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[Finished] Homemade spray booth project, an attempt.


Housesparrow
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Notice: Go here to see a later post in this thread to see the final result: http://www.britmodeller.com/forums/index.php?/topic/234991809-finished-homemade-spray-booth-project-an-attempt/?p=2186396

I will have to do some detective work, but I thought I'd start by making this thread.

I acquired this nice transparent storage case shown in the image below, and I have 6x used Noctua NF-P12 fans that fit nicely at the bottom of the case.

maxg8m.jpg

I think I can make this work, but there is one problem that I am not sure how to deal with:

Q: How do I power the six 12V (1watt) fans from the 230V power outlet?

Presumably this is easy, but I have really no idea. Hopefully someone knowledgeable can chime in and state the obvious solution. That would be much appreciated. :)

Putting on a hose and finishing the rear part behind the fans seems easy, so the power conversion problem is what seem difficult for me at this point.

Ah, I forgot to point out the specifications for the NF-P12 fans:

DC 12V (unsure if the 'direct current' part is important)

Size: 120 x 120 x 25mm

Rotational speed = approx 1300 rpm

Airflow = 92,3 m3/h = 1,54m3/min = 54 cfm

Static pressure = 1,68mm H2O

Acoustic noise = ca 20 dB

Input power = 1,08 W

Input current = 0,09 A

1,54 x 6 = 9,24 m3/min = 324 cfm (unsure if it makes good sense multiplying these numbers by six)

9,24 seem to be double of what a popular spray booth seem to push out, though I am not certain the numbers for these two solutions are directly comparable. *unsure*

Edit: Hm, I wonder if the six fans would be powerful enough. The popular spray booth on Amazon uses supposedly a 25W fan, which seem more powerful than my 6,5W setup. Not sure what to think about this.

I have a 15cm wide table fan that uses 20W, that one doesn't really feel that powerful to me.

Hm, I vaguely recall my compressor having 17L/min airflow, roughly 40-50psi constant pressure, unless I am totally mistaken. Maybe around 9L/min with 25 psi? Just guessing though.

Edited by Housesparrow
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Aha, I see somewhere in some forum, that someone that made a similiar thing to mine used a PC power supply. I have one lying around. :D

Hm, but the power supply I have is fairly heavy. I should be able to use it for testing the fans though, and then I can try find some smaller converter/power supply somewhere.

I guess I should buy a power on/off switch. Have to figure out how to best create the rear part that is intermediate between the fan exhaust and the hose leading to the windows. I guess I could use a plastic bag cut into pieces, and maybe stiffened somehow with cartboard.

I also have to figure out how to create a filter.

The transparent box I have, had a lid on it, so that can be put on to close my future airbrush spray booth. If I can get it all to work ofc.

Edited by Housesparrow
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Does anyone know if some kind of potentiometer is required between the 12v/1W fans and the powersupply? :)

My initial thought, not being an electrician, is that when connected to 12V power, the fans simply pull 1W of power each. I am not 100% sure this is how it works though.

I remember that the Noctua fans came with several noise dampening things, that added resistance to the wires and lowered the voltage.

Edit:

The wires on the fans are colored the following. Presumably only two of them is required to power the fan, with the third one being used optionally for measuring the fan speed iirc.

1 Black

2 Red'ish

3 Yellow green'ish

At present time, I am guessing that black = negative and red = positive.

Edited by Housesparrow
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I seem to have solved my first big problem. I found a very cheap (approx. £12) 230V to 12V converter, with an on/off switch.

This product is rated for "max 15W". Someone suggested that I avoided the ones that were explicitly in the 10-50W range, fearing that the low 6'ish watts pulled from my six fans would cause an issue with the transformer (also they were more expensive).

Product name seem to be "North Light", used for powering LED strips (2W each).

I think' ill use my six fans (= 6+watts) and then add two LED light strips (= +4W), for a total of 10watts (warm white).

I have one fan working with this, presumably, the LED light strips will light up if I connect it. Have to test that somehow.

1y7qdu.jpg

Not sure how to connect it all. Presumably I could just tumble the 6+2 wires into positive and negative slot on the sugar bit, and voila, I imagine that would work. I use this enclosed sugar bit, so it is a little safer to use.

