."

Apparently the appropriate fan standard is called spark-resistant, and makes no mention of brushed/brushless motor design. The standard, linked below, basically boils down to it's first footnote: "No bearings, drive components or electrical devices shall be placed in the air or gas stream unless they are constructed or enclosed in such a manner that failure of that component cannot ignite the surrounding gas stream."

So I guess people marketing explosion-proof/resistant fans are really selling spark-resistant fans with explosion-rated motors. A technicality perhaps, but interesting, at least to me. :)

http://www.reahvac.com/tools/amca-standard-99040186/
 
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