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#100192 Cooking Pizza In A Pottery Kiln, Toxicity ?

Posted by neilestrick on 19 January 2016 - 09:36 PM

So just so we're clear, I don't have any hesitation in saying the OP is having a laugh at our expense.  Mark Dally, the OP--Crunchypop, is a potter with a lot of experience (like, graduated from art school with an MA in ceramic design the year before I was born kind of experience).  He knows better than this.  He fires lustres and brightly coloured wares all the time.  From what I've seen of him on social media, he's got a bit of an impish sense of humour, too.


At least, I hope for the sake of his health that he knows better after 34 years plus of working with ceramics....



If it is a joke, it's irresponsible of him to post something like that on the 'net, where folks who don't have his level of experience might think it's okay.

#100185 Cooking Pizza In A Pottery Kiln, Toxicity ?

Posted by neilestrick on 19 January 2016 - 08:02 PM

Really bad idea. It's not just the dust, but the fumes from all the stuff that's been burning out of your clay and glazes, including metals. When the kiln heats up those things come out and can get into your food. Would you eat food off your glazing table? No. So don't eat food from your kiln either. Food and industrial processes don't go together.

#99999 Reliable Cone 6 Temmoku Glaze Recipe Oxidation

Posted by neilestrick on 17 January 2016 - 05:34 PM

Manual kiln I have lol...


Our plans as of now are to get a smaller kiln to test with and then get into making our own glazes... Our bigger kiln will be a bisque kiln or maybe convert it to gas... we just got a price hike from our electric company... UGH


If you run tests in a small kiln but fire work in a larger kiln, you will not get the same results. Little test kilns cool really fast. IF you plan to go that route, I highly recommend getting a digital controller on both kilns so you can do the same cooling cycle on both kilns. At the very least you'll want a digital controller to control the cooling on the small kiln to mimic the cooling cycle in the large kiln, even if you don't have a controller on the large one.

#99871 Is A Square Cross Draft Kiln More Efficient?

Posted by neilestrick on 16 January 2016 - 11:45 AM

I would not use the soft brick stacked on their sides. They won't stay put. When using both types of brick you need to run a course that ties them together every 5-7 rows. I think you can do a 4.5" soft brick inner row with a 4" hard brick outer row and be fine. You're only half an inch short of normal there. Fiber is a mess. Avoid it if you can.


I would go with Marcia's design if you need both burners and want to use a single shelf. If you don't have enough bricks for that, go with bringing the burners in on the same side, opposite the flue, along the long side of the shelf.

#99775 Good Wood Fired Clay Over The Counter?

Posted by neilestrick on 15 January 2016 - 01:08 PM

sorry- which troy body do they have? I think they have 437 and 621 . 


He said the porcelain one, which means the 437.

#99768 Good Wood Fired Clay Over The Counter?

Posted by neilestrick on 15 January 2016 - 12:33 PM

Rebekah- I was in Evanston today and they said they stock the 508 woodfire body, and usually have a couple boxes of the Troy woodfire, too. If you decid you want some let me know and I can get it to my shop to save you some drive time.

#99697 """need Help Quickly"""

Posted by neilestrick on 14 January 2016 - 09:56 PM

Yup, you did it right. It's only the last 200 degrees that really matter.

#99695 Is A Square Cross Draft Kiln More Efficient?

Posted by neilestrick on 14 January 2016 - 09:47 PM

So, a layout like this image- burners on left, long shelf, exit flue on right? Would do it the other way- turn the shelf so the burners are coming in along the long side of the shelf, leave 9" or more for firebox and bag wall.


Attached File  Jed-Kiln.jpg   12.33KB   0 downloads

#99436 How Can I Convert A Large 3 Phase Kiln To Single Phase?

Posted by neilestrick on 12 January 2016 - 08:56 PM

They demand lower operating costs and pay for the power grid lines to bring in 3 phase. 



