I get this question so often I thought I would post my reply here:
AGG Member, Barbara Atkinson (Williams)wrote:
I am looking to get a kiln and I am interested in a Hoaf. I have talked to Quint in Tx, and it seems that it runs around $5,000 for the 40X40. Before I make the commitment I thought I would get your advice. Whatever kiln I get it will have to be in my basement. I thought the Hoaf would be safer as the firing time is so short and I would be there to monitor it. I'll have to figure the venting situation. Of course the best place to vent would be facing my next door neighbor who is 3 ft. away and very particular, so I better think of another place. Is venting for a Hoaf more problematic than others? Anyway, do you have any strong opinions/suggestions?
The Hoaf is great…for painting. If you plan to ultimately do fusing as well, you will be better off with an electric kiln. I like the Paragon Pearl 22 and Denver Glass Machinery KL27 (both around $2500). The Hoaf is not really rated to go up to full fusing temp (>1500F) I never take mine above 1350F.
Technically any kiln should be vented. The organic materials in shelf paper or the medium you mix the paint with (lavender, clove, turp etc) can get pretty stinky if you fire indoors. That said I do have a small electric kiln in my basement that I fire – very sporadically – and I don’t vent it to the outside. Whatever toxins are created are dispersing in a large enough volume of air to not be an immediate problem. If there is residual build-up of materials it will take a very long time to reach a hazardous level considering how infrequently I fire this basement kiln. (Although I am thinking of getting a canary)
However, when I fire my Hoaf at home I put it in the garage and leave the door open for the 10 minutes of the cycle.
This issue of venting comes up all the time. It doesn’t need to be more complicated or obtrusive that the vent for your clothes dryer. I just found this inexpensive system which claims can be used on any electric kiln but I don’t think it would address the CO2 from a gas kiln: http://www.dickblick.com/products/skutt-envirovent-kiln-ventilation-system/?wmcp=google&wmcid=products&wmckw=30178-1001
Venting a kiln shouldn’t affect your neighbor unless she’s homeless and sleeping by the vent for warmth!
The hidden expense with electric kilns is calling in the electrician to add the breaker and receptacle. You may also need to upgrade your residential service if you don’t have 220 or 240 volts available. Discuss this first with the kiln manufacturer.
Let me know what you choose.
not a large enough capture area for the fumes, and the air movement in cfm is not enough to thorougly remove obnoxious odor before it enters the room. I have a large hood over my kilns that draws everything away, but still exits to the atmosphere thru the wall. Not inexpensive, but neither is the skutt. Didn't Orton have a vent system similar to the SKutt?
I picked up an industrial strength fan that was used in a barn for my kiln room. It is so strong it sucks the door shut with a bang. This definately keeps fumes from entering the rest of the building. The fan blades are about 12" in diameter but it has a strong motor.
Late in this discussion, but anything even as small as 20cfm that creates a negative pressure will pull the noxious fumes up and out. Even the fans we use firefighting can charge and entire three story building. Again, all we are trying to do is create a small amount of pressure within the building and then smoke will move. For our kilns in the studio we use a bathroom fan; Divide the volume of your room in feet by 7.5. The result is the CFM, or cubic feet per minute rating required for your fan. The CFM represents the airflow required to completely exchange the air in your 8 times in one hour. So if you have a room that is 12 feet long, 15 feet wide and 10 feet tall, then it has a volume of 1800 cubic feet (12 x 15 x 10) and a CFM of 240 (1800/7.5). Hope that helps a little.....