Paint Booth Air Extraction

[Snowy90]

Hi All,

I have a paint booth set up in the garage, nice and sealed and appropriate spark proof lighting, ive only used it for small jobs. Air fed mask all set and regulator with coalescent filters etc.. compressor in fresh air.

It has two inlet fans as was hoping to set up a positive pressure system but when i put 3M filters on the inlet they do not let enough air through to positively charge the booth. I have a paint catcher across the exit vent and filter panel beyond that.

So i was thinking of putting in a extrtactor on the exit, i apreciate ths may not maintain possitive pressure in the booth but would hopefully clear the paint and minimise the overspray.

Todate i have been paranoid about using explosion proof lighting and keep plugs and switches outside, I have a vivid imagination and do not want to go up in a huge ball of flame! However, such rated extractors are £3-400 which seems excessive, i appreciate that there is no price for safety.

But i was thinking of using the clarke type blower extractor which are not explosion proof, with the ducting attached to the booth and the fan at the garage door opening about 2m away.

I welcome your thoughts and if anyone uses a similar setup.

 

[julianf]

If you're wanting positive pressure, could you use a cheap blower on the end of a long pipe? If you are really worried about solvent fumes getting back to the motor when it's not running, fit a gate valve to close when not in use?

But it would be blowing in unfiltered air. I don't know if that is a problem for you.


I'm thinking bouncy castle blower cheap. About £30 ish (I got two, used, off eBay for a tenner once - tenner for the pair, not each)

 

[Cuthy246]

I stand to be corrected, perhaps @Parm can contribute, but are paint booths not supposed to run at a negative pressure to prevent fume escape in the event of a poor seal?

 

[carbon]

This has publication is aimed at spraying isocyanates but recommends negative pressure http://www.hse.gov.uk/pubns/priced/hsg276.pdf

 

[jack-daniels]

Todate i have been paranoid about using explosion proof lighting and keep plugs and switches outside, I have a vivid imagination and do not want to go up in a huge ball of flame! However, such rated extractors are £3-400 which seems excessive, i appreciate that there is no price for safety.

But i was thinking of using the clarke type blower extractor which are not explosion proof, with the ducting attached to the booth and the fan at the garage door opening about 2m away.

I welcome your thoughts and if anyone uses a similar setup.

My mate put two of these

in his spray booth 15 years ago (as well is an inlet fan & filter) and has used it daily since.

He also used normal fluorescent lights, switches & sockets and was still doing so last time I saw him.

I'm not advising anything here, just relaying a real life situation.

Oh, he also had one of these in there as well.

 

[Snowy90]

Tricky one, positive pressure is ideal as dust and other contaminants are kept out and not sucked in, whilst i think its sealed clearly in a garage nothing is sealed.

But your right if spraying 2k then keeping the nasty stuff in may be better, i haven't and dont really want to spray 2k but never say never ( so long as the safety procedures are followed.

Those clarke fans look good and may well force the air in through the inlet filters better than mysetup which uses two strong horizontally mounted floor fans, does a great job until i place the filters in.

In my mind the risk is very low, ie paint catchers and filters before the air would even get to a fan.

I really want one of those car lifts! I just do not have the height, maybe if i swap the landie for a sports car!

 

[Snowy90]

Julian, that was the plan use a long duct and a extractor on the end and suck it all out

 

[julianf]

To be sure, I did not suggest a long duct and an extractor. I suggested a long duct and a blower.

An extractor would still be running in fumesz no matter how long the duct. A blower will not be.

 

[Rig Pig]

I stand to be corrected, perhaps @Parm can contribute, but are paint booths not supposed to run at a negative pressure to prevent fume escape in the event of a poor seal?

Yes, otherwise poisonous/flammable fumes will leak out of the doors!

 

[Rig Pig]

If you look at a proper spray booth it has big inlet and extract fans with dampers to adjust the flow and allow you to keep it just negative.

 

[Parm]

I stand to be corrected, perhaps @Parm can contribute, but are paint booths not supposed to run at a negative pressure to prevent fume escape in the event of a poor seal?

I haven’t read any the post above, but oh yes. Should definitely be under negative pressure. If it isnt then there is something wrong. Balance make up air should be grills only. If fans are used to supply make up air this becomes a push pull system, Never ever found in spray booths. In fact push pull systems are only normally used in firing ranges

 

[carbon]

I may not be correct on this but it does look like america has paint booths that run at positive pressure or did.

