Spray booth build

[mahomo59]

Time out from the kitchen build. Had my friend Ross this week for helping on a kitchen build, however Friday was always set aside for fry up and spray booth.
Last year I bought a 500mm fan off eBay and the cardboard filters in anticipation. I will only ever do WB stuff and generally stick to Morrells primer and top coat. Initially the plan is too recirculate the air, as taking it outside is problem.

So far it's a 3m wall with two sets of 900mm high filters as you see in The picture. There will be 1-1.2m wing walls attached, thinking of hinging theses so I can close the booth. Then a ceiling just under the beam which is 2.4m high with a light box may be.

Area located for it



Sussing it out! It's a very adhoc build



Lower section done and a test fit.



Box on the back for the fan to sit on top



End of play. Not bad with a fry included and fetching materials. Probably another day and it be sorted.



Very happy for your thoughts.

 

[davin]

Wish I had the space to do the same.
What kind of system are you using HVLP or compressor?

 

[mahomo59]

I'm on Hvlp. Morrells St1 turbine unit, I really like it.

 

[davin]

I just looked the Morrells sprayshop website, but it didn't have prices. It looks identical to this though, is it?

http://www.ebay.co.uk/itm/Q-Tech-HVLP-T ... 1139953362

Thanks

 

[mahomo59]

Yes identical

 

[MrYorke]

Have you done your research on recirculating the air?

 

[mahomo59]

Only what I can gather off other threads and the Internet. I incorporate some sort of exit baffles perhaps, bottom line is, I have no choice and anything better than what I have now!

 

[flanajb]

If you don't extract the air outside you will have to ensure your workshop is very clean, otherwise, any dust on the floor/walls will just get disturbed by the air from the back of the fan. They drag some serious volume through them. I vent mine outside just for this very reason.

 

[rafezetter]

If you don't extract the air outside you will have to ensure your workshop is very clean, otherwise, any dust on the floor/walls will just get disturbed by the air from the back of the fan. They drag some serious volume through them. I vent mine outside just for this very reason.

If would not be too difficult to add some baffles that reduces the speed and direction of the outflow, but that largely depends on the direction of the outtakes and intakes plus whether there is any filter meshing for the intakes.

Even with relatively quick drying water based I would not risk any dirty air getting into the booth, and would have several stages of filters for the intake, even if they are not directly joined to the fan but simply allow the fan to draw the required cfm's without it creating a pressure differential inside and outside the booth, because if you do, the moment you open the door - whoosh, all that bad unfiltered air will enter and ruin your lovely smoothly applied paint. This is why high end paint spray booths have the equivalent of an airlock.

An air recirculation system would not be too difficult to do, and would even allow for a multi step removable filter system with the right design, but would largely negate the use of oil based or other high VOC paint.

If you might wish to use VOC paints then I don't know how feasable this might be for a bigger fan output but I have read that for smaller hobby sized booths people have had success blowing the air through water via a rather nifty baffled sand trap.

essentially the air outfeed pipe end sits in a container of water that has sand in it, however to break up the bubbles and reduce the air just blowing the sand aside instead of filtering, there is a fine mesh on legs that sits halfway down the sand and the end of the pipe sits below that so the bubbles coming out are underneath the mesh which then further break up the larger bubbles not already broken up by the sand and from what I've read the majority of any contaminant is left in the water instead of coming out with the bubbles.

if you then put a good sized filter material where the air escapes, maybe combined with a charcoal layer, you've got almost clean air coming back into the workzone.

it's not a simple solution, but if you really cannot vent to the outside, it could be one way to do it without recirculating.

 

[rafezetter]

just as a caveat to below, I'm not an expert on booths, nor have I built one myself - yet, largely due to space - but I do have a tendency to spend many hours and do an awful lot of research before I understake any project as I absolutely abhore doing the same thing twice - and a home / small sized spray booth is something I have researched in detail for all the different permutations.

Looking at the pictures again can I assume that the hole in the top is for the fan? if so this design requires a rethink. All spray boths circulate airflow from the ground UP. This is to ensure that any airborne particles remain airborn and get little chance to settle on the painted surface. The airflow is also provided in such a way so that it's more like a gentle curtain instead of a directed flow straight from a fan, this reduces the possibility of creating circular flow in an enclosed space allowing the particles to travel in a downwards direction.

For recirculated booths the inner ceiling has filter mesh that catches and traps any errant dust fibres etc so they cannot fall onto the paintwork, and the booth airflow itself is kept running until the paint is at least 50% dry; many even have low lvl heaters to help bake off the solvents but so fast to cause paint failure.

here's a site with a good picture of what I mean - the grid mesh in the bottom is for the airflow coming in, and you can clearly see the filter mesh fabric in the roof.

http://www.novavertapaintbooths.com/paint-booths-2/

you also need to consider lighting, just 1 is not enough, for that sized booth you could use smaller halogen downlighters, but also have some in the walls so that you don't get any shadows on sides, and make sure they have wipable perspex covers for overspray.

and one last thing.. it doesn't look big enough if it's to be a stand inside unit.

 

[mahomo59]

Great! I'll do some research. Definitely big enough to stand up in, it's over 2.4m tall and Ross is standing up just fine.

 

[mahomo59]

Had a look at the site, very useful. I'm not going for an in closed room spray booth, just a wall. Here is picture of what I'm trying to imitate.



This is google image, but essentially the same one Morrells has at their branch in Bristol. The guy there, Chris is very helpful and has gave me what I believe to be good advice.

For the record, only WB will be used and I'm a big fan of Morrells WB primer and lacquer. I use this exclusively without exception, I've used at least 60L's since having the unit in March, I'm confident in my ability to get a good finish. Therefore wouldn't want to use acid or any of the other as I know little about it and the regulations must be pretty tight.

