Container spray booth build?

[Albert]

I am new to spray finishing - be kind..

I have been told to achieve quality spray finish you need quality spray guns, therefore I have been looking at fancy spraying guns but realised I need a proper booth to go with the proper gun.

My current compressor is Chicago Pneumatics CPRS10500, does 43CFM, its a 10hp with a 500 litre tank. The refrigerator and filter are Ceccato, they were spec'ed to match the compressor. I guess my compressed air ends are sorted.

I am planning to build my own spray booth using a small container type storage like the one below and extract the air from my existing dust extractor, the cost for this storage will be about $2500NZD. I have no room in my workshop. this will be sitting on my driveway next to the workshop.
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my questions are:

Can I use my existing extractor to pull air from the booth? Will the filters similar to the one below be adequate to catch most of the paint so it doesnt destroy my extractor filter? the extractor is a 4kw unit, the filter cost about $700NZD, the filter below measrues 1200mm x 500mm x 250mm deep.

PFB-1200-500x500.jpg


or do you recommend have dedicated fan for it? I may just use 2 of these portable unit, will my neighbour smell anything once I hooked up a fan to it? the cost for the fan is about $200-250 NZD each.

PVF-300-500x500.jpg


Will I be able to have my spray booth built under $5000NZD and keep the neighbour happy? or can it be built more economically and still keep the neighbour happy?

What will I be spraying? I dont know at this stage. I am yet to find a suitable finishing product for the furniture I build. Probably shellac or water based polyurethane?

Thanks.

[Cliff Rogers]

Good ideas, I reckon that the dust extractor may not shift enough air & I would be worried about the filters.

These things are always a problem in suburbia.

I'm in the bush so I don't have problems with noise or dust upsetting the neighbours.

My biggest problem is the air intake, not the extraction.

The air up here can be VERY wet, we are just below the cloud base & sometimes we are just above the cloud base so anything that draws air in brings cloud/mist in with it.

[Chris Parks]

Albert, have you thought about the supply of air needed and how you are going to filter it? Most spray booths these days are down draught and I believe use water to trap the solids. I would be wary about any neighbour reaction to the exhaust as this is, in Oz at least, a very closely regulated thing due to the emission problems. I would be taking a very long hard look at all the issues as spray booths are not cheap for good reasons.

[BobL]

Definitely don't use your dust extractor or the fumes will clog your DC filter.

In terms of fans I would look at using squirrel cage fans (SCF) as they are high volume and much quieter than axial fans.

It depends on what volume of spray painting you intend doing.

If you are doing it full time then you will need something serious like Chris suggests.

If you are only doing occasional sprays then a specific paint stop filter like Vokes media will probably be sufficient.
See :: AES Environmental online :: Roll media
While its very effective I would still not trust it to prevent DC filters from clogging

There is nothing really fancy about paint stop media other than it is a low resistance graded density filter medium.
Similar and cheaper versions can be found that are not specifically for paint that work almost as well.

I have a small welding bay fume hood that I sometimes use as a spray booth.
It uses a single 0.75 cubic metres per sec SQF and when painting I place a square foot of AES Environmental H media in front of the fan inlet and it seems to capture all the paint spray i.e. can't see any colour getting past that. The filter lasts for about 10 small paint jobs and then needs to be chucked away. Fortunately I have a big roll of the stuff that should last a lifetime. I reckon most of the clogging comes from dust in the air sticking to the paint rather than the paint itself.

Something you will need to keep in mind is pressure losses due to the paint load
When new the 2" thick paint stop media has a pressure drop of 35 Pa at 2.5m/s
2.5 m/s x 0.36m^2 (or 2 ft x 2ft) of cross sectional capture area ~1 m^3/s (About 200 CFM) which would be possible with two smaller or one larger SCFs and the 11 Pa plus the additional load cause by the dried paint should be easily coped with by the fans.

[ian]

Hi Albert

What sort of system are you considering? HVLP or LVHP?

What material will you be spraying? Especially in regards to the solvent.
Some represent an explosion risk unless the electrics in any fan are protected -- the cheap axial flow fans may not be suitable for some solvents.

Perhaps investigate professional finishers in Auckland

[woodPixel]

Are you spraying just furniture?

Thats a mighty setup for an individual. I'd be interested to know how it all goes.

I spray nitro, oil and water paints, and poly in my impoverished setup..... a market gazebo/tent with the fine mesh sides! A remote breather so fumes don't do me in and a garden hose in the summer for dust

Keeps out all the bugs, dust and specs aren't an issue either... but then again I'm not refinishing Louis XIV bombe!

more pix as you progress please!

[Albert]

I am going to put the filters at the intake grills, just like the ones they use at the professional booth? I have thought about down draught and use water to trap the solids/paint but this is quite tricky. over here it is very strict as well, been researching online on this...

[Albert]

Definitely don't use your dust extractor or the fumes will clog your DC filter.....coped with by the fans.

