How to make a home-made spray booth

[AngryMeerkat]

Well as promised, I've made myself a spray booth today and here is a quick write-up of how I did it for anyone interested in doing it themselves.

 

Parts needed-

 

Shower/bathroom extractor fan kit - £24 from B&Q

A power lead - £4 from B&Q

Wood. MDF for bases, batten for base, plywood for sides and rear - off cuts from baseboard making

 

And that's it! Apart from the obvious screws and tools needed to work with wood. A circular saw, a mitre saw, a jigsaw, a drill for pilot holes and a drill/electric screwdriver. The extractor kit comes with everything needed including the extractor fan, grilles for the booth and exterior, and the plastic stretch tubing. I found the cheap basic extractor kit was best for this use, as the more expensive units require a pull chord to switch on and off and also run on a timer so not right for our use.

 

So first of all you need to decide how big you want your booth, and create a cut list for all the wood parts needed. As the turntable I've ordered is 10" across, I've made the rear of the booth 30cm across with it widening to 45cm at the front to create a wider opening to work in and also create a funnel forcing the overspray into the extractor unit. The sides are 30cm high, enough to contain overspray but still allow plenty of light into the booth.

 

 

 

Then it's a simple case of screw the parts together. To make things simpler it's best to mark and cut out the hole for the extractor grille before screwing the rear piece into place. It's worth noting that this extraction will move the air and paint around the booth, so some thought needs to go into this. If you mount the grill on one side or the other the fan will pull the paint to that side as soon as it comes out of the airbrush, not desirable while spraying! So it has to be rear mounted, but then we get to the height. Mount the grille too low and it will pull all the overspray and any dust in the air downwards, all over the item your painting! So it's best to mount the fan near the top of the rear to pull dust and overspray upwards and away from what you are painting.

 

 

Now you need to mount the extractor fan. To make extraction as efficient as possible it's best to keep the pipe between the grille and the fan as straight as possible, to do this I created a platform at the rear of the booth and using a couple of off cuts of batten I raised the fan to the height of the grille.

 

 

Once all this is done you have a working spray booth ideal for airbrushing or aerosol spraying. To improve how much light is present inside the booth I've painted the whole thing gloss white using exterior gloss paint, which should be hard wearing. Gloss white reflects more light than any other colour, and is cheap and can be quickly over painted when it gets dirty.

 

 

So there you have the finished spray booth! Total cost of £28 and some materials most of us will have laying around, much cheaper than the £70+/- that a professional booth will cost you. Granted it isn't as well finished, isn't collapsible and is probably a little heavier, but at less than half the price I can live with these things. The extractor fan is a sealed unit as it is designed to extract moisture from a shower enclosure, which means paint and thinners will pass through it safely without coming into contact with the electrics.

 

If you wanted you could of course go further with this and round off the front top corners, add an on/off switch (mine works straight from the plug), and add a filter to the grille. I may make these modifications over time if I deem them necessary, however at the moment I'm more than happy with what I've built with less than £30 and 4 hours of my time. It means I can throw the extractor hose out of the window in the man-cave and spray away without the Mrs complaining that the whole house stinks of paint.

 

Mark

[Andy Hayter]

I don't want to pee on your parade, but is the motor for the fan fully isolated from the extracted gas flow?

 

If not you run a risk of a fire or even explosion.  The extracted gas flow will contain flammable gas/droplets and if the motor contacts are sparking (not uncommon) and come in contact with the gas flow......................................

[ian@stenochs]

Hi,

 

Good stuff, I made one very similar a while ago and it works extremely well. If your fan has an induction motor there are no brushes to spark so safe on the thinners vapour.

 

I have used mine extensively and found that the fan blades collected a build up of paint which over time reduced the effectiveness of the 'suck' I had to dismantle the fan and chip off the build up but that restored it as good as new. To cut down on the cleaning I have added a coarse filter to catch the worst of the paint overspray. I use the fine fleece sold in B&Q to cover tender plants. They sell it by the metre off a roll. A piece about a foot square stapled onto a light wooden frame and mounted just in front of the fan lasts about a year before it is too clogged. Replacement takes but a few minutes.

 

Happy modelling,

 

Ian.

[PGC]

Looking at the B&Q site, the manufacturer of the unit is Manrose. I did a quick Google search - they're based in Slough so I 'phoned them up. All their fans are IP44 rated. When I asked if the motor in the B&Q unit would be an induction motor, the reply was "No, it's just an ordinary axial motor". Surely every motor of any kind is axial as it goes round, or am I missing something? Because of that, I decided to give up asking technical questions of the technical department! I then decided to use Google again to find out what an axial motor is, and I found this link. To my mind, this means an axial motor is brushless and therefore highly unlikely to spark. However, that's a guess - anyone want to shoot my theory down in flames? Please feel free to do so - I'm willing to learn!

