Bill Kielb

Commercial glazes, err, some commercial glazes may contain less expensive ingredients and/or behave poorly.
Less behaved glazes may: settle quickly, crawl, craze, pinhole ...have washed out color (especially where expensive colorants are involved) ... etc.
When looking for recipes, starting out*, a few ideas (which I'd found here, in this Forum, and a few other places**) were helpful:
   from a reputable source;
   with helpful notes on application, durability, and heavy metal leach testing results;
   with pictures!
I just picked several recipes, made a materials list, and went shopping***!
From there, learned, err, learning from successes, failures/mistakes, and more reading.
...and thanks to several Forum regulars for insight and assistance.
 
*Coming up on six years ago, how time flies
**Digitalfire.com, a trove of information; the glaze recipe book at local JC ceramic lab (we were using the glazes - direct experience!); Petersen's  book The Craft and Art of Clay; Van Gilder's book Wheel-Thrown Pottery; and several other books, magazines, and web pages. Oh, web pages! ...Hesselberth's website can still be found, FrogPondPottery, Tested Glazes | Frog Pond Pottery (archive.org) 
Lakeside Pottery also has glazes sub-pages with pictures and notes...
***took the pickup truck, packed the load up against the front of the bed and tied it down tight, some twelve hundred pounds of clays and glaze materials...

Just to add, much of this will end up to be surface observation. Does the glaze melt fully and for instance does it appear uniform and thick enough for 100% coverage. Sort of subjective but also can be obvious for glazes that are applied too thin and end up rough to the touch. Glazes not fully melted that should be gloss but are more matte.
Observing the finished product often reveals whether the application thickness was appropriate for the glaze as well as whether the firing schedule was appropriate.
Test tiles created while varying coverage or schedule usually reveal a best or minimum application, best schedule etc….. absent any glaze defects like crazing etc… generally visual observation and correlation to how the ware was prepared.

Not to worry, folks have made glazes forever and experimented looking for predictable ways to characterize what happens. They publish their findings or research and you get to decide if it is useful to you. Commercial glazes have the issue of - what is in them and how does one correct a defect such as crazing. The good part is commercial glazes don’t use lead anymore (for the most part), vanadium pentoxide etc… generally because someone found out it was a bad thing. If you mix your own then you know what is in it and can reasonably test for durability, fit, etc…. to your satisfaction, before selling it or giving it as a present for human consumption. I think it does help to inform but definitely not for everyone.

Not to worry, folks have made glazes forever and experimented looking for predictable ways to characterize what happens. They publish their findings or research and you get to decide if it is useful to you. Commercial glazes have the issue of - what is in them and how does one correct a defect such as crazing. The good part is commercial glazes don’t use lead anymore (for the most part), vanadium pentoxide etc… generally because someone found out it was a bad thing. If you mix your own then you know what is in it and can reasonably test for durability, fit, etc…. to your satisfaction, before selling it or giving it as a present for human consumption. I think it does help to inform but definitely not for everyone.

Ok, everyone has to cheer for my IG friend Renu!
(You don’t, but I will be. She’s the sweetest person, and she’s the art teacher that everyone has super fond memories of.)

Thanks everyone. Kiln is on with Alumina dusted between the sheet. Fingers crossed it works. Ill let you all know how it goes
 

As I see it, there is a lot of good work establishing ground zero for the perfect glossy durable midfire glaze - flux ratio of 30:70, Si and Al molar within limits, Si:Al ratio around 7-8, boron molar within limits, etc. Yes, perfect, but boring glazes. Mayco Stroke and Coat, a solid performer from 06 to 6.
In my glaze chem classes, I tell them to consider theoretical perfection, but also realize there is are a lot of more interesting effects to be found outside of ground zero. Some of it may not be durable, though some may be just fine, do your tests. I have to this point stayed away from subjective experience with this particular recipe, but one of the reasons it is so popular in my community studio is because of the interest it creates. When layered with certain others of the studio glazes, we put the Amaco drizzles to shame. It is a solid glaze by itself, or Amaco/Mayco Flux in the same bucket.
Why? In my studies of glazes, it is the high boron in this one when layered with other lower boron (conventional theoretic levels) glazes. Higher boron levels create a borosilicate glass. Lower boron levels create an alumino-silica glass (not quite soda-lime bottle glass, but the chemistry is moving in that direction). Layered borosilicate glass and alumino-silica glass do not mix to a homogeneous blend, but rather they are immiscible and flow through each other in rivulets or create a faux-oilspot effect. Now I have the student's attention (and if they are not careful, a kiln shelf to clean). As DuPont said 90 years ago, better living through modern chemistry.