Next up, the things behind the fans. At table height, a 125mm Ø hose would reach over to a window horizontally, about 100cm off. Presumably, I could use this silvery "metallic" hose thing I saw, that can twist and expand outwards (3m max), and then clinch the exhaust hole to fit the window opening with the window nearly closed. I only hope the six fans is powerful enough to at least push the air out that distance.

Next big problem is creating a funnel around the six fans and have it taper to the 125mm Ø "metallic" hose intake, and make it stiff enough, and allowing air to actually be pushed into the hose.

Hm, I think I ought to glue on a tunnel of sorts onto each of the fans to help steer the air forwards, or even, help stear the air towards a center.

Edit: I have probably been over thinking it. Building a custom shape behind the fans seem like a hassle. Now, I imagine that a box on top of a box could work, though there has to be a perfect seal between the two. I don't doubt the six fans will suck up the spray from the airbrush, however I am not 100% convinced that the six fans can push the air out the ca 100cm long air duct up towards the window. :P

On the top of the boxes in the image below, there is a white mouth piece for the eh hose to be fitted. I have to cut away the first ring. The whole thing is stepped, so I placed 1cm wide stripes of masking tape all around inside, to cover the step inside, so that there is less resistance to the air. Hopefully the Tamiya masking tape won't simply dry out and fall off with time. Cutting into that plastic is a little difficult. Using a regular saw, but only with repeated backwards movements, so it takes a little time, I am halfway cutting off the smallest ring there.

f3x56e.jpg

Edit: Nice. In ithe image below, you can see I have connected the two wires from the 2W LED light strip into the sugar bit, together with the two wires from the fan (one wire for fan speed is left unused), and it all works. :) Now I must try to see if I can jam all the wires into that one sugar bit to power six fans and two LED lights. Not sure the light from the LEDs will look great, because the light is so strong it creates shadows, where none was before. The wires from the LED strip weren't colored, but I suspect that it doesn't really matter here. I put the striped wire with the black one, and the white wire with the red one from the fan.

b66g4n.jpg

Fyi, the LEDs doesn't really look like in the image above. The camera turned the light into a glow. Instead there are multiple bright lights in a row.

Hm I think I'll try putting on some baking paper around the LEDs (or whatever it is called in English), to soften the light. The two lights is to go on the outside of the box, so they don't collect paint from the airbrush.

Or, maybe I could simply airbrush the protective piece of transparent plastic with Vallejo white. Btw, I noticed that even though this LED is labeled "warm white", the tiny LEDs are not of the same color. It looks like there is a mix of repeating white-white-yellowish-white-white-yellowish-white-white etc.

Edited by Housesparrow
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I might as well add another left-over Noctua 120mm fan I have. :) Now going for a seven fan setup.

The Noctua 'NF-F12 PWM' fan has a directional airflow, so I'll add that one just before the intake to the hose going to the window. Hopefully that seventh fan will get the airflow moving in the 100cm hose. The hose diameter is 125mm, I hope that isn't too wide.

I had been wondering if having a single fan at the entrance of the hose would obstruct the airflow pushed out from the six fans, but since this one is also a 120mm one, there is some spacing around it, for air to pass it. *shrugs*

The one LED strip I bought previously, was airbrushed with Vallejo White primer, and then I brushed on a light gloss coat with Humbrol Clear to protect the paint.

I just connected the 4 wire PWM fan to my 230-12 V converter and apparently the fan is working nicely.

Fan wire color vs converter wire color

Black --> Blue (+?)

Yellow --> Red (-?)

Green (unused)

Blue (unused)

Fan stats (lol, not exactly a blow dryer)

DC 12V

Size: 120 x 120 x 25mm

Rotational speed = approx 1500 rpm

Airflow = 93,4 m3/h = ca 1,54m3/min = ca 54 cfm

Static pressure = 2,61mm H2O

Acoustic noise = ca 22,4 dB

Input power = 0,6W

Input current = 0,05 A

I had a 140mm fan lying around, but I thought the focused airflow of this 120mm fan would be more suitable. I had all of these 120mm Noctua fans unused, becaused I switched to using all 140mm fans in my desktop computer case some time ago.

