Thread: any ideas on building your own spray booth ?

Like everything else you will only get what you pay for. The more you cough up the better system you will get But

Think out exactly what you really are trying to achieve, its easy to remove fumes and overspray but it can be done better if you set it up properly.

Going straight up through the roof is the worst way to do it. You have to have a fan strong enough to overcome gravity and particles will tend to fall back down onto your work and the overspray goes up past your face as it is sucked up.

The best way is to have a fan draw the air low down so the falling overspray gets pulled away from you and everything ends up on the floor not in the air. To do this you need to have planned ahead far enough to make it possible to do this. Probably you have already a floor which won't be easy to put in exits below it so you will have to use the second best method where you draw the air out through the side or end of your room.

You will need an opening at one end with a filter on it to allow air to enter and at the other end a fan behind a filter to catch the overspray before it leaves the room.

I presume you are doing this for yourself so you can make it to your liking but booths have a lot of rules as to how and what can be done such as fire proof materials for walls etc flame proof lights, minimum air movements, exhausting of fumes to atmosphere. ( how are the neighbours going to react ?)

If you intend doing lots of work in the booth a bit of research and money will make it a far better set up, if you are only doing the odd job a simple fan to move out the fumes etc would work.

There are portable booths available which consist of a frame with plastic covering and an exhaust which work for the odd respray. I would look around for a second hand booth being replaced to see if you can get parts from it to use. Our work replaced 3 booths and the old ones were still in great condition and they just scrapped them because no one at the time wanted one. If they were available now I would grab one as it would make a great shed without the actual workings.

Jake,
just be aware that lacquer fumes are potentially flammable/explosive and any lights and motors in your booth need to be approved for use in explosive environments. I spray under a tarp outside

Mick

Mick,

How do you avoid dust settling on your newly sprayed surface when spraying outside?

/M

thanks for the advice. Didn't put much thought into drawing the air down. Or the explosive proof motors. They sound expensive.

I'm buying myself a new Ranbuild shed. Biggest I can go for my back yard. 10x11metres. No dust extractors, so I really gota keep the dust away.

My Initial thoughts is to knock up a couple of walls inside the shed, to form a small room about 3 x 5metres to use as the spray booth. Totally closed off from the rest of the shed. To get in you walk outside through one roller door and then through another to get into the booth. At the end of this little room I was going to setup the booth, and just spray my chairs on a spinning frame and layoff my chairs further up towards the door.

Early days though. Can change the door layout etc. If anybodys got any ideas I'd appreciate it.

Originally Posted by seafurymike

Mick,

How do you avoid dust settling on your newly sprayed surface when spraying outside?

/M

Never had a problem, the lacquer dries in minutes and there's never much dust around. It would b a problem if spraying somehing slow drying like enamel or polyurethane but lacquer dries so fast that you'd have to be spraying somewhere quite dusty for it to be a problem.

Mick

You could always stickup a supercheap autos portable garage for spraying in wet weather.

As said above sprayboth set up properly will cost you as much as your entire shed, if you enclose a room with no extractor fan you are creating a bomb waiting to explode, also roller doors will not keep dust out without a lot of sealing around the edges. I think you will find the tarp outside the most pratical option

If you are only spraying lacquer it will be a lot easier to have an effective booth area. When lacquer was the prefered paint on cars panel shops never had booths they sprayed up one end of the shop or if you were lucky in a separate shed but fans/booths were unheard of. Only shops doing enamel work had those and some only had an area they hosed down to lay the dust before spraying.

When lacquer dries it evaporates large quantities of solvent quickly so a good fan set up would keep the room free from solvent fumes. The easy way to have a cheap fan without the problems of sparks maybe igniting the fumes is to have a fan that is belt driven. The fumes can be drawn out by the fans but won't pass near the motor as you can isolate it outside the tunnel the fan is in by driving it by a belt with just a small gap in the tunnel for the fan pully to drive it. Most expensive booths use this type of system otherwise you have to have a flame proof elecric motor and they are expensive.

If you put glass in the walls and place your lights on the out side of them then you will have flame proof lights as they will be isolated from the fumes. Another way is to make a box with glass in it, put the lights inside and place a fan at one endand blockof the other end. This will pressurise the box making it impossible for the fumes to get to the electrical connections. The fan would be on the outside of the room so it got fresh air..

As mentioned lacquer dries so fast very little dust gets a chance to contaminate it. If you seal off any openings from the outside and then keep the interior clean ( make it so its easy to wash out with a hose ) you will have a nice dust free area to work in.

As China states roller doors are hard to seal off so how about making a room in the corner with a hinged door (which will be easy seal) to get in and to load in your work. Then put the fan on the wall at the end and an inlet for air on the outside wall at the far end furthest from the fan. If its easier for the fan do draw air from that than anywhere else it won't tend to suck any dust etc from the rest of your shed.

thankyou kindly for all this help.

You mean something like this (picture) ?

I understand the need to pull the rising fumes out ( with the flow between the two windows)

So put the filter low like in the picture ? And the fan that pulls the air through that will have to go out the building as well I spose ? , or can I direct it up to mix with the high air flow and out that way as well ?

Bit worried I'm going to cock this up. Maybe I should buy an old booth after all. Thats going to cost dollars I can't really afford I think.

Been away for a week, you are pretty right.

The filters are for two reasons, if the air outside is dirty you need to filter it so you don't get dirt in the air passing over your job.

Or you need to filter the air leaving the booth to prevent the overspray from being a problem to the neighbours etc you would put it in front of the fan. So filter in the wall, fan outside of it behind the shed in its own box. ( if you have room behind, if not at the end of your room) You won't stop the smell of the solvent but if you used enamel it would stop paint getting over objects close. Lacquer is lees of a problem as it dries so fast you will only be putting dryspray /dust into the filter. You may need both before and after.

Instead of a window you could mount the filters in the wall so air had to pass through it to get inside and you could have no window or leave it closed. The filter material is similar to insulation wool or scothbrite so it can be washed a few times before it needs replacing. You could use any material to catch the overspray but the proper kind works best. To get real clean air we use silk screen cloth in front of the filter material, you could use muslin or similar to help prolong life. Just remember that you want the air to flow through well so you don't want to choke it up with a filter air flow that is restricted too much.

It is also possible to pass the air through a water wash this is a waterfall that the air flows through but requires more costly gear ( big fan, water trough, sheet metal chimney) but it does work better neally 10% clean air and you only have to change the water when it gets really dirty in your case that could be years.

Thanks mate. Makes sense now. Owe you a favour for all that help.