 

[Parm]

If you look at a proper spray booth it has big inlet and extract fans with dampers to adjust the flow and allow you to keep it just negative.

Yep found in spray bake booths.

 

[pedrobedro]

Bouncy castle blowers shift a lot of air

 

[brightspark]

Bouncy castle blowers shift a lot of air

I have quite a large one BLOWER that is probably flog it for 35 quid as its 2 big for anything I want it is 110 volt mind and runs of a yellow tranny

 

[Snowy90]

Hi All,

I have been away, sound lke i should relook at my design, to be fair, im sure its not 100% sealed so will probably get neutral pressure anyway main thing is i want to get overspray out of the booth, as the last thing i painted the overspray just settled on the job and resulted in alot of polishing. Thanks for the offer Brightspark will have a think.

I think a few test pieces are the order of the day and try different fan/blower positions.

Thanks for all of the useful input, i will let you know how i get on and put a few pics of my set up on here.

 

[delta9]

Use water to help with dust, before I spray, my booth get a good dousing of water, walls and floors, and parts of the vehicle that are not getting sprayed. Even the car manufactures spraying plant use water curtains to keep dust down. Not everyone can afford a proper downdraft booth But they are not exempt from dust too... You wont stop the dust, but this will limit it.

I have used normal wall fans (not explosion proof) extractor fans, not had any problems.

Also you want to re-circulate the air after spraying - during the air drying process i.e overnight, particularly useful during the winter as you should have some sort of heater, you don't want that lovely hot air wasted to outside.

 

[The Z'eer]

Hi All,

I have been away, sound lke i should relook at my design, to be fair, im sure its not 100% sealed so will probably get neutral pressure anyway main thing is i want to get overspray out of the booth, as the last thing i painted the overspray just settled on the job and resulted in alot of polishing. Thanks for the offer Brightspark will have a think.

I think a few test pieces are the order of the day and try different fan/blower positions.

Thanks for all of the useful input, i will let you know how i get on and put a few pics of my set up on here.

Glad to see this topic being discussed I too have some questions similar to yours. Firstly with regards to negative pressure, as quoted from Parm and from what I've read so far via the net it works far better to extract air (by force) rather than induct it. It's essential for FAST removal of overspray. Negative pressure will do this where as positive pressure won't do it as well.

Great to hear you've purchased explosion proof lighting, might I ask what type you are using? I ought to purchase some myself, though the jury is out on this one at present. However I am looking at this for extraction https://www.ebay.co.uk/itm/Heavy-Du...413648?hash=item5b4721ae90:g:nXEAAOSw6-xa7GIy but there's no specific ATEX rating (i.e zone 1 etc.) and this is could be why is these units relatively cheap compared to others that do list full certification and spec.

 

[The Z'eer]

My mate put two of these

in his spray booth 15 years ago (as well is an inlet fan & filter) and has used it daily since.

He also used normal fluorescent lights, switches & sockets and was still doing so last time I saw him.

I'm not advising anything here, just relaying a real life situation.

Oh, he also had one of these in there as well.

I'm all for health and safety and hence the reason all professional booths use explosion proof equipment, though I know someone who operated commercially for sometime like the fella you mentioned. Also, when 2K was introduced into the automotive refinishing industry all those years ago, how many businesses were using explosion proof equipment I wonder, probably not many. The question is just how many encountered serious issues. I think it's a bit of gamble, the odds are unknown but consequences could be dire.

 

[Snowy90]

Z your not wrong! that why so far i have sealed lighting RS sell them but i managed to steal a couple of 6ft ones off ebay they are floro tubes not LED but are very good and great light.

https://uk.rs-online.com/web/p/hazardous-area-light-fittings/4067940/

As i have made as much ATEX compliant it would be silly not to go the same route for extraction.

I may not use mechanical extraction and let downward flow of air to naturally remove the fumes/vapor out, i have tried a few smoke tests and it seems to work ok, but i have had terrible issues with overspray in the past so really want to clear the air asap so some form of mechanical extraction would be idea.

I am still thinking a portable blower/extractor on the end of the long ducting attached to the booth, is the way to go. and may have to fork out for an atex one?