I ordered a Fujifilm FinePix JZ700 digital compact camera, and will go buy some el cheapo tripod for more perfect still photos. :) Should get the camera tomorrow. Unfortunately, I ran out of money, so I can't possibly finish this spray booth project until another week has passed.

http://www.fujifilm.com/products/digital_cameras/j/finepix_jz700/specifications/(2013 model)

I did get to buy most of the bolts and screws and whatnot, and 10m of sticky tape. Will have to buy one more LED strip (2W) and the 70-300cm metallic hose. Hm, the hose will probably be back heavy, so I must make sure the exhaust port doesn't come loose and fall down, or risk having the entire spray booth falling backwards and down with it.

I think this custom spray booth will work nicely, or it could turn out to be a total failure performance wise. :D Unsure if I can be bothered to switch the fans to something more powerful it this setup doesn't work.

Place your bets!

Edited by Housesparrow
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You're doing some good work here, but you really need to make sure that the fans are designed to be safe in an explosive atmosphere. If they produce even the smallest sparks when in operation, then they could ignite a cloud of aerosol vapour/particles and cause a lot of damage.

I'd also worry about static build-up on that plastic crate, as that presents another ignition hazard.

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Apparently these fans use proprietary SSO bearings. A schematic show the moving fan part rotating around an axis, encased in oil, all driven by a magnet that is fixed to the fan frame. Doesn't look like there will ever be a spark there, but I'm no expert. :D

http://www.noctua.at/main.php?show=sso_bearing&lng=en

I understand your concern. I just don't quite know what to make of it, with regard to for example a build up of static electricity. :|

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You're doing some good work here, but you really need to make sure that the fans are designed to be safe in an explosive atmosphere. If they produce even the smallest sparks when in operation, then they could ignite a cloud of aerosol vapour/particles and cause a lot of damage.

I'd also worry about static build-up on that plastic crate, as that presents another ignition hazard.

The idea of fans creating sparks to ignite a paint/air mixture is without substance IMHO.

I've been using fans for years without any problem & my spraying is with flammable enamel / cellulose, not acrylics.

A few years ago I conducted a test, using a remote gas cooker ignition sparker & a plastic box filled with vapour from cellulose thinner.

Repeated attempts failed to ignite the mixture.

Filling the box with flour dust produced a rather loud bang however!

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A few years ago I conducted a test, using a remote gas cooker ignition sparker & a plastic box filled with vapour from cellulose thinner.

Repeated attempts failed to ignite the mixture.

Sound like you were trying to win a Darwin award ...

But it's nice to know that nothing happened as I have a similar home made setup. Been using it for 10+ years and I'm still here, but some might say that's more down to luck than anything else ... ;)

Edited by Foghorn Leghorn
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I seem to have solved my first big problem. I found a very cheap (approx. £12) 230V to 12V converter, with an on/off switch.

This product is rated for "max 15W". Someone suggested that I avoided the ones that were explicitly in the 10-50W range, fearing that the low 6'ish watts pulled from my six fans would cause an issue with the transformer (also they were more expensive).

Product name seem to be "North Light", used for powering LED strips (2W each).

I think' ill use my six fans (= 6+watts) and then add two LED light strips (= +4W), for a total of 10watts (warm white).

I have one fan working with this, presumably, the LED light strips will light up if I connect it. Have to test that somehow.

1y7qdu.jpg

Not sure how to connect it all. Presumably I could just tumble the 6+2 wires into positive and negative slot on the sugar bit, and voila, I imagine that would work. I use this enclosed sugar bit, so it is a little safer to use.

Next up, the things behind the fans. At table height, a 125mm Ø hose would reach over to a window horizontally, about 100cm off. Presumably, I could use this silvery "metallic" hose thing I saw, that can twist and expand outwards (3m max), and then clinch the exhaust hole to fit the window opening with the window nearly closed. I only hope the six fans is powerful enough to at least push the air out that distance.

Next big problem is creating a funnel around the six fans and have it taper to the 125mm Ø "metallic" hose intake, and make it stiff enough, and allowing air to actually be pushed into the hose.

Hm, I think I ought to glue on a tunnel of sorts onto each of the fans to help steer the air forwards, or even, help stear the air towards a center.

