davidh4976

My local vendor (New Mexico Clay) is out of Custer Feldspar, but has plenty of Mahavir and G200 potash feldspars. I've used the Mahavir interchangeably with Custer.

Typically the bricks are good to cone 10+ as others have said. If you haven't seen it yet, take a look at what's called the "TDI downdraft conversion". I did this conversation and am pretty happy with it. There is even a book with good instructions on the conversion, and a FB group for discussion. I have fired to cone 10 in six hours. http://www.sebastianmarkblog.com/2018/

It all depends on the fit between your glaze and your clay. So, someone can recommend a glaze that works for their clay, but it may not work for your clay. If mixing your own glaze is not desirable, I suggest trying various other commercial clear glazes and just doing some testing. An effective way to test for crazing/fit is to take a test piece after it is glazed fired and alternately plunge it into boiling water and then ice water. Do this for 3-to-5 minutes in each bath and repeat the process 3 times. Dry the piece and then rub some India ink or dry erase marker on the piece and wipe off the excess. The ink will stay in the cracks making them easier to see, but you should also closely inspect, using a magnifying glass to see if there is any crazing. This test will accelerate any crazing that might otherwise only show up later (it's called delayed crazing). If you want to tackle this by mixing your own glaze, you should become familiar with the Stull chart and how recipes land within it's different areas predicting crazing, etc. You can find some good tutorials online for that. Then, look at some recipes and where they fall on the chart. If you use glazy.org and input a recipe there, the site will plot the recipe on a Stull chart for you.

It's an old Gare 1027 that has been converted to a digital controller. It had been working well except we were starting to get really uneven firings and the element resistances were starting to vary greatly from element to element. I replaced the elements and ran a quick "paper test" that showed all elements were firing. Then I ran the oxidation firing (cone 04 with 1.5 hour hold) with no problem. Then I replaced the plug because it was showing some thermal stress. Started a cone 6 test firing (empty except for shelves, posts, cones). The circuit breaker tripped at some point. I did a brief look at the new plug and the elements and everything looks OK at a quick glance. It turned back on (without firing) without problem. Then, I just sighed and went home! I'm going to start troubleshooting this morning. I'll start by opening the control box and checking for obvious shorts. The circuit breaker was reused from the time the building had been a machine shop, so there is a possibility that the circuit breaker is going bad. Any thoughts are appreciated. UPDATE: no signs of any problem with the kiln, its wiring, or its plug. But, I checked the circuit breaker and found that the electrician we hired to put in a 60 amp circuit for the 45 amp kiln only installed a 50 amp breaker (when we moved the kiln six months ago)! It looks like he reused an existing but unused 50 amp breaker. Moral: double check what your electrician installs! My current theory is that the old elements were drawing a little less power than the new elements, and now the new elements are drawing just enough to cause the breaker to trip. Generally, breakers don't like more than 80% of their rated amperage for prolonged periods of time. I checked the circuit wires and fortunately, the wires are correct for 60 amps and it's just the breaker that needs replacement. I have a call in to the electrician. In the meantime, I checked everywhere in town and no one carries the breaker type that we need, which is probably why the electrician did not install the 60 amp in the first place. We went ahead and ordered a replacement breaker. To be continued...

Make sure you install wires that are suitable for 60 amp. If you want to argue with the inspector, and assuming you are in the US, here is the applicable section from the National Electrical code. 210.19(A)(1) General. Branch-circuit conductors shall have an ampacity not less than the maximum load to be served. Conductors shall be sized to carry not less than the larger of 210.19(A)(1)(a) or (b). (a) Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit conductor size shall have an allowable ampacity not less than the noncontinuous load plus 25 percent of the continuous load.

[I edited out my mistaken reply; don't know how to simply delete it.]

No, that's different from John's Noxema (in John Britt's "The Complete Guide to Midrange Glazes). But, now that I put John's Noxema into Insight, it too has a high expansion and I would expect crazing on stoneware.

Min, thanks for the info! It's good to see someone else's work. Yes, I use the Insight tool and do 200mg test batches. I think I'll try your conversion with the calcined EPK in addition to John’s Noxema. I don't mind testing more than one version at a time and then selecting the one I like best. And, I always do tests that include crazing tests for our clays.

I'm using Frit 3195 and it's breaking. I'll try John’s Noxema”. Thanks for the tip! I saw that in Britt's book, but it's so hard to tell if it's breaking by just looking at the photos. Same challenge with the glazes on glazy.org.

I started working up some blue glazes by starting with a some good gloss clear glaze recipes I've used before and adding 1.5% cobalt carbonate. On the batches I've run, the fired glaze goes clear over edges. It looks great if that's what you want, but I'm looking for a blue glaze that stays blue even over edges/texture. I also want to avoid Gerstley Borate, Neph Sy, and Talc. GB because of end-of-production. Neph Sy because it somewhat contributes to hard panning. Talc because of recent quality. For cone 6 stoneware. Any ideas or suggestions?

It turns out that Evenheat does sell replacement bricks, at least for the Gare 2327 that I asked them about. They just don't list the bricks on their website.

I need to replace some firebrick in a Gare 2327 and haven't been able to find any replacements online (including at the Evenheat web site). What's the chances of being able to buy Skutt or Paragon bricks and having them fit correctly? The Gare is 10-sided, uses 2 1/2 inch thick brick and I only need bricks with two straight element channels. (I'm really not looking forward to this repair because the Gare 2327 has a one piece outer casing. It doesn't break down into multiple layers. I have to replace the elements, too, so I will be doing the elements and the bricks at the same time.)

This was also posted on Reddit and there you can see there that data plate says 3 wire.