 

[studioman]

https://uk.pinterest.com/pin/373658100313554203/

Sometimes you can do things on the cheap. I don't do MUCH spraying, but I am conscious of dust and of my health, so I always use decent safety gear. I have to do my spraying at home in the yard which is dusty, so I now have a cheap second-hand four-sided garden gazebo and ground sheet which I pull out and erect whenever I need it. Simples.

 

[rafezetter]

Had a look at the site, very useful. I'm not going for an in closed room spray booth, just a wall. Here is picture of what I'm trying to imitate.



This is google image, but essentially the same one Morrells has at their branch in Bristol. The guy there, Chris is very helpful and has gave me what I believe to be good advice.

For the record, only WB will be used and I'm a big fan of Morrells WB primer and lacquer. I use this exclusively without exception, I've used at least 60L's since having the unit in March, I'm confident in my ability to get a good finish. Therefore wouldn't want to use acid or any of the other as I know little about it and the regulations must be pretty tight.

ahh ok I see - I was confused about the design because I couldn't see the outer cowling. One addition I would suggest is that once the items have been sprayed - assuming you are going to leave them inside the cowling - would be to fit a heavy canvas curtain to roll down after spraying to reduce the chances of errant particles while the paint dries.

 

[n0legs]

here's a site with a good picture of what I mean - the grid mesh in the bottom is for the airflow coming in, and you can clearly see the filter mesh fabric in the roof.

http://www.novavertapaintbooths.com/paint-booths-2/
.

Just to be clear, are you saying the air entering the spray booth is entering at the bottom/low level and extracting through the roof?


When painting in a spray booth the spray function is used, the burner/heater is on set to a temperature decided by the material being used and the item being painted. This spray function extracts the air out of the booth through the filtration panel/wall, then into the duct system via the exhaust fan (depending on the manufacture and design of the booth there may be a second set of filters in this ducting) then to the atmosphere.
When painting is finished the booth is switched to bake/stove. This function gets the burner producing higher heat (chosen to suit the purpose/demands of the material being used). Baffles are closed off so nothing is expelled through the chimney/vent stack. The heated air is then forced into the booth and extracted into a "closed loop" so to recirculate the heated air. This continues for the desired time until the paint/material is baked. Depending on the spray booths "clear out" time the air is recirculated a number of times per hour.
There may be some minor variations.

Water under a mesh floor systems were/are frowned upon in this country due to Legionnaires Disease concerns, although excellent at keeping the dust down. My brother in law had a spray booth of this type which had to be modified with the under floor tank drained and filled in with concrete. The insurance company decided this many years ago. Methods of water/air filtration I would not be sure of, dry filtration is the method of choice it seems using either the mesh type or card/paper filters.

Above is relevant for a proper "closed" spray booth with bake ability. A filtered "extraction wall" has other considerations in it's design and use.

I will add that there are some serious considerations to running a spray booth, some of which may get you noticed by the local authority.


:arrow: Mahomo59, looking good so far =D>

 

[mahomo59]

Here we go, I hope this clears up the type of booth/extraction wall I wanted to build. Pretty much the same as the one at Morrells in Bristol.

Wrongly or rightly I decided to angle the back as I needed more room behind the booth. All siliconed in around the edges to try and prevent air loss, framed it as well to conceal gaps.



The bulk of it done! Probably need a light in there, but it's not bad at all how it is.



The rear showing the slope. Put an extra skin of 9mm on this outer side as its the main traffic route.



From the rear looking towards booth and entrance into the shop.



In the booth looking out



Possibly found away to extract outside, up through the floor and out the eaves. We will see.

 

[scholar]

Looks interesting.

I wrote up my own dismountable spray booth build a while ago here home-spray-booth-lots-of-pictures-t41183.html. Since then it has had pretty good intermittent use.

A couple of points from my own experience that might be worth thinking about:

- I don't know what fan you are fitting. I fitted a variable speed controller that is very useful in my setup. I usually run the fan at about half speed - I guess you only need to ensure that there is a decent positive airflow towards the filter and if you have too much of a gale you will only pick up more dust from behind you.

- be prepared for quite a bit of paint dust to build up in and behind the pleated filter - that will only stop a certain amount (I guess the wettest spray is caught more easily). You will see a build up of very fine paint dust on the fan so that will be carrying some fine dust into the extraction airstream. I have fitted secondary box filters behind the main pleated filter and that makes a real difference.

- My spray booth is mobile, but where possible I do try to direct the airflow towards an open window. At present I use a cardboard tube wrapped around the extraction cowl, but really should find a longer length of flexible 500mm pipe.

- I don't know what accessories you use, but the ones I have made and find invaluable include:
- a drying rack. I made mine with some spur shelving brackets etc and to be adjustable in width. (I cannot show any pictures right now as the kit is in Cornwall and I am not).
- a couple of turntables made with scrap wood, but using ball-bearing turntable rings.
- a couple of knockdown spray tables made from scrap
- a couple of wheeled platforms that on their own or in combination with the knockdown table(s) and sometimes a turntable, makes moving and rotating workpieces of any size very easy.

As with you, I only spray WB - obviously this sort of setup is unsuitable for solvent based.

Look forward to seeing how it works in action.

Cheers

 

[scholar]

aah - I just noticed you have a really nice converted hospital bed frame (?).

Does the job of a few of my bits, But I would struggle to get that in the back of the car...!

Here is a random pic of my setup being used.



cheers

 

[stuffimade]

love the turn table, and a dedicated booth, great job!