3 phase kilns do not cost any less to operate. Firing costs will be the same regardless of phase. Watts are what heat kilns, not amps, and watts are what you pay for. Regardless of the amperage, the watts will be the same.

#99434 How Can I Convert A Large 3 Phase Kiln To Single Phase?

Posted by neilestrick on 12 January 2016 - 08:52 PM

If it's pulling 37.5 at 3 phase, it will pull about 65 amps at single phase, which will require an 80 amp breaker. Depending on how it's built and local codes, that could mean a major rewiring, including fused branches inside the control box, bigger relays, etc. You'll need to check with the manufacturer. They will be able to tell you what's needed.

#99428 How Does A Gas Kiln Controller Work?

Posted by neilestrick on 12 January 2016 - 08:10 PM

If you're doing the damper and air manually anyway, what's the point of spending all that money on automating the gas flow?

#99067 Firing An Electric Kiln In A Garage....

Posted by neilestrick on 08 January 2016 - 10:48 AM

Do not wrap anything around your kiln! If you need to slow down the cooling rate, then do a controlled cooling in the firing program.

#99039 Raw Materials

Posted by neilestrick on 07 January 2016 - 10:28 PM

The unity formula is the molecular ratio of the elements in a particular glaze. Those elements are supplied by the raw materials in the glaze recipe. The unity formula allows us to compare glazes more accurately than looking at a recipe, since a glaze with 15% calcium carbonate by weight in the recipe isn't necessarily 15% calcium in it's final fired state. Also, many materials supply more than one element, so the unity formula shows that. The unity formula also allows us to substitute materials, since there are numerous materials that can supply each element. It also allows us to make specific changes to the glaze that can't easily be made by changing the raw materials in the recipe.


Example: I have this glaze that I love, and I use it all the time. The recipe contains materials that are all mined here in the USA. If I move to Australia, I won't have access to those specific raw materials any more, but I will have access to other materials that can supply the necessary elements to make that glaze. So I can take my recipe and convert it to the unity formula, then convert it to a new recipe using the materials I have available. The recipe is different, but the molecular makeup of the glaze is the same.


Another example: I need to increase the alumina content in a glaze. There's no alumina in the recipe- it's being supplied by the feldspar and the kaolin. If I increase the feldspar, it will also increase the potassium and sodium and silica. If I increase the kaolin, it will also increase the silica. So I have to go into the unity formula, increase the alumina in the formula, then convert it back to a recipe.

#98851 Cones And Temperatures

Posted by neilestrick on 05 January 2016 - 04:30 PM

The Orton datasheet says "as a general rule, a 1 to 2 hour soak is sufficient to deform the next higher cone number." so I was expecting 20 minutes to only make a small difference, perhaps only 1/2 a cone.


I've done a number of soaking tests in my electric kilns, and combined with that experience and everything I hear about here on the forum, the degree to which soaking affects cones seems to be very inconsistent. I used to fire my big electric to cone 6, then soak for 40 minutes to achieve cone 8. Much shorter than the 1-2 hours you mention from the Orton sheet. When I started firing cone 6, I tried a similar soak to go from cone 4 to 6. It took 80 minutes, and the glazes did not respond well at all. Many were under-fired. And every couple of weeks here on the forum we hear about someone's kiln that accidentally soaked for several hours, with surprisingly few poor results. A couple of pots stick to the shelves, but by and large things seem to survive. Soaking is a strange thing, and while short soaks (under 20 minutes) seem to have noticeable affects on glaze melt, as the soaks get longer the effects seem to diminish. It seems that at some point you need higher heat, not just heat work.


Just my thoughts, which may or may not be at all accurate.

#98505 Repairing Old Olympic Kiln

Posted by neilestrick on 01 January 2016 - 10:35 AM

I would do away with the box plugs and just hard wire the sections together with slip-on terminal connections. Those plugs are a weak point in the system, and will fry out in the (near) future. Replace all the elements, and any bricks that are broken.