Kiln venting

[Bill Kielb]

I like the extra hole Neil described above. It’s all based on area so I think two 1/4” holes are still less than one 3/8” hole and can always be plugged. That in-line duct fan is not a good pick in my view though so I think you will struggle to get it to work similarly to the commercial units. It needs to cool itself as well so you need to draw enough air for that to happen and still develop about 0.1” of suction to get some air out of the kiln. I think a stretch for that fan.

[moonzie]

Just to update anyone else who might find this helpful...

I ended up actually drilling 4 1/4" holes in the bottom of the kiln and 4 in my home-made plenum  box below the kiln. This provided enough ventilation that there was almost no fumes detectable during the firing, but a air-quality monitor we purchased recorded the air quality as being "poor" still (not sure what the PPM count was). It definitely was working much better than my original setup. The temperature of my exhaust vent pipe was around 135-140*f as it left the kiln and went up the wall towards the fan. Btw, that little crappy hydrocrunch fan did die after about 100 firings. Replaced it with a cheapy unit from Menards.

We've since purchased a small dedicated kiln shed 8'x12'. I'm in the process of getting it wired up. We also have a big ol Duncan we picked up that's 27"x29" for $100 that's in good shape. I'll be gutting it soon and converting to digital. I'll need to purchase a new exhaust motor (Dayton 1TDP7) and then recalibrate it all.

We've done just over 150 firings on our little E18S-3 quad kiln and it's just starting to slow down. Fast firings are taking about 6.5 hours where it used to be 4.5. New elements, TCs and open-ended TC tubes are waiting to be installed. Figure I'll swap it all out when the elements have breathed their last.

I've always had some difficulty dialing in the firings. We always pack it quite dense. It's either over or under per the witness cones. Hopefully the open-ended TC tubes will help with this.

Cheers!

[neilestrick]

7 hours ago, moonzie said:

Fast firings are taking about 6.5 hours where it used to be 4.5.

Most kilns can't really keep up with the fast firing schedule unless the elements are brand new. With a heavily packed kiln even less so. I would fire on the medium setting. With quad elements you should be able to get 200-300+ firings for bisque and cone 6.

7 hours ago, moonzie said:

I've always had some difficulty dialing in the firings. We always pack it quite dense. It's either over or under per the witness cones. Hopefully the open-ended TC tubes will help with this.

This is probably related to the fast firing schedule, too. The slower profile will go slower at the end and be more likely to  fire accurately.

 

7 hours ago, moonzie said:

Figure I'll swap it all out when the elements have breathed their last.

Elements should be replaced when the resistance is off by 10%. If you fire them till dead it will be a lot more difficult to get them out, and you'll be spending a lot more per firing as they have to work harder.