I'm considering buying a spray booth

[Guest]

Steve

I would not put anything into a wall or the roof space. Think you are asking for problems both fire & contamination building up over time. It will taint all it comes in contact with. White spirits that is.

I modified mine with a bathroom ventilation ducting from B & Q. Can you vent with ducting up into the roof space then out through the roof tiles. You can get roof outlets especially for this. Or if your eaves overhangs the outside wall you may be able to put a hole in the sofitt & fit a duct outlet. B & Q again.

LAurie

[Guest]

tecdes: Thanks. I don't think the ventilation into the roof space then out through the tiles would be practicable in my case. The tiles are, I think, made of asbestos cement and are tricky to play about with, and I think I would have to pay a builder with some scaffolding (unless he could do it by leaning out of the window).

Alternatively, the window is one of those that rise out of the roof surface with the glass vertical (of course) with two reveals, one on each side. These reveals are made of wood tongue-an-groove inside and some sort of roofing felt or similar on the outside. They face the outside and I could easily put an exhaust hose through one of them, although again a builder would have to fit a weatherproof seal on the outside, hopefully without scaffolding. This seems the best solution.

Changing to acrylics would probably not help. There would be no fire hazard from the fan but I would still have to expell into fresh air because of the contamination problem that you mention.

In the meantime, until the problem of a booth is sorted, I will do my painting in the garage, although the low temperature in Winter could cause problems.

[Ian M]

Which ever solution you choose, be sure to place the outlet in a place that will not allow the fumes to be blown back into the room in the summer if you have open windows. Or worse blow out into the neighbours.

do you have a picture of this window area, it might help some one come with a suggestion.

Ian M

[Guest]

Steve I ran an architectural practice for 50 years but can only really help if you could publish here some pictures giving info.

One the outside of the house near your eaves pointing out the window you are talking of with the level of the eaves compared to the floor level.

One thing for certain. If you poke this end of the vent out of the window you are defeating the purpose. As you pump out air in a room it will need air to replace it. As it goes out of the window guess what comes back in fresh air mixed with a percentage of the air you have just extracted. So if you dangle it through your window block the remaining gap with a towel or something.

Also bit of experience. If you look at a sunlit shaft in your room from a certain angle you will see loads of bits floating in the air. If the air is still that is OK. Open a window, a door & close a door quickly those bits will fly every where. Same with using a vacumn cleaner it stirs the air more than anything. I bought a pound shop bottle with a moisturizer trigger thing. Spray five minutes before with water which clears the air around your spray booth.

Laurie

[Ian M]

I think the pipe out the window will be ok in itself as long as the end of the pipe is far enough out of the window. I had not thought of the back draft stirring all the dust up though.

Ian M

[Guest]

I bought a pound shop bottle with a moisturizer trigger thing. Spray five minutes before with water which clears the air around your spray booth

Good idea which i've used a few times ...... another good one is to boil a kettle in the room just before spraying, the steam drops the dust to the floor and the slightly elevated humidity can be advantageous to the spraying of acrylics (auto spraying booth trick)

[Guest]

Good grief, you learn something new every day.... I just go out into my little 6x4 plastic shed, turn on the heater if it is cold (I have worked out there when it was minus 5 wearing my shorts and T shirt in comfort 10 minutes after switching heater on. Not an image to ponder on I may add) and spray away to my hearts content. I do have a mask though and I do have a standard extractor fan in the shed

[Guest]

tecdes: Here is a sketch of my house layout. (Hopefully it will appear.)

[ATTACH]53438.vB[/ATTACH]

One thing seems clear: in principle, if a paint is being used with a flammable solvent (e.g., enamel), an inexpensive (and therefore mains-powered 230 V) booth of the type I referred to at the beginning of this message cannot safely be used whatever the exhaust system chosen (although messages on this and another forum indicate that it is being used with no reports of explosions or fire). Other booths are available with the fan motor safely outside the exhaust path but they are too expensive for me.

Solutions to the flammable problem (if it is significant):

1. Homemade booth with a 230 V 6" office desktop Fan or a 230 V kitchen extractor fan. The distance between the end of the motor housing and the blades is too small to allow the motor to be out of the exhaust path without a shaft extension or a right angled bend in the transmission shaft which would be engineering projects in themselves. However, perhaps a circular baffle between the blades and the motor (perhaps curving back using a large truncated plastic bottle) would deflect the exhaust stream around the motor. Worth considering.

2. Homemade booth with a USB desktop Fan or a USB computer cooling fan. This being low voltage might be safe. It needs a mains-to-USB power supply. However, the computer fans available don't seem to give enough airflow, although I saw a video of a home-made booth with 6 such fans.

3. Change to Acrylics. This would allow a mains powered fan system to be used (although are there solvent-type acrylics?) I have no experience of acrylics. Can acrylics produce as good and smooth a paint finish as enamels?

Expelling

4. This leaves the question of expelling into my roof space, enamels or acrylics.

[ATTACH]55771.IPB[/ATTACH]

[Guest]

Stevekir again: I have been researching the use of a 12 V DC computer fan. One in the US:

5.5" x 5.5" (140mm) CoolMax Chameleon CMF-1425-MU Coolmax CMF-1425-MU Chameleon

12V, 144 mm, 69 Ft3/min (CFM), current consumption not specified, 2.99 USD. Two would give enough airflow I think, but I read elsewhere that the pressure is a factor. If it is too low for passing through a filter and the exhaust hose at a good rate (it is designed to pass through the case of a computer which has some obstructions to air flow) it would not be suitable.

A 230 VAC/12 VDC (regulated) power supply from:

Power supply for 12V 0.6A | Allbatteries.co.uk

would provide 0.5 A and cost £9.90 including VAT.

