Bill Kielb

You should measure approx. 25.2 ohms at the terminal block that feeds the four series wired center elements per the wiring diagram. If they measure appropriately then trace the wiring back checking connections to be sure they are powered. Please don’t forget to disconnect all power before checking things.

Again, if the middle elements do not glow, they are hooked DIRECTLY to the sitter. No relays, no interval timer, no nuthin. If they do not glow, there is a break in the wire, connection or since they are series wired, one or more of those four elements. They connect straight to power from the sitter and run continuous from start to finish. If they don’t glow, as in the picture, they need to be investigated. Since the top ring and bottom ring do glow - for now - it appears the relays and timers must be working.

Nice! It’s hard to tell from your picture, but the middle set of elements should be powered all the time the sitter is on. They appear off to me in the picture. so if they don’t glow at some point then somewhere there is an open circuit and it’s unlikely related to the timers / auto manual switch.

Looks like #40 is more correct. Their new kilns are 240000 btu and …… my mistake #40 might be a bit large in the 6 burner so #50 gets you closer. Decent table here:http://www.davegardner.org/images/GasInfo/OrificeTable.pdf If you are lucky it is on the kiln tag. Looks like you want to max out at 240,000 btu by todays standards which means #50 or slightly larger, closer to # 48. If you drill them yourself and don’t leave the conical approach in, they will not perform quite as well as if manufactured. If you have #40’s in there and decent blue flame then I would definitely work the damper. Small (very small) adjustments will have very dramatic effects once you get closer to reduction. You. Want to keep as much heat in as practical, just short of reducing. This changes as the fire progresses and as the operating pressure increases as well. updrafts can be tricky (especially a small kiln) but folks have fired them for years so they can be mastered. It does take a reasonable amount of patience though. It would be great if you could watch someone fire successfully. When we do this usually folks observing see a few things that they never would have realized. Demonstrating the dramatic affect the damper has often enlightens may so maybe seeing is believing I guess. zehat are you using as a damper?

#40 orifices are larger than # 50 and # 60. With #40’s and a blue flame you max out at about 37000 btu per burner, which would be about 225000 btu for all six. That’s a lot of energy for a small kiln. So stalling can be because of atmosphere but is often because of damper adjustment. Especially this kiln. Really small adjustments are needed to maximize the energy in the kiln and just keep it out of reduction. When I say really sensitive, I mean 1/32” or less to trap as much heat as practical while just staying out of reduction. I would also double check sizing and pressure - #50 orifices net about 34000 btu per burner, #60, 11,000 btu pr burner so a huge disparity there so likely some misunderstanding.

Looking at your diagram, the bottom elements are series parallel so for the two center to be out and the outside to be working one or more are broken or they are not connected as in the diagram. The center section is series wired but constantly powered so my guess is one or more of those elements is broken. So I would check ALL for continuity, individual if possible if you are not comfortable with the mix of series and parallel wiring. The auto switch and timing relays at this point are secondary, I think you will locate the bad elements / connections.

First, elements wear together so replacing just a couple is interesting but maybe not the norm. Anyway, let’s assume all the resistances are truly good. I believe this kiln has the interval timer and repeat cycle timer and a low manual and auto position. Have you tried operation in manual mode? (Rocker centered, not left and not right, just centered) If yes, can you determine if the interval and repeat cycle timers are functioning. post a picture of the equipment tag and what cone are you routinely firing to? picture size - (one way) you should be able to email the picture to yourself and most email programs will ask if you want to resize.

Pickle fork is a common automotive tool for tight spaces

You just need a few trips to the space station or book some flights on the Virgin Galactic space line.

I think my best guess initially was layers which would seem to lead to color and transparency of the layer. Reduction could bring into play: copper concentration, level of oxidation / reduction, etc….. , not necessarily a direct function of copper reds but their tendency to be very red when fully reduced and often green / grey when re oxidized. I suspect layers of different colored glaze would behave in a subtractive manner and level of transparency would also significantly affect the color viewed. Definitely an interesting piece though.