Thanks Bob. I have ruled out the use of my dusty. am trying to find good filtering media and the resistance lost, wouldnt want to draw too much air so the paint just float away as I spray and dont want to draw too little...

[Albert]

Hi Albert

What sort of system are you considering? HVLP or LVHP?

What material will you be spraying? Especially in regards to the solvent.
Some represent an explosion risk unless the electrics in any fan are protected -- the cheap axial flow fans may not be suitable for some solvents.

Perhaps investigate professional finishers in Auckland

I will be spraying HVLP, material wise I think it will be limited to water based paint for now but I would like to build it so I can paint other stuff, yes they will need to be explosion proof... I know there are explosion proof fans but not so sure how the shed can be built to "explosion proof"

I had a look on the fans, itself could cost anywhere between in the region of over $2000-$4000 brand new.

Might try second hand.

[Albert]

Are you spraying just furniture?

Thats a mighty setup for an individual. I'd be interested to know how it all goes.

I spray nitro, oil and water paints, and poly in my impoverished setup..... a market gazebo/tent with the fine mesh sides! A remote breather so fumes don't do me in and a garden hose in the summer for dust

Keeps out all the bugs, dust and specs aren't an issue either... but then again I'm not refinishing Louis XIV bombe!

more pix as you progress please!

Yes I am just spraying furniture, just trying to do it right to minimise the effect on the environment... live in a residential neighbourhood.

I wish I can set it up like yours but I cant! I need a permanent setup so I can walk in and start spraying.

[Arron]

This is just a thought, so it might be irrelevant depending on your experience level, but....

It seems to me that building a spray booth when you have limited experience of spray painting and don't even know what products you will be using is a bit fraught. Would it make sense to hire a booth for a few times first. Here in Sydney you can hire a booth for about $100 per hour, and naturally it's discounted for a full day. You could do that for a few times till you have a feel for it, then build.

In some cases you can even hire a spray painter as well for $90 per hour. That seems like a good idea because spray painting has a learning curve and just seeing it done and being able to discuss with a expert rockets you up the learning curve.

Or you may even decide not to turn your home into an industrial site and just rent one when you need it, ongoing.

Cheers
Arron

[BobL]

I will be spraying HVLP, material wise I think it will be limited to water based paint for now but I would like to build it so I can paint other stuff, yes they will need to be explosion proof... I know there are explosion proof fans but not so sure how the shed can be built to "explosion proof"

I had a look on the fans, itself could cost anywhere between in the region of over $2000-$4000 brand new.

Might try second hand.

The motors themselves don't need to be explosion proof if they can be separated from the fans like this.
This chemical fume hood ventilator is considered explosion proof because the motor is not inside the fan, the fan body is non-sparking (PVC) and the squirrel cage (in this case is metal) but it could also be plastic.
Its about 50 years old and I found this in a skip at work following some lab renos. T
here were at least 3 others there that I could not get at.
It's only 600 cfm and it had a 3P motor which I replaced with a SP clothes drier motor
I gave this blower to my son for his shed as he does a bit of spray painting of small stuff - he does not bother to filter as the volume of paint he uses is very small.
The whole unit sits in a lean to outside his shed and the horizontal inlet goes through the shed wall.

[Albert]

This is just a thought, so it might be irrelevant depending on your experience level, but....

It seems to me that building a spray booth when you have limited experience of spray painting and don't even know what products you will be using is a bit fraught. Would it make sense to hire a booth for a few times first. Here in Sydney you can hire a booth for about $100 per hour, and naturally it's discounted for a full day. You could do that for a few times till you have a feel for it, then build.

In some cases you can even hire a spray painter as well for $90 per hour. That seems like a good idea because spray painting has a learning curve and just seeing it done and being able to discuss with a expert rockets you up the learning curve.

Or you may even decide not to turn your home into an industrial site and just rent one when you need it, ongoing.

Cheers
Arron

Thanks Arron, I have considered hiring a spray painter to spray paint my product, the painter has a proper booth setup but the cost is exorbitant - I guess it is because its labour intensive?

It is a good idea, to rent a booth first to see how I go then build.

or not spray paint finish my product at all.

[Arron]

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or not spray paint finish my product at all.

No, you need to spray. Nothing in a small scale woodwork business is more profit-enhancing then spray-finishing.

Cheers
Arron

[Albert]

exactly... I have already invested in some good gear for the compressor setup, I dont mind to spend extra $$$ on a proper shed, a fan and filter, if my initial budget of $5000 is not enough to obtain optimal solution (optimal as in minimum disruption to the environment, been looking at regulations in NZ they are all aimed at industrial operations, you can spray paint at home as a hobbyist but you can not spray paint like a full time job)

I have been asked too many times by my client why is the work semi finished, ie, not painted - I had to makeup reasons such as, we let the client to choose their finish as most clients would like to do some DIY themselves...etc etc.