 

After I'd been told about the IP44 rating I decided to try and find out what it means. From this link the first figure of the IP44 rating means that the fan is protected against most screws and wires of less than 1mm diameter. The second figure means that water splashing against the enclosure from any direction shall have no harmful effect on the fan.

 

I explained that there is some discussion on a modelling forum about the use of the extractor kit for a spray booth, and the immediate response was that they're not suitable, but surely that would be the natural response if the unit is being used for a purpose for which it wasn't designed. However, to my mind, the unit must be suitable, as I really wouldn't like the idea of having a motor to which water could get access - even though it's a long time since I did 'O' level physics, I do seem to recall that water and electricity aren't natural bed fellows! 

Phil

[PGC]

Hi,

 

Good stuff, I made one very similar a while ago and it works extremely well. If your fan has an induction motor there are no brushes to spark so safe on the thinners vapour.

 

I have used mine extensively and found that the fan blades collected a build up of paint which over time reduced the effectiveness of the 'suck' I had to dismantle the fan and chip off the build up but that restored it as good as new. To cut down on the cleaning I have added a coarse filter to catch the worst of the paint overspray. I use the fine fleece sold in B&Q to cover tender plants. They sell it by the metre off a roll. A piece about a foot square stapled onto a light wooden frame and mounted just in front of the fan lasts about a year before it is too clogged. Replacement takes but a few minutes.

 

Happy modelling,

 

Ian.

Ian

 

Out of interest, how long have you been using your unit, what paints do you spray through it and how often do you use it? I reckon that if you are using yours extensively as you say, you're spraying enamels through it and you still haven't blown your house up, it must be a relatively safe unit and counters the arguments of the naysayers who belittle these units.

 

Thanks

 

Phil

[ian@stenochs]

Ian

 

Out of interest, how long have you been using your unit, what paints do you spray through it and how often do you use it? I reckon that if you are using yours extensively as you say, you're spraying enamels through it and you still haven't blown your house up, it must be a relatively safe unit and counters the arguments of the naysayers who belittle these units.

 

Thanks

 

Phil

 

Hi

I build and paint about a dozen locos plus other items of stock per year. Almost all are 7 mm scale and I have been using my extractor for the last 10 + years. Celulose and enamel both from airbrusb and spray cans. House still here.

Happy modelling.

Ian

[JeffP]

Good idea.....the fan kit is £1.01 cheaper at Screwfix.

 

http://www.screwfix.com/p/manrose-in-line-white-20w-shower-fan-kit/15061#

[PGC]

Hi

I build and paint about a dozen locos plus other items of stock per year. Almost all are 7 mm scale and I have been using my extractor for the last 10 + years. Celulose and enamel both from airbrusb and spray cans. House still here.

Happy modelling.

Ian

 

Thanks Ian - that's another one in the eye for the H&S mob!!!!!!!!!

 

Phil

[PGC]

Good idea.....the fan kit is £1.01 cheaper at Screwfix.

 

http://www.screwfix.com/p/manrose-in-line-white-20w-shower-fan-kit/15061#

 

It seems the other way round, B&Q http://www.diy.com/nav/fix/plumbing-central-heating/ventilation-air-treatment/extractor_fans___kits/-specificproducttype-extractor_fan_kits/Manrose-100mm-Basic-Inline-ShowerFan-Kit-11478349?skuId=11989056 costs £24.98 and Screwfix £26.99. Also, the Screwfix unit say's it has a timer whereas the B&Q one doesn't.

 

Phil

[AndrewC]

I don't want to pee on your parade, but is the motor for the fan fully isolated from the extracted gas flow?

 

If not you run a risk of a fire or even explosion.  The extracted gas flow will contain flammable gas/droplets and if the motor contacts are sparking (not uncommon) and come in contact with the gas flow......................................

Sorry but this is a bit of an urban myth. If you were spraying pure lighter fluid (naphthalene) at a flame you still wouldn't get an explosion. It would burn but not explode.

 

A few things to know when spraying. Unless you are using canned air you are mixing the paint and thinner with plain air. In order to ignite the thinner has to be evaporated and of a significant ratio of vapour to air in order to ignite. On top of that the thinner is bound to the pigment at the time of spraying. This effectively means there is insufficient free flammable vapour being drawn through the fan to cause ignition. I've been using a similar home spun spray booth for a number of years and use naphthalene as a thinner for Phoenix and Humbrol paints. This is far more flammable than the usual thinners and I've had no issues. Of course if you are using propane or butane "air" cans to power your air brush then all bets are off as you are introducing far too much flammable vapour into the booth.