They are definitely heating, so some power wasted. If there is enough wire, I would cut them back to clean wire and install a new connector. Even though they are discolored, they very likely only consume (or waste) a small amount of energy. They will continue to heat, which causes a higher resistance which cause more heating, so they won’t improve on their own, they will slowly wear out. Again IMO very proactive - new crimps on new clean wire. Super proactive - buy a new harness.

Maybe …………… They almost seem to be layered, so the difference in thickness likely influences the non reduced color. A very cool overlay effect! Interesting also, usually (not always) the interior of things can be reduced more fully because they are in a less turbulent air stream. Pretty cool effect though.

I routinely do both, however easiest to bisque fire the underglaze for the ease of handeling while completing the decoration. I spray most of my glazes so really this poses less of a concern. What I have found, regardless of the application the underglaze and overglaze really need to be tested together. Some combinations shift color, some overglaze has a bit of difficulty melting properly over various colors and makes of underglaze. It does not sound like you have time to test, but it is really the only way in my view to get an expected result. We spent a whole summer testing and finally made our own clear gloss and matte that melted well over various colors, thicknesses and brands so our brush artists could paint, blend, shade in a normal fashion without too much worry.

So going by the nameplate 220/19 = 11.57 ohms and 220 *19 = 4180 watts (which ought to be somewhere on the label of the kiln) ……. so at the new residential voltage of 240v, 240v / 11.57 = 20.74 amps. Circuit breaker Minimum Size for continuous load (kiln) = 1.25 X 20.74= 25.93 amps. Maximum breaker size = 1.5 X 20.74 = 31.1amps. So if we believe the kiln label then 30 amp breaker is fine, (20 amp breaker) would be too small. #8 wire is good, slightly over rated so very good. Now, please confirm your wiring is at least #10, your breaker is 2 pole 30 amps. From there, something burned so could be a loose connection at the plug, or plug to kiln or elsewhere in the kiln at element connections etc…. It’s important to find it. Since you could smell it and the kiln did not reach temperature it seems near for sure that the defect exists and must be diagnosed before you can safely move forward. One easy way to shrink your photos (among many) is to send them by email to yourself. Usually most email programs allow you to reduce the size while attaching or before sending. Photos definitely would help folks here see things more in context.

What comes to mind is light compound and a small polishing wheel. Definitely would test light, and medium compound before going all in.

It can be removed and these finishes do wear away over time. You may be able to scrape away and gently Polish the glaze if damaged. I think it might prove difficult though, but again masking the good surface could protect it from polishing damage. It should have melted a bit into the softened glaze though, so fully restoring might be really tough. Those small solid figures are probably ideal for your crikut though. As shapes get bigger and fit over bigger curves on the vase keeping a tight seal becomes more difficult. Nice piece. The rim and bottom are definitely a possibility for decent masking tape though for the string straight line.

One possibility - is the atmosphere. To maintain reduction, especially copper reds one needs to provide a rich carbon monoxide atmosphere. If sufficient oxygen is allowed, the the piece simply reoxidizes to whatever extent it can. I should add, small a small amount of tin is usually a very important component for copper red glaze recipes and can have a pronounce effect on copper reds. Not sure if there is any in this recipe though. The example picture below contains test tiles mapped at various places throughout the kiln. These mapped tiles along with the pressurization schedule for the kiln often provide a way to ensure future firings are reduced evenly for that kiln with that specific pressurization / atmosphere. Copper red is very sensitive to reoxidizing so often a nice way to test.

