Potters & Sculptors - Making Rock from Mud
When I put my electric kiln in the basement, discovered that it put out enough fumes to give me a headache when firing. So a kiln vent was in order. I decided the commercial units were too expensive for what they are made from so I opted to build my own. The little 4" duct fan I purchased didn't develop enough suction to reverse the bottom to top heat flow in my kiln.
So I got a powerful Vortek 4" fan that has excess drawing power.
That could have been the end of the story, but when I saw what Steven Hill was doing by spraying glazes, I knew I had to have a spray booth. Again being the cheapskate that I am, I was horrified by the prices of spray booths. It occurred to me that if my booth had a small enough opening, I might be able to use my kiln vent fan to vent the spray booth. I was thinking of building the box out of wood, but decided to look for alternatives. Steven's booth was built from a fiberglas shower stall. Off I went to Home Depot in search of the perfect spray booth. I ended up getting the biggest Rubbermaid plastic storage box I could find.
I cut out one end of it and cut a 4" hole in the other end, and added a 4" duct adaptor. I just sit the thing upside down on top of my kiln an connect it to my vent and it makes a serviceable spray booth. I buy cheap furnace filters, cut them in half and layer 3 of them in front of the exhaust to trap as much glaze overspray as possible.
My setup is a little small but quite useable. It captures most of the overspray, except when spraying a hollow form like the inside of a bowl that sends the spray back at me with enough velocity to overcome the fan's draw, but I wear a respirator when spraying, so it's not that big a problem. I've done three spraying sessions and am pretty happy with my setup. -George Lewter-
Update Feb. 8, 2112
What I have allows me to spray glazes and contain almost all of the overspray. I go through a fair amount of furnace filters and the glaze in the filters is wasted.
800-1,000 cfm is the recommended air movement for spray booths. Mine is only 160 cfm, serviceable, but not a strong intake - go higher if possible with 6-8" vent piping. Its what I had already in use for my kiln vent. More air movement is better.
I plan to replace the plastic box with the tub from an old dishwasher for better size and easier cleaning. The bottom half of a broken 36" fiberglass shower is also a good choice. Plumbing supply places frequently have them that have been damaged in shipment. The air outlet will be at the top. It will also work better if I get around to a water bath system which would spray water down the walls and into a reservoir with a recirculating pump. The glaze would settle to the bottom and clearer water nearer the top would be drawn up to again for spraying down the walls. This would capture most overspray and keep the used glaze for recycling into scrap glaze.