[AngryMeerkat]

I don't want to pee on your parade, but is the motor for the fan fully isolated from the extracted gas flow?

 

If not you run a risk of a fire or even explosion. The extracted gas flow will contain flammable gas/droplets and if the motor contacts are sparking (not uncommon) and come in contact with the gas flow......................................

And if I cross the road I 'run the risk' of being hit by a bus.

 

Unfortunately you've obviously read some hype somewhere, it's all been twisted, and suddenly this horrible myth is being thrown around as a warning.

 

I speak from experience as someone who has been a professional sprayer for 15 years, I've spent most of my working life around paint and it's application. From painting Ford Fiestas, to Ferrari F50s, to commissioning a spraying facility in an assembly plant in the Far East for a Major European motor manufacturer. This whole 'explosion' thing is a myth. Back in the bad old days I used to smoke in the booth while spraying, never blew anything up or set anything on fire. In fact, spraying directly from a spray gun onto a lit cigarette will do nothing but extinguish it. You see, one big fact that this myth misses is compression. In order for the small quantity of thinners that is mixed with the large quantity of moving air to ignite, it would have to be compressed. Nowhere during the spraying or extraction process does the air/thinners mixture become compressed, the booth is open and the extractor fan is constantly moving air from one opening to another, so compression cannot happen.

 

Please please please, for the sake of humanity, stop using urban myths as a Health & Safety fact. It's killing this country and it's production capability!

 

Mark

 

I will add one caveat to the above - while all of the above holds true for a small booth for airbrushing, a full sized industrial booth is quite different. Not in how things work, but due to an industrial booth being a sealed room in a state of vacuum and having anything up to 50 litres of paint per hour sprayed through them, the possibility of compression is there, due to the sheer volumes involved. However a booth for airbrushing will NEVER run at that capacity and isn't a sealed room in a vacuum so compression cannot occur!

 

Edited to add the above

 

Mark

Edited July 21, 2014 by AngryMeerkat

[BlackRat]

Had mine several years, well I have made more than one version, I reckon again about 10 years plus and no fires, explosions or underpants threatening moments at all! I

 

I even have the fan mounted direct to the box!

 

I use it now I preference to the ready to go portable model which I have never used!

 

Don't forget the cake icing turntable as well, £1.99 in Trago Mills :-)

[AngryMeerkat]

Had mine several years, well I have made more than one version, I reckon again about 10 years plus and no fires, explosions or underpants threatening moments at all! I

I even have the fan mounted direct to the box!

I use it now I preference to the ready to go portable model which I have never used!

Don't forget the cake icing turntable as well, £1.99 in Trago Mills :-)

I was in Trago Mills a few weeks ago during a holiday in Devon, gutted I didn't see these!! I've ordered one off eBay - £4 including delivery. I spent most of my time in Trago looking at the air soft guns they have in the sporting section, knew I should have bought one BEFORE telling the Mrs about them! She wouldn't let me buy one, meanie!

 

With the fan mounted direct, do you have any problem with paint build up on the blades or do you use a filter? This is the only problem I can see, but as I intent to clean the airbrush by spraying into the extractor I'm hoping the thinners will clean the fan as they pass through.

 

Mark

[AngryMeerkat]

Looking at the B&Q site, the manufacturer of the unit is Manrose. I did a quick Google search - they're based in Slough so I 'phoned them up. All their fans are IP44 rated. When I asked if the motor in the B&Q unit would be an induction motor, the reply was "No, it's just an ordinary axial motor". Surely every motor of any kind is axial as it goes round, or am I missing something? Because of that, I decided to give up asking technical questions of the technical department! I then decided to use Google again to find out what an axial motor is, and I found this link. To my mind, this means an axial motor is brushless and therefore highly unlikely to spark. However, that's a guess - anyone want to shoot my theory down in flames? Please feel free to do so - I'm willing to learn!

 

After I'd been told about the IP44 rating I decided to try and find out what it means. From this link the first figure of the IP44 rating means that the fan is protected against most screws and wires of less than 1mm diameter. The second figure means that water splashing against the enclosure from any direction shall have no harmful effect on the fan.

 

I explained that there is some discussion on a modelling forum about the use of the extractor kit for a spray booth, and the immediate response was that they're not suitable, but surely that would be the natural response if the unit is being used for a purpose for which it wasn't designed. However, to my mind, the unit must be suitable, as I really wouldn't like the idea of having a motor to which water could get access - even though it's a long time since I did 'O' level physics, I do seem to recall that water and electricity aren't natural bed fellows! 