Edit: I have probably been over thinking it. Building a custom shape behind the fans seem like a hassle. Now, I imagine that a box on top of a box could work, though there has to be a perfect seal between the two. I don't doubt the six fans will suck up the spray from the airbrush, however I am not 100% convinced that the six fans can push the air out the ca 100cm long air duct up towards the window. :P

On the top of the boxes in the image below, there is a white mouth piece for the eh hose to be fitted. I have to cut away the first ring. The whole thing is stepped, so I placed 1cm wide stripes of masking tape all around inside, to cover the step inside, so that there is less resistance to the air. Hopefully the Tamiya masking tape won't simply dry out and fall off with time. Cutting into that plastic is a little difficult. Using a regular saw, but only with repeated backwards movements, so it takes a little time, I am halfway cutting off the smallest ring there.

f3x56e.jpg

Edit: Nice. In ithe image below, you can see I have connected the two wires from the 2W LED light strip into the sugar bit, together with the two wires from the fan (one wire for fan speed is left unused), and it all works. :) Now I must try to see if I can jam all the wires into that one sugar bit to power six fans and two LED lights. Not sure the light from the LEDs will look great, because the light is so strong it creates shadows, where none was before. The wires from the LED strip weren't colored, but I suspect that it doesn't really matter here. I put the striped wire with the black one, and the white wire with the red one from the fan.

b66g4n.jpg

Fyi, the LEDs doesn't really look like in the image above. The camera turned the light into a glow. Instead there are multiple bright lights in a row.

Hm I think I'll try putting on some baking paper around the LEDs (or whatever it is called in English), to soften the light. The two lights is to go on the outside of the box, so they don't collect paint from the airbrush.

Or, maybe I could simply airbrush the protective piece of transparent plastic with Vallejo white. Btw, I noticed that even though this LED is labeled "warm white", the tiny LEDs are not of the same color. It looks like there is a mix of repeating white-white-yellowish-white-white-yellowish-white-white etc.

You could mount the leds on the edge off the box and cover the outside and the leds and say around an inch on the inside with brown paper, that way the light should travel through the box walls!

Edited by Suggy
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I admire your inginuity and industrious flair but you only need one spark and one bang. I would listen to Paul from Little cars. I took the hit and bought an extraction unit and sit with no concerns when spraying, the one time I forgot to switch it on there was a haze in the room which made me realise just how much is expelled in volume by these units.

Your choice though, just offering alternative opinions.

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I do not have the time or ability to do this I am afraid. I bought one of the foldable booth's that come with the LED lights. The most work I had to do was drill a hole in my shed wall for it to vent. £50 inc. postage.

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I do not have the time or ability to do this I am afraid. I bought one of the foldable booth's that come with the LED lights. The most work I had to do was drill a hole in my shed wall for it to vent. £50 inc. postage.

Have to agree, think you are over thinking the whole thing is over elaborate tbh. Unless it it has become a 1:1 scratch build of course, in which case, enjoy! :thumbsup:

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Sigh, this is either going to take a long time if I try cut out the holes little by little, or get really loud if I use my dremel to cut out the holes in the ABS plastic. :(

The ABS plastic was surprisingly fragile, and apparently the plastic can end up with a crack stretching out from the point of pressure if you are not careful.

Hrm, i'll use the dremel I think, though I should wait until monday. Using the dremel is so very noisy. :D

2czajpc.jpg

Edit: Using a dremel was quick enough.

I'll go buy an inexpensive power tool to screw in all the 24+ screws, because screwing all of the screws with this tight fit, by hand, is too much work imo.

If I am lucky, I can perhaps use the hollow space in this box, to store the hose/airduct, assuming it will easily bend and if it will fit inside this box. And then I close it up with the original lid for the box.

2h7feyo.jpg

In the image below: The 7th 120mm fan (this one being directional) goes here, not big enough for the hole, but perhaps that is good, because I don't think that one fan can push the same amount of air that the other six does, and I don't want a relatively weak fan to slow things down at the entrance to the airduct/hose.