Katz himself might have thrown a wrench in the works in regards to his testing into flux ratios, also into further exploration into silica:alumina flux ratios. From his 2016 NCECA presentation taken from this pdf.

Can they have an unglazed bottom or foot ring to allow for display? If not, how about casting a sacrificial ring or tab (maybe 3/16” diameter eyelet) into the bottom, suspend while firing, grind off after finished and finish the remaining dot with paint, or a bigger dot and insert logo?  
Just thinking …….

Thank you Bill. I would never have thought of that . I think I will try your suggestions. Sandi

@Min et al, I just pulled the tile after 24 hours half submerged in 30%* cleaning vinegar. There is no change in gloss or color (we use this glaze with a bit of copper and some tin/zirco for a nice turquoise). I will go shopping to find some plain lye (Drano brand has other stuff in it) - when home-brew testing, I like to hit the sample tile with something stronger than kitchen cabinet chems (since I run my dishwasher so infrequently, it would be next year before I would complete the Katz-recommended 30 cycles...).
*Grocery store vinegar is diluted to an acidity of 5% - sometimes. In recent years as manufacturers everywhere try to reduce costs by invisibly reducing quantity in the same package, some grocery vinegars are now 4%. That might not make any difference in your oil and vinegar salad dressing, but if you like to make your own pickles, you need to check the label and make sure you are getting a 5% vinegar. And there, I did it again, took the pottery discussion in another direction. Now we can share recipes for pickles...

Can they have an unglazed bottom or foot ring to allow for display? If not, how about casting a sacrificial ring or tab (maybe 3/16” diameter eyelet) into the bottom, suspend while firing, grind off after finished and finish the remaining dot with paint, or a bigger dot and insert logo?  
Just thinking …….

Hi Bill, your responses really helped me understand more about how things work! Super helpful.
Snickerhaus - I built a pottery shed in my back yard a few years ago, and had an electrician install a 80 Amp 240 V circuit that ran from my main electrical panel on my house.
While heavy gauge wire is expensive, the materials cost (wire, conduit, breakers) was less than the LABOR cost from the electrician to install everything. The lesson I learned was to plan for the most amperage/voltage I could imagine ever needing, and have the electrician install the needed wire and breakers. It cost a little more up front, but again the main cost for everything was the labor itself. Now I can move to a larger kiln in the future without worrying about doing another round of expensive electrical upgrades.
Hope that perspective is helpful.

Thank you!!
As an update:
- I replaced the breaker with a standard non-GFI breaker and all is working fine (the original GFI breaker was for my home brewing setup)
- also, thanks on the info on venting, my wife sincerely appreciates the guides!  She had been using the kiln without the benefit of any manuals in the past.
- Fascinating info on  firebrick conductivity, @neilestrick
We got things working and did our first firing last night.

@SolidCitizen Vented used to mean propped, perhaps with a peep hole or two out. Some kilns came with a small L shaped prop build into the lid, for others folks would prop the lid and inch or so with kiln furniture to vent. Usually in the first portion of the firing to let out any minor amount of water (steam) being released.
If this is on a 2 pole GFCI breaker and the breaker trips then there is leakage at that level. (About .005 amps directly to ground) some GFCI breakers are sensitive and will nuisance trip so changing to a new 2 pole GFCI may work. If this run is out to a garage, the quality of the wire, connections etc… can contribute to the sensitivity. Any junction that is wet or moist can cause minor leakage.
In my view,  if it is tripping then there is leakage so solving that issue can be difficult. Lots of folks don’t run kilns on GFCI’s, just items within reach of water sources ….. sinks mostly. A well grounded kiln is important though so ensuring a good ground all the way back to the panel AND to a grounding source such as water main and driven ground rod is a must to protect from shock.
Here is a link to the old generic Paragon manual https://paragonweb.com/wp-content/uploads/IM104-Paragon-Ceramic-Kilns-April20181.pdf venting is explained among other things.
4 way rotary switch operation explained here https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/IM-55-Current-Flow-thru-4-way-Switch.pdf
A&B service manual https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/IM5-A-and-B-Paragon-Inst-Man-Jan2017.pdf
Your kiln by manufacture requires a 30 amp breaker, btw page 6 guide above.
Finally the pilot is likely 240 volt rated neon light. Double check the voltage stamped on the side and replace with proper voltage rated lamp.

