Built a diy spray booth...leave comments please and thank you!!

[kaho]

Hi. I have just finished building a spray booth. Its driven by 4 92cm case fans, which are powered by a computer power supply. The body is made from cardboard, with a vinyl duct in the back sending fumes out the window. It took me 4 days to build.

I have some pictures too:



The overview of the booth. The actual booth is made of cardboard off a television box. The fans are inside the mitsubishi box (only the top one, the bottom one is there to raise up the entire machine, so that the exhaust won't need to climb upwards to go out the window. The power supply is under them. The booth and the mitsubishi box is not fixed together, I just put it on top so I could change filters regularly.



Three fans are lined up near the outside edge of the booth(sides 37cfm and middle 28cfm), with toilet paper temporarily used as a filter. I put the fans there because they wont need to fight gravity to pull the paint fumes through them, and near outside edge to keep the other particles from being pulled through the model when i paint. It just took the filters like 2 seconds to change colors.



Behind the mitsubishi box there is the forth fan (my biggest fan that does 119 cfm)pulling the fumes from inside the mitsubishi box out into the duct, which goes outside the window. The problem I found is that I can feel wind leaking where the duct connects to the box. I didn't use any kind of adhesive, just tucked the duct into the rim of the exhaust opening hole. Anyone have any idea on how to seal up the duct?


I want to see what you guys have to say about this spray booth. When i spray I could smell the fumes for the first few seconds, and the smell would subside fairly quickly, although its not instantly, is that normal? When I spray without the fans turned on, I could see the paint dust immediately build up on the floor of the booth, which means the booth was at least doing a good job pulling paint dust onto the "filters"(good news). Can you guys tell me what i could do to overall improve this booth? Like what filters could I use instead of toilet paper...how to fix the exhaust duct properly...are the fans put onto a good location..etc. Feel free to post comments and suggestions!

Thanks!

[SteveK2003]

Looks good, but you could maybe improve a couple areas:

- Cardboard can lead to dust in the air and paint, especially those trimmed edges, so you might want to build one of out plastic at some point. I'm moving soon and my plan is to make a skeleton frame out of wood or metal, and make the walls out of sheets of clear polycarbonate to let light in.

- Drape some plastic sheet over the opening to keep dust from settling in the box when it's not in use.

- I don't know about the exact risks, but when you have an electric motor in the air stream, you do risk a fire/explosion unless it's an explosion proof fan.

- Testors sells the filter sheets for their spray booth separately. From what I have seen they use more than just the sheets for filtering, but those should be better than anything made from paper (Which would also contribute to any dust in the box).

- You could try some adhesive-backed foam wrapped around the hose coupling to seal it up better, if you want to remove it (Wrap the foam around the coupling and squeeze the hose around it). If it will be in place for a while, regular silicone sealant will work.

[ImolaEK]

Very creative

[SchuberT]

Coffee filters make very good filters (duh). We use them for our DIY spraybooth.

[Sticky Fingers]

Put some duct tape over those cardboard seams to prevent it falling apart

[kaho]

Ok one night I was trying out spray painting inside the spray booth. Turns out whenever I spray the overspray(at least the fumes) were coming straight towards my face! It was visible when a light was shine through the booth opening. Apparently the fumes were first directed out of the booth, and then they raised slightly, and became invisible due to the fumes being dissipated. However, the instant decrease in fume smells shows that the fumes were in fact being sucked into the fans.

From that I could tell the air near the fans are being rotated around, outwards at the bottom of booth, then upwards at the top of the opening of the booth, then the air is being pulled into the booth and down the fans.

(I hope whatever that I just said makes sense to most of you here. Its hard to catch the movement of air within a picture)

Could the arrangement of my fans cause the air to circulate improperly? From the experiences of you guys, how would you rearrange the locations of the fans to prevent the paint fumes from blowing back out the booth?

Thank you in advance.


P.S. I already taped the exhaust duct onto the fan box, and I am going to keep the booth being made entirely out of cardboard for now. Thanks for the suggestions from the previous people

[008]

Two main reason fumes are getting blown back are a) your fans are not strong enough and b) the box is too shallow. The pressure from the gun is blowing the paint against the back of the box and right back into your face. Try extending the opening or making the box deeper so that the paint has some room to slow down. A small lip on the bottom of the opening might help, too.

I would also suggest something to seal the actual window and prevent fumes from blowing back in. You could use a wall outlet adapter for the duct and mount it on a sheet of plywood that you can wedge into the window opening. Bolt some cabinet handles on it so you can install/remove it easily.

Booth or not, you're still using a respirator I hope. There are many bad things in paint that you can't smell.

[PlumbedandWired]

For filter material, I go to my local auto body sprayers and ask them for offcuts of the filter material that they use for their full size spray booth.

If you offer and are prepared to pay them for the stuff, 9 times out of 10 they'll just give it to you for free.