The next step after the workbench was the paint booth. It's not something I will use frequently however I have more than enough room in my garage for it and it's very useful when I do use it, not to mention preventing any overspray on everything else in the garage. The booth at my old house was sized 2m x 1.5m and served me well so I decided to retain that size. The ventilation of the old booth however was woefully limited so this time I did some proper calcs to the inlet/outlet filter sizes and fan size I would use.
From my (internet) research, the sizing of fans/filters are all based around calcs of air velocity of 100CFM. If the air velocity is too high you get overspray due to turbulence within the booth. Too low and the paint fumes etc do not get sufficiently extracted. The other design aspect was whether to have a downdraft or cross draft booth - that was a simple choice since I was not going to make a complex manifold under the floor of the booth, so cross flow it was. I just had to ensure that there was air flow across the whole width of the booth.
I started making the exhaust manifolds. Due to an error when the cement was poured, the slab was ~20mm too short which resulted in a gap between the slab and wall sheets. I took advantage of this and designed it to that the outflow would be through this gap. The air would flow through filters across the width of the booth, via the first manifold, then through a fan, then into the floor-mounted manifold. The area of the gap outside this sealed box is the same area as the 200mm fan and duct, as to prevent and restriction.
The booth was then cladd with 3mm MDF inside & out (second hand cover sheets from a cabinet maker) and the roof was 6mm braceboard so I can store timber, MDF sheets, random things on top. The exterior was painted the same colour as the workbench.
Here is the cladded interior - you can see the 200mm duct to the fan in the middle of the manifold. I am yet to build a bench inside and the outlet filters will sit in the openings. The filter media was sourced from an air conditioner wholesaler, installed in standard flyscreen frames.
On the exterior, I have some compressed air fittings. The compressor will be located inside the booth with an flexible air line running from the compressor to the RHS of these fittings. Air will travel through the filter/regulator and then either travel down the LHS of the fittings back into the pant booth (for paint gun), or out to the air lines that run around the perimeter of the entire workshop. The switch next to the door will be for turning on the interior light, fan & compressor without having to enter the booth. I also have a small ball valve (red handle) in these fittings to purge the system of air when I've turned the compressor off.
From my (internet) research, the sizing of fans/filters are all based around calcs of air velocity of 100CFM. If the air velocity is too high you get overspray due to turbulence within the booth. Too low and the paint fumes etc do not get sufficiently extracted. The other design aspect was whether to have a downdraft or cross draft booth - that was a simple choice since I was not going to make a complex manifold under the floor of the booth, so cross flow it was. I just had to ensure that there was air flow across the whole width of the booth.
I started making the exhaust manifolds. Due to an error when the cement was poured, the slab was ~20mm too short which resulted in a gap between the slab and wall sheets. I took advantage of this and designed it to that the outflow would be through this gap. The air would flow through filters across the width of the booth, via the first manifold, then through a fan, then into the floor-mounted manifold. The area of the gap outside this sealed box is the same area as the 200mm fan and duct, as to prevent and restriction.
The booth was then cladd with 3mm MDF inside & out (second hand cover sheets from a cabinet maker) and the roof was 6mm braceboard so I can store timber, MDF sheets, random things on top. The exterior was painted the same colour as the workbench.
On the exterior, I have some compressed air fittings. The compressor will be located inside the booth with an flexible air line running from the compressor to the RHS of these fittings. Air will travel through the filter/regulator and then either travel down the LHS of the fittings back into the pant booth (for paint gun), or out to the air lines that run around the perimeter of the entire workshop. The switch next to the door will be for turning on the interior light, fan & compressor without having to enter the booth. I also have a small ball valve (red handle) in these fittings to purge the system of air when I've turned the compressor off.
The fan I used was a Blauberg Turbo 200 - a 200mm diameter axial fan capable of 1080m3/h (635CFM). If for some reason the flow is too high, it has a Low mode at 805m3/h (474CFM).
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