Airbrushing and dust contamination

[David Waite]

Hi Michael
The gap at the top and bottom of the window even the sides that is caused by the extractor air pipe could be blocked easily by using soft black rubber pipe insulation the type that is used for the refrigerant lines on Air conditioning systems it is made in various diameters and wall thickness, the thinner wall thickness will flatten more easily and it is cheap to buy usually comes in 2 meter lengths and easily cut with a sharp knife this could simply be squashed into the gaps and if the correct size is selected the friction hinges on your Velux windows should hold the window position with no problem my Velux windows are GGL4 type and their friction hinges could certainly do it, in any case if you use the push lock on the window there wouldn’t be a problem.
David.

 

[John_B]

It's not perfect and there is room for improvement, but as a base test I can live with the moderate levels for short duration's.

Were you wearing a mask?

It would be interesting to know what the readings would have been with the window shut, and without the spray booth fan running, to see how effective/ineffective the spray booths are.

 

[mickoo]

Were you wearing a mask?

It would be interesting to know what the readings would have been with the window shut, and without the spray booth fan running, to see how effective/ineffective the spray booths are.

Afraid not, I rarely do unless spraying etched thinner, I know I should and I do have one but it's more for particulates (relative here) than TVOC's which etched thinners are rich in. Of the two, personally TVOC's are my bigger concern.

I can do a quick test later with the window shut but know it'll go through the roof, I did a quick spray (3 mins) last night under just such conditions and I could see the mist hanging in the air at the end of the workshop, I didn't need a meter to know levels were high.

The booth I have is not the most effective, but it's not totally useless, another good place to test is directly behind the booth where the pipework exits, that'll help reveal if there are any leakages, I'm sure they are.

I'm also confident Micheals (org OP) long thin flat tip to his hose is creating back pressure and not exhausting the gasses freely, these booth fans are not big air movers and any impediment to the flow of air is going to stunt it's dissipation.

If I do small squirts (3-5 seconds) on small pieces then levels stay low but longer spray patterns for large areas (5-10 seconds) can overwhelm the fan and you can see the spray coming back at you as the fan cannot clear it.

Some units now come with dual fans which would help that, removing the filter might help as well but you're fan blades are going to get covered in paint dust quickly and thus be less efficient.

I do have a fixed vent I need to install so that I don't need to keep opening the window, but right now I'm in the throes of building a layout so not sure where the booth will end up and thus the best place to punch a hole in the wall for the vent.

 

[John_B]

I'm also confident Micheals (org OP) long thin flat tip to his hose is creating back pressure and not exhausting the gasses freely, these booth fans are not big air movers and any impediment to the flow of air is going to stunt it's dissipation.

The one I've ordered has the same tip to the hose. It shouldn't be a problem to change it, as I need vents for my resin 3D printers and diode laser to leave the house in the same place.

It looks like mine has one fan:
"Effective Ventilation Fan:
Powerful pumping capacity to quickly extract the toxic gas. Withdraw 4 cubic meters of air per minute. Reduces users inhalation of paint fumes. "

Maybe I can add more fans!

It's this one: https://www.amazon.co.uk/dp/B09JZCS1M7

 

[mickoo]

That is a single fan unit and adding a second isn't easy, you'd be better off just buying a twin fan unit to begin with to be honest.

I did a quick test yesterday for fan effectiveness and with doors and windows shut, with the sensor in the same place it was sitting around 90 but you could see the mist at the far end where the hose was out letting, in time it would have migrated to the end I was working in.

Then I decided to test directly behind the fan to see if there were any leaks in the pipework, still sat around 90.

As a final test I went to the dirty end of the workshop and it was around 300 and coming out of the hose was 590.

So if the hose is outside like it should be then you're shifting highly toxic 500-600 particle levels outside and maintaining a moderate risk on 50-100 locally at the booth, I'd say for a hobby unit that's reasonably effective. The important part is making sure there are no leaks on the high pressure side of the fan and hose.

It did show that I need to be less lazy and drop the hose out of the window every time I spray....or get the fixed vent sorted and a final position for the booth.

Having said that, I only spray for 5-10 minutes three/four times a week, if I were doing it longer and more often then I'd try to get the levels down a little more, a wall mounted vent fan (something like a larger shower fan unit) above the spray booth area would be a good consideration, perhaps even a hood over the area to capture any spray that kicks back out of the booth at higher pressures....or a twin fan unit.

 

[Yorkshire Dave]

Rather than extra fans perhaps consider a cooker hood extraction unit assembly permanently mounted over the spraying area (some are cheaper than the booths sold for modelling use). Could be possible in permanent modelling areas such as sheds and workshops but would have to check the specs for the extraction volume/rate.

To enclose it further you can always add drop down curtains to the side to create the spray booth - thereby eliminating a smaller portable spray booth.

During hot weather the extractor can be run to draw cooler air into the shed/workshop.

 

[DavidB]

I know this thread is more about airbrush spray booths, but dust is in the title (and air) which can be a nuisance when it gets in to contact with wet paint. When I have cleaned a model, I put it under cover, bringing it out only to paint. I use a seed tray cover (without the tray), the type used as a propagator.