Post a picture of the kiln nameplate, what I can find is a kiln that draws 24 amps (if this is truly your kiln) which would require a 30 amp breaker minimum. Kilns need the breaker to be at least 125% of the load, not more than 150%. The wiring, receptacle etc… ought to be sized accordingly. For now, if it smells electrical it very likely is so finding this before operating it again is necessary. Your kiln is old so it was rated at 220v. Todays voltage is 240v, so it is possible it draws even more than the 24 amps which gets you into the next sized breaker at 35 amps and associated rated wiring etc… post pictures of the name plate, cord, receptacle and wire size if you know it. Kilns are a bit specialized in their electrical requirements so better to be safe as practical with a burning electrical smell and non functional kiln. I found a wiring diagram and looked up in an old cress manual. Both point to the need for at least a 30 amp breaker and number 8 wire (rated for more than 30 amps) I did find a website reference for 19 amps, but did not find Cress recommending this.

In North America NEC has always sought to use them in wet locations or potentially wet. Within six feet of a sink, exterior receptacles, receptacles that power wheels (very wet). Having said that you can buy a GFI 2 pole breaker for your kiln. Will it nuisance trip because of the direct contact with the brick and live elements? Probably not, but it only takes a tiny bit of leakage 0.004 -0.006 amps to ensure it is non Lethal. Here we have split phase 240v with 120v for most convenience and appliances. Elsewhere you will often find 240v single phase (1 hot leg and one neutral) so that friendly lamp cord is carrying twice the voltage and maybe a bit more potential for leakage. GFI protection for most of their downstream loads is common and safe practice. Do they run kilns through a GFI, yes they do.

Yes anything is possible, but I have never really found that special slow speed for quartz inversion. Fast conefire programs in the Bartlett controller can be anywhere from 150f to 570f per hour. Slow speeds 100f - 400f per hour. Since thousands of pots go through this daily (often fairly unevenly) I just have never found a credible “slow” speed. On cool down most are subject to whatever speed the kiln goes naturally. I guess if you find a speed that works for you, use it. As far as crystobalite, that’s quite a list of things before one starts thinking about it. I guess in the end, do what works for you but clay is really tough stuff. I suspect quartz inversion and crystobalite likely get blamed for lots of things. One of my instructors would say:”stop blaming the kiln, make better stuff”. In my experience I have found that to be reasonably pertinent.

Generally China paint / lusters go as fast as you can. Truth be told, Cristobalite is just plain hard to have and everything goes through Quartz inversion. Hundreds of thousands of pots each day up and down slow, fast, unevenly. Clay is tough, this is just something that happens. For the most part good clay theory to know but rarely affects typical potters.

Yes, IMO this does work for other gypsum and plaster surfaces. stucco, interior plaster walls, cement …… kill the mold, power wash clean when possible, dry thoroughly and seal as practical to reduce the absorption. Painting interior plaster surfaces has always been the norm to add significant longevity to them. I think it’s a good practical idea. For this: making sure all mold is killed, non destructive cleaning, thorough drying, then painting to preserve the fine detail would be some thoughts that strike me. As always testing thoroughly prior is key to me.

First total guess, I think it’s far more likely the circuit breaker has tripped rather than the sitter switch disconnected without tripping. Either are possible so please cycle the circuit breaker completely off then on. Now, onto diagnosing. Tell us the make, model of the kiln and all the info on the electrical tag mounted on the kiln, then tell us the breaker size etc…

I do not. Not knowing the limits of the materials here …….. there are many mold removers used for plaster, stucco, cement. This is such a precious piece and from what I know of the residence time to kill mold which is significant. We are not even sure it is mold. I think best I can speculate, dry it out thoroughly and have someone recast and make another mold. My heart truly goes out to CharliesMomma and feel I would try and do anything non destructive to reduce the risk of losing this piece or the precision and original character of it. To me — make another mold first before experimenting with chems and scrubbing. Having done that, then yes gentle cleaning and sealing would be something I would cautiously test and try.

Neil pretty much summed it up but I just would add …..extension cords will likely have losses. If the cords warm at all, then that is wattage wasted not getting into the kiln. You are already challenged with not enough heating (watts … =3.41 btu per watt) so any losses here or warming of the cords could matter. Never a good idea to extend kiln power with extension cords btw.