fazer

​For those folks spraying dope/lacquer indoors- what is a safe way of exhausting fumes and overspray to the outdoors.

I am going to build a temporary spray booth with an opening on one side with a furnace filter.On the opposite side of the booth
a fan with another furnace filter to the outdoors near a window.

I am going to be spraying big 1/3 scale airplanes.

My main concern is the fan. Explosion proof fans are expensive. Is there a way to bypass this expense but still be safe without blowing-up
the place.

Any suggestions would be appreciated.

TomCrump

It's not just fans that should be explosion proof. When I worked in a paint factory, the lights, light switches, compressors, fork lifts, hand tools, everything had to be explosion proof.

In a more practical world, ventilation is your friend. I paint in my garage. I open up every door and window. The down side is that it is really only feasable to paint in warmer weather.

The only paints that I find safe to spray in an enclosed space are waterborne products, like those from Warbird Colors and Nelsons Hobbies. I've used your furnace filter method with them. It works fairly well.

jollyroger

My Feedback: (6)

HI Tom! Hope your having a merry Christmas. See ya around sometime.

TomCrump

Maybe in the Spring. That is, if the snow ever melts.

acdii

Belt driven fan, with the motor outside of the booth and air flow. Thats about the only way you will be able to do it without the expense of explosion proof fans.

What I did years back is found an old furnace that still had a working blower. Mounted the motor outside the cabinet and used a longer belt, put a longer shaft on the blower and ran it through to the outside with a seal on the cabinet and sealed it all up. Then mounted my filters pre and post blower and vented it outside. The shaft was just a 3/4" barstock with flats on both ends and used a 3/4" conduit connector to tie it to the blower(also had a bearing unit I got from Farm & Fleet on the cabinet). Cost me under $20 for the whole setup.

Leroy Gardner

frazer if you have a couple of gas furnace repair services in your area go and tell them you are looking for a used fan and mount off of a hanging gas heater, they are used alot in old and new shops, the heat exchanger gets burned out but the fan is still good and they are explosion proof. If your lucky enough to find one they might just give it to you. Grainger has new ones and I don't think they are too expensive, worth a look. I put up a temporary spray booth in my shop that works well and I can run the explosion proof furnace I have while I spray, crack a window and turn on the exhaust fan and have at it. I usually spray urethane paints and wear the proper resperator and you need to do the same thing, all the paints you mentioned are the nasty ones so keep that in mind.

I just hang 3.5 mill plastic stapled to ceiling and walls and leave an opening at the top of the front to allow air to sweep through the enclosure, use paint cans and buckets to hold the walls on the floor, leave a flap to open to get stuff in and out. I also have shutters on outside wall where the fan is mounted, it's only 20" fan and will create a vacume in the whole shop.

Leroy

malitape

My Feedback: (213)

Leroy,
exactly which respirator is required for these materials? Brand name? Tanx

Top_Gunn

My Feedback: (6)

I spray dope with an airbrush, held maybe six inches from the surface, at about 20 psi. There is no overspray. In fact, I do this on my workbench and don't need to cover anything nearby to keep it clean.

acdii

What size tip and brand AB are you using? I tried it with my Badger using the heavy tip, seemed to use more dope than I did with the brush for less coverage.

TomCrump

If your paint is not properly thinned, you will use more paint.

Top_Gunn

My Feedback: (6)

I use a Paasche single-action airbrush with the heaviest tip. Dope, even thinned quite a bit, seems thicker than the lacquers I mostly use for plastic models. With those, I usually use a double-action airbrush, although the Paasche works well with Alclad paints.

acdii

The fabric I used had a more open weave to it than Koverall does, so that might have been the reason I needed to use so much. My Cub will be covered in Koverall and I got a pint of white and a half pint each red and blue for it along with a pint of clear and a pint of Stix-It, so if I run out it my own danged fault!