2zr2pgl.jpg

Edited by Housesparrow
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I've just been prompted to clean my old cooker hood spray booth for about the fourth time, and on removing the lid the place was FULL of paint dust, so much so that you couldn't even see the coils on the motor! I must have removed over 2 cup-fulls from the motor housing, fan cylinder and the air exit, and now my booth is behaving nicely, and sucking like a... well, you make up your own smutty saying ;)

Just goes to show that cooker hoods are pretty resilient things, and although mine now squeaks a little on startup (probably worn bearings), it still works after eight years, and I haven't yet exploded or any other horrible fates that the scaremongers would have you believe happen. Afterall, what idiot would design a cooker hood that could end up sitting over a gas hob that could be left unlit, without properly shielding the motor? :shrug:

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haha probably a Chinese one, and before anyone says don't knock them I work in white goods so have first hand experience on their build quality but I have to say not a cooker hood as yet

As Mike points out there would have to a one hell of a build up, more likely that the motor would burn out from lack of cooling than explode

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Does anyone know if some kind of potentiometer is required between the 12v/1W fans and the powersupply? :)

My initial thought, not being an electrician, is that when connected to 12V power, the fans simply pull 1W of power each. I am not 100% sure this is how it works though.

I remember that the Noctua fans came with several noise dampening things, that added resistance to the wires and lowered the voltage.

Edit:

The wires on the fans are colored the following. Presumably only two of them is required to power the fan, with the third one being used optionally for measuring the fan speed iirc.

1 Black

2 Red'ish

3 Yellow green'ish

At present time, I am guessing that black = negative and red = positive.

correct just wire them up in paralel and they just draw 1 watt each (which at 12v is approx 0.08 amps each ie all 4 will only pull less than 0.5a) if you get a 1a 12v psu thatl be more than enough

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  • 2 weeks later...

Meh, I bought this cheap wire stripper, but it was useless, poor quality, and didn't really work at all for my 1.5mm wires. Useless thing.

I am optimistic that the six fans will work nicely for sucking out enough air, though I can only hope that the fans are equally effective with a filter in the way.

I would have been more accurate if it weren't for the bottom of the basket being non planar, bulging slightly inwards.

Trick question: How many fans to you see in the picture? :)

29o37yx.jpg

So, this image below is a better image of how the whole thing will basically look like. The 7th fan is missing here atm.

2cnwk8h.jpg

The plan is to make four holes, and put in four screws to connect the two transparent baskets, and then use wide sticky tape to seal the connection. The screws will make sure the two baskets don't fall or sag away from each other.

I bought this el cheapo electrical drill 3.6V for screwing all the screws, amazing thing (ca £14). 3-5 hours recharging time. Speaking of screws, I think all the nuts were redundant, the fans wouldn't go loose ever even without the nuts.

Ah, I nearly forgot: When I used the dremel today to cut out openings for the fans, I was careless and the cutting disc touched one of the tiny wires that was very close to the fan blade. I had to go buy some stuff to splice the wire. Scary.

Using the dremel and the electrical drill was so noisy, I had to take a break, being worried the neighbors would start complaining. I hope to finish building this thing tomorrow. There are 18 wires to be stripped, I hope that goes well, or I will get a little annoyed. :D

I bought a cheap glue gun (melts plastic). Thought I could use it for fastening the sugar bit used between the main power wire and all the other smaller wires, and maybe for gluing clasps to the plastic on the inside for fastening the filter fabric I have.

Edited by Housesparrow
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Heh, I expected this to look better, but it will have to do. :) Because of my worry about the fans perhaps not being able to perform adequately, I did not want to put too much effort into building this spray booth. Good thing I had these Noctua 120mm fans lying around, otherwise it would have been expensive to buy them all again. :D

7th fan (directional fan) is now in place. The 7th fan is somewhat smaller than the exhaust intake and so that fan doesn't cover the entire passage.

64i820.jpg

Edited by Housesparrow
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I'd like to see it in action now to see whether the fans pull the stuff through the boxes quickly enough. I'd have thought that the six fans might overpower the one in the ante-chamber, but I'm no expert :shrug: At least with it being transparent (initially at least), you'll be able to see where it's going. Have you got any source of smoke that you could run a visual test on? Might be less messy than paint :)

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I think Mike's right. If each fan can move x litres/minute, then after the first minute you'll have 6x litres in the plenum, from which the 7th fan will only be able to remove x litres.

This will build up a higher pressure in the plenum and that will tend to prevent any more extraction from the main chamber.

I really don't think this is going to work well on several levels I'm afraid.

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