I'm thinking that this is the way to go.

This leaves the question of the exhaust route (outside or in roof space).

Anyone has any comments, esp. tecdes?

[stona]

I'm writing this as an ex-chemist,not a health and safety expert.

If you,in the normal course of spraying solvent based model paints,using an airbrush,can develop a concentration of flammable fumes in the air of your model room/spray booth which might explode I will eat both my shoes.

I bet enamel paints,even in an aerosol from an airbrush,are difficult to even ignite,let alone create an explosive mixture in air. Vapour explosions depend on a lot of different criteria beeing met and are not as easy to create as you might expect. I worked with a lot of organic solvents in my time.

Mmmmm,I feel an experiment coming on!

I would try an exhaust to the outside if possible.

Cheers

Steve

[Guest]

Thanks stona. But if the roof space has electrical cabling to a light over, say, the porch, a spark (unlikely) might cause a problem. However, I expect that the fumes would be hugely diluted by the time they were expelled into the space, and anyway I would be airbrushing for a max. of, say, two minutes at a time, repeated, say, 6 times, all over several hours. and the space is quite well ventilated due to the lack of any tarpaper lining under the tiles.

However, still thinking.

[stona]

69 cubic feet per minute is 4,140 cubic feet per hour. My Exagon spray booth moves 355 cubic metres per hour which works out as 12,537 cubic feet per hour,about three times as much as you are proposing.

Just saying.

Steve

[Guest]

I do that to keep kids out of my den

That's the one I use too Steve, excellent mask for keeping out the nasties.

With this mask on I can sit in the shed and after using some strong cleaning solvents I'm totally unaware of the smell in the room until I left the mask off, that's how good the filtration is on this one. After 5 mins the extract has cleared the room anyway but combining both gives good protection. The extract I use is the Graphic Air 300.....

GraphicAir A300S-D Air Extraction Cabinets | Air Extraction Units

Very good but not the cheapest. I do like the look of the Exagon which I believe Steve uses but it was not avaliable when I bought mine...

Exagon Spray Booth - Graphic Air

You must make sure the fit is correct though otherwise as Laurie points out you can get leaks around the mask to face edge. One way of checking correct fit is when wearing the mask place your hand flat on the intake valve and breath in gently, you should feel the mask sucking to your face the harder you breath in, then you know your air tight. This is how we were trained to use respirators at work so we can work on chemical cleaning tanks safely.

I also use this mask at work when working in a dusty carbon environment when replacing industrial motor brushes - very dirty job!

Colin.

[stona]

Excellent Colin,I'm not the only fashion victim then :lol:

Very good advice about the fitting of the mask,something I learnt as a young chemist. I really do think people should use a mask. The absence of smell does not mean the absence of things that should not be inhaled. You only get one set of lungs so why take the chance? Times are straightened and money is always tight but it is a relatively minor investment,certainly compared to the rest of the gubbins you'll need for spraying.

I do use the Exagon spray booth and absolutely love it. It wasn't cheap but it works very well and will hopefully last for many years. I'm one of those who sprays standing up and the Exagon booth will sit at about 45 degrees,perfect for me to spray into.

Cheers

Steve

[Guest]

tecdes: Here is a sketch of my house layout. (Hopefully it will appear.)One thing seems clear: in principle, if a paint is being used with a flammable solvent (e.g., enamel), an inexpensive (and therefore mains-powered 230 V) booth of the type I referred to at the beginning of this message cannot safely be used whatever the exhaust system chosen (although messages on this and another forum indicate that it is being used with no reports of explosions or fire). Other booths are available with the fan motor safely outside the exhaust path but they are too expensive for me.

Solutions to the flammable problem (if it is significant):

1. Homemade booth with a 230 V 6" office desktop Fan or a 230 V kitchen extractor fan. The distance between the end of the motor housing and the blades is too small to allow the motor to be out of the exhaust path without a shaft extension or a right angled bend in the transmission shaft which would be engineering projects in themselves. However, perhaps a circular baffle between the blades and the motor (perhaps curving back using a large truncated plastic bottle) would deflect the exhaust stream around the motor. Worth considering.

2. Homemade booth with a USB desktop Fan or a USB computer cooling fan. This being low voltage might be safe. It needs a mains-to-USB power supply. However, the computer fans available don't seem to give enough airflow, although I saw a video of a home-made booth with 6 such fans.

3. Change to Acrylics. This would allow a mains powered fan system to be used (although are there solvent-type acrylics?) I have no experience of acrylics. Can acrylics produce as good and smooth a paint finish as enamels?

Expelling

4. This leaves the question of expelling into my roof space, enamels or acrylics.

Wow that is comprehensive for some one not in the business Steve. You understand 3d & that is not easy.

Out thro the eaves. Problem is you will have to demolish the plasterboard wall to get your ducting to the eaves. Also your eaves need to be approx 6" wide to cut a hole in & leave a bit all round.

Thro the side of the dormer seems best. If so cut on the east elevation or as near east as possible. Less wind & better sheltered that side. You need a down looking extract exit externally for weathering. Also who ever does it make sure you get a good seal between the dormer material & the extract. Giving this without full knowledge & seeing the site.

For me I would not mess with my own solutions as it is fraught with problems.

Also remember that you are passing air with a fan in the path of the piece that you are spraying. Every piece of hair in the air passes the piece being sprayed.

I changed to acrylics for enamel when I was in my modelling infancy (am I past it ?). The paramount reason was the awful small, despite my fan spray booth & feeling not so good after a good spray. I now use only Vallejo Acrylics for both these reasons as it is non toxic & does not smell. Best paint I duno as have not used othere top Acrylics but it gives a great finish for me.

Laurie

PS An extracto fan of the kitchen variety will suck you & the dog into the ether.