Today I spoke to Jim from Evenheat, who offered to install a solid state relay free of charge. I'm mailing the control box back to him. I hope this is the solution! Thank you, everyone, for your extremely valuable input, I truly appreciate it!

OK, I tried that, nothing happened. I think we've rule almost everything out, except the TAP and some internal wires we can't see. It started after I incorrectly calibrated the screen. I looked how to recalibrate it, which also didn't work.
I'm going to call SDS tomorrow and see what they say. I can't believe it's the relays, 3 of which are brand new...

Yep, turns the relays on and off. Everything gets wired as full power and rhe elements just sequence on and off as needed to climb on schedule.

I used these from Euclids when I rewired my electric -brass and stainless -I added some copper coat as well to insure great long term corrosion free connection 
https://euclids.com/products/element-connector-large-2-screw?pr_prod_strat=e5_desc&pr_rec_id=82bd0e954&pr_rec_pid=5133891010605&pr_ref_pid=5133812236333&pr_seq=uniform

Only time I have seen unique circular and spiral failures were from the trimming and burnishing at the green stage, which in those cases very excessive. Was hoping your picture would reveal the actual crack / blowout.  Sorry, that’s all I have at the moment. Anything special to add about the throwing trimming process?
 
“Pictures definitely key here as I have seen circular failures and delaminating especially in bowls where the interiors were overworked in the green stage. Pictures and a little about any special throwing, trimming, ribbing, burnishing etc….  could help narrow this down.”

This may help - I like those as well but their mass is small so I personally have seen them fail on the highest loaded elements in the least cooled ares. They are not big enough or have enough surface area to keep the connection cool for the amount of cooling  air passing them.
Improving the cooling airflow can help if the convective flow from bottom to top can be improved. Reducing leaks out of the kiln by stuffing with high temp insulation can help for radiant and convective losses as well.
The simplest solution has been to extend the element pigtail more and position for best convective cooling, just to get some additional cooling to the connection.
conductivity plays a role so copper best, brass next,  followed by steel / stainless.  An old easy connector to build  is drill a brass bolt, use the bolt and two washers. Sandwich the wires between the washers through the drilled hole. Increased  convective cooling (heat sink)  easy to achieve this way, thermal conductivity less of an issue but surface area as well as mass very important. So this can be done with steel and stainless, just harder to fabricate and not thermally as conductive.
1/4” - 3/8” X an inch or two (Cooling surface area and mass) simple brass bolt and nut depending on the clearance in your cabinet can last forever and be very economical and easy to build.

GFCI outlets are not recommended for use with kilns. See HERE. 

Aha ! Better pictures. So it has terminal extensions. If it’s just not working then check the fuse between PIN number 11 of the power switch and pin 4 of the relay. Also check the lid switch if you have one, this kiln will not start without the lid down. There should be an adjustable lid switch that connects when the lid is closed. It may have bent or be slightly out of adjustment.
And not to forget to mention, ( not likely but….) the new crimp has to be crimped around bare wire, not just the outer plastic of the wire. A nice tight connection that cannot be pulled out of the connector.

@THW Aha! It's not an 8 tab, it's a 6 tab with a double connector. Okay, so that all good then. We just couldn't tell from the photo. In that case double check all the crimps and see if that helps. A bad crimp could definitely cause the relay to overheat and fail.

I think your diagram here https://www.evenheat-kiln.com/_files/ugd/3a9418_3f21adacb8c84a608e3481349c72110a.pdf. Looks like all crimps have been replaced at one time or another. What I don’t understand is the extra connections to the normally olosed set of contacts on the relay. This is not shown on the diagram, can you describe or show where all these lead?
On most relays the normally open contacts will be rated for high amperage - 20-25 amps something like that. The normally closed usually will be a fraction of that, say 2-3 amps. Most kilns don’t use them yet your kiln has wires to them. Interesting. My best guess is someone got the double pole double throw relay and crimped extra connectors on instead of combining the wires as shown in first drawing.
In the drawing below a red and black are combined on  terminal #4 and a red and white are combined on terminal #8. The way this is currently wired is likely a dead short or running full element current through very low rated contacts as soon as the power is turned on. You can use a relay like that, but two of the connections need remain  unused. The normally closed set remain unused. Just looking, the top two relay connections are not colored as published either and the missing green is part of the lid safety circuit.. Tracing all these out and matching them to the diagram is probably wise before firing it again.