Phil

The reason they will instantly say it's not suitable is it hasn't been properly tested and certified for anything other than it's intended use, mainly due to cost. Because they haven't tested it, and because this country loves to sue people, they have to say it's not suitable. But as you rightly and logically point out, if it's protected from water splashes (quite a bit of water, not just a small drop) then it is a pretty well sealed unit to prevent electricity coming into contact with the water.

 

Mark

[BlackRat]

Not that you would,notice, the first mark 1 used computer 12v fans but were no where near good enough, the second one used an old cheese ripening box provided by Bubbles2 of this forum.

 

Gone posh now with mark 3' it's fully enclosed and I keep meaning to fit a light into it as well.

 

At the mo it is in the loft as it was doubling up as a damp air extractor up there as well!! :-)

 

As a PS, the cable was an extension lead from B&Q with about 5 m of wire with a double socket, just cut the sockets off and wired to the fan! It was cheaper than buying the wire and a plug!!!! :-)

Edited July 21, 2014 by BlackRat

[ian@stenochs]

[quote name="AngryMeerkat" post="1521685" timestamp="1405951807"

With the fan mounted direct, do you have any problem with paint build up on the blades or do you use a filter? This is the only problem I can see, but as I intent to clean the airbrush by spraying into the extractor I'm hoping the thinners will clean the fan as they pass through.

Mark

 

Hi

You do need a filter as there is a build up of paint on the blades and casing which reduces the suck. As I described above a filter made from horticultural fleece works for me.

Happy modelling

Ian.

[Revolution Mike]

Sorry to pee on the anti-H&S brigade that seems to want to poo-poo those who might be concerned about volatile organics and sparks, but unless you know exactly what chemicals are being used by an individual as thinners or at least what VOCs are used in the paint then you really shouldn't be making assumptions that everything will be fine.

 

Flash point is the key and you get some remarkably low flash points with VOCs.  You don't need compression if it is low enough.

 

Chances are that everything will be OK, would I take the risk - not a chance.  I've seen the results of what happens when sparks and low flash points mix - spectacular fires.

 

A handful of hazardous waste treatment plants (which I work on) took similarly lax views on VOCs (a lot of which comes from discarded household paint and similar) and ended up with very melted waste storage areas. Others spend a lot of time and money on extracting the potentially contaminated air (for combustion) and/or use nitrogen blankets if there is any risk of sparks eg in a shredder.

 

Cheers, Mike

[PGC]

Sorry to pee on the anti-H&S brigade that seems to want to poo-poo those who might be concerned about volatile organics and sparks, but unless you know exactly what chemicals are being used by an individual as thinners or at least what VOCs are used in the paint then you really shouldn't be making assumptions that everything will be fine.

 

Flash point is the key and you get some remarkably low flash points with VOCs.  You don't need compression if it is low enough.

 

Chances are that everything will be OK, would I take the risk - not a chance.  I've seen the results of what happens when sparks and low flash points mix - spectacular fires.

 

A handful of hazardous waste treatment plants (which I work on) took similarly lax views on VOCs (a lot of which comes from discarded household paint and similar) and ended up with very melted waste storage areas. Others spend a lot of time and money on extracting the potentially contaminated air (for combustion) and/or use nitrogen blankets if there is any risk of sparks eg in a shredder.

 

Cheers, Mike

 

I understand the problems of chemicals, low flash points etc., but there are several people on this thread who have built these things and used them over an extensive period of time, and they're still writing to tell us about their success, so I guess they're still alive and haven't blown themselves up.

 

It seems to me that a lot of people forget to differentiate between domestic and professional use. In IT, which is the world I operate in, I get to talk to so many people who buy a computer, plug the bits in, power it on and connect it to the internet, so they think they know about IT. What they don't realise is that behind the scenes in a commercial environment you have to deal with firewalls, DHCP and DNS servers, VLANs, switches, hubs, routers, IP addressing, MAC addresses, packets etc., and when the "IT savvy" people are presented with these areas of expertise, they start to realise that in reality they know very little about IT.

 

In the same way, if I was setting up a professional spraying company, would I be prepared to take a chance with a domestic filtration unit? No, but for light use that I'm going to put the unit to, I'm prepared to take the chance, while at the same time being aware that it may not be suitable for use if something happened and I needed to turn to spraying as a profession.

 

To paraphrase Angrymeerkat, "you're not safe walking across a field in Ukraine because a plane might fall out of the sky" (Apologies if this seems in-sensitive, it's just trying to show that the worst can happen, but in reality, what are the chances?)

 

Phil

 

PS - I'm the H&S person at work, and I don't poo-poo them, I just treat the zealous ones as people to steer clear of because they make life difficult for no reason.

[AngryMeerkat]

Sorry to pee on the anti-H&S brigade that seems to want to poo-poo those who might be concerned about volatile organics and sparks, but unless you know exactly what chemicals are being used by an individual as thinners or at least what VOCs are used in the paint then you really shouldn't be making assumptions that everything will be fine.

 

Flash point is the key and you get some remarkably low flash points with VOCs.  You don't need compression if it is low enough.

 

Chances are that everything will be OK, would I take the risk - not a chance.  I've seen the results of what happens when sparks and low flash points mix - spectacular fires.

 

A handful of hazardous waste treatment plants (which I work on) took similarly lax views on VOCs (a lot of which comes from discarded household paint and similar) and ended up with very melted waste storage areas. Others spend a lot of time and money on extracting the potentially contaminated air (for combustion) and/or use nitrogen blankets if there is any risk of sparks eg in a shredder.

 

Cheers, Mike

Sorry Mike but you're comparing apples and oranges when you try to bring industrial paint standards to airbrushing equipment. When you're moving VOCs by the ton then yes, sparks and spark suppression really do need to be addressed and they are in industrial booths. However for somebody airbrushing models at home the same rules are totally impractical and could never be introduced. Lights, plug sockets, airbrush compressor, the radio, a TV, a DC or DCC controller, all of these things are present in the room of an average modeller who uses an airbrush, and none of them have any kind of anti-spark system fitted. An industrial booth moving 50L per hour is very different to an airbrush moving 40cl per hour! This isn't 'Anti-H&S' this is common sense! By industrial standards all modellers who use paint should have died years ago in a massive fireball that destroyed a whole city as we don't have SSS or anti-static paint storage, in fact many modellers don't even have any form of extraction when painting!

 

I'm purposely NOT pushing a H&S element in airbrush extraction as I'm treating people on this site as adults who can understand the difference between painting a few scale models every year and spraying 30 full size yachts and their interiors every year, which is my current employment. I fully understand the requirements when using paint in an industrial setting, and I fully understand they bear very little relevance when using an airbrush at home for spraying a few small bits as a hobby. What next, people shouldn't use an airbrush unless they are wearing a spray suit and air-fed mask? Everyone must store their paint in an anti-static earthed paint cabinet?

 

By all means educate people in common sense when using paint, but scaremongering is counter-productive.

 

Mark

[Revolution Mike]

I understand the problems of chemicals, low flash points etc., but there are several people on this thread who have built these things and used them over an extensive period of time, and they're still writing to tell us about their success, so I guess they're still alive and haven't blown themselves up.

 

It seems to me that a lot of people forget to differentiate between domestic and professional use. In IT, which is the world I operate in, I get to talk to so many people who buy a computer, plug the bits in, power it on and connect it to the internet, so they think they know about IT.

 

My point was that there are quite a lot of waste plants which deal with VOCs with little particular protection, some of them have had some fairly spectacular fires in their bunkers - albeit a small minority. By anecdotal evidence you might not bother taking many precautions.

 

The IT analogy is a bit crass, when you compare the consequences of things going wrong.

 

Sorry Mike but you're comparing apples and oranges when you try to bring industrial paint standards to airbrushing equipment. When you're moving VOCs by the ton then yes, sparks and spark suppression really do need to be addressed and they are in industrial booths. However for somebody airbrushing models at home the same rules are totally impractical and could never be introduced.

 

I'm not talking about moving VOCs by the ton though, in fact the exact opposite - a relatively small amount of VOC in the right/wrong place at the right time! We're talking about small amounts of VOC in massive waste storage bunkers which got close enough to a spark to start a fire. The point is really: is there the potential for low flash point materials to get close enough to a spark to ignite (and what would be the consequence of that)? I suspect in domestic use the worst that you are going to do is knacker the motor, but I'd rather avoid that if possible!

 

Cheers, Mike

[BlackRat]

I'd better stop licking my fingers and placing them on the track to see if I've got power then!!

[JeffP]

Wot's Trago Mills? Anything like Dunelm MIlls?

[Ramrig]

Wot's Trago Mills? Anything like Dunelm MIlls?

 

Try here

http://www.trago.co.uk/

 

quite a long way from Scunthorpe though.

[Barnaby]

......... or you could use brushless motors. 

[Londontram]

Wot's Trago Mills? Anything like Dunelm MIlls?

Hello Jeff both a tourist attraction and a super store, seem to recall a fair model railway there. Worth a look if your in the area