Bill Kielb

Cones are easy, If you want to follow the cone chart then for your last segment go 60c/hr in the last 100c of the firing to 1222c. So pick a cone, let’s say 6. find the temperature in the 60c per hour column = 1222 subtract 100 from it, 1222-100 =1122 program your final segment to start at 1122, go 60c per hour and end at 1222. the last 100c is super important to the heatwork done. From the times you state though it does not appear your kiln is keeping up with the program and therefore likely worn elements. For a worn kiln you may be able to use the 15c column which means for cone 6, your ending temperature is 1185c, final segment is 1085c => 1185c and final segment firing speed is 15c per hour. There is a limit to how slow you can go and how glazes perform. As far as cones and many other things, In the final segment It’s rarely only about top temperature. As an example, just like baking something, it’s not simply 170c, it’s 170c for 30 minutes ………. For kilns we depend on rate per hour though. If you cannot find elements Euclids.com can likely wind new and they ship worldwide.

Just a note, the separation thickness definitely has a major impact on holding power. A friend - very accomplished potter - has been rehabbing both arms after major surgery and needed to resort to trial and error for her throwing thickness. As part of rehab she has been making small pots / bud vases over time to rehab …… lots of them thus far, so speed and ease in glazing led her to the magnets. Separation between the magnets has a giant effect that likely requires testing to figure out.

Cress is still in business so manuals and wiring diagrams available. Knowing the nameplate data and operating voltage would be helpful as this kiln appears to have been made in 208v and 240 v models. https://www.cressmfg.com/resources/ hope that helps.

Yes definitely possible. So silica and alumina do not melt basically on their own below about 1600c/3000f. So they need flux to help melt at a lower temperature The fluxed reaction pretty much takes place in the last 100c of the firing, prior there is just not enough energy to get things going. So temperature and firing speed in the last 100c is super critical, to which PeterH has posted the Orton cone chart above. As kiln elements age their power decreases and eventually they can’t make a reasonable final firing speed and things begin to over fire. The same goes for anything that slows down the firing such as worn elements AND a cold external firing temperature. In the end though -9c is cold but not that cold so likely the elements are fairly worn. How many firings are on them and to what cone do you routinely fire?

If I was recreating that I think I would paint the blue with underglaze including the wash effect then overglaze with a matte clear. Likely a glossy clear or decent liner for the interior and matte for the exterior, since they are all functional. if I was dead set on matte everywhere, inside and out then I would try and make sure the interior was more satin, not as prone to metal marking and reasonably known to be durable. So to me, the underglaze and artwork would be a yes and the matte clear would be a matter of if you could find a matte you like. If this was sculpture and non functional then I could just underfire the commercial matte to make it more matte and see if I could find a temperature best look combination. If I were mixing my own glazes (cone 5/6) then I would just dial in the amount of matte / gloss I wanted by varying the silica in the recipe until I got the level I wanted. Here is a recipe formulated very dry or matte and will go to full gloss as more silica is added. You are welcome to try, this is not for everyone though. Some folks love it and for others, not so much. https://glazy.org/recipes/19734

The short answer is to fire the ware to planned cone but use a slow or bisque type schedule. Not all clay / glazes work for single fire so experimenting or testing is super important.

Without going into many paragraphs, all those firing techniques have characteristic looks with traditional wood being the hottest and likely the most random to let’s say cone 12 ish. Gas and electric are just different types of fuels, but gas traditionally would go to cone 10 and is also ideal for reduction where a handful of oxides are affected by a carbon monoxide rich atmosphere which causes variation in color and influence some oxides to be less refractory than in oxidation. Electric is mostly reserved for cone 6 and below and can be associated with brighter colors, less energy use …. Cone 6 oxidation electric is probably most popular for studios and hobby. Of course there are exceptions to all the above.I think the best way to begin to understand is to know the typical cone and look at as many pieces of each as you can fired with different fuels. This will give you an idea of the look and typical temperature, clay and glazes required. That IMO would be a good start, but as with most things in ceramics one can spend a lifetime learning the firing skills, glazing techniques, throwing techniques etc…. To provide a desired artistic look. For a start learn the look in common with each technique then if interested, learn the materials and process.

Those are pretty close cone wise but a tad over fired or strong cone 6 so you could tweak slightly with offsets. My guess is your glaze is happier at cone 5. Glaze firings generally can go fast. Since the ware is dewatered and all the organics have been removed many find their glazes work just fine with medium or fast firing. Having said that slow bisque is more popular to remove all organics. Darker clays generally slower than light. Since you have so many pin holes there could be several causes originating with how well was the clay bisqued, how evenly was the glaze applied, is it really a cone 5 glaze. From the picture, it looks over fired, so to start properly bisqued test tiles, one two three coats of glaze etc…. Fire to different cones. For problematic or fussy glazes and clay body combinations they can be dealt with a drop and hold schedule or other methods as appropriate. First thing IMO is get all the prep stuff right and test (using test tiles) to then see what is the best way to fire that clay and glaze. I believe that is a commercial glaze and some of my very first pieces used it in layers to get the look. Temperature sensitive, base glaze sensitive and thickness sensitive from my recollection if it is the same that I used. These inconsistencies drove me to learn as much about glaze as I could find time for…… so I could just mix my own.

I just happened to look in the latest manual. The math, code requirements, and current Skutt manual seem to all agree so not sure what any distributor is saying but could be an error or a result of previously using lower system volts. Older manuals seem to show it as #8. I guess the lesson is always double check the math, pick an appropriate breaker and pick the wire. The more heating in the wire, the less heating in the kiln. Bigger is usually better for the kiln owner. If you are using roamex then the wire size will likely be larger. The adjacent conductors in a confined space tend to heat more and are derated from free space. The rule about breakers is all about reducing the heating on the breaker so it remains dependable. Heating in wires and devices is not really good.

I think it is a tweener. The Skutt manual I saw listed # 6 wire, no breaker. Sizing this not less than 125% and not more than 150%. 33.4 amps X 150% = 50.1 amp. So not more than 50.1 amps and not less than 41.75 amps (125%). One is left with choosing a 45 or 50 amp breaker each fit the rule. The Skutt kiln sizing in the manual seems fine.

Bricks do stay intact but an extremely interesting question. Lead at one time was used as a flux, no longer. One of the insidious issues with lead is it gets absorbed or transported to everything. You could do a couple lead swabs on the bricks just to check. An automatic shut off device would be great as far as operating. This kiln may have a kiln sitter. Lots to learn for sure, understanding more about clay and what temperature you will be working in will become super important as to whether this will work for you. Post a picture or two, inside and out. This kiln is old enough so probably good to let folks here see it to provide more informed precautions. As far as an interesting story of potentially how to pollute an entire planet with lead google Thomas Midgley.

That kiln is basically my age and I inspect everything when I wake up just to be sure it all works. Just kidding, I would inspect all the electrical and make sure everything is safe and in order. Hook to a properly sized circuit breaker with properly sized wire should be fine to try. Are you planning on firing to a specific cone, will this be for firing your work or is this something you would like to be sure functions prior to sale?

I would search white and cone 6 for temperature then look at the pictures https://glazy.org/search?keywords=White&base_type=460&cone=30&photo=false&production=false Here is one with movement https://glazy.org/recipes/3019 and another …. might need more color though https://glazy.org/recipes/3022 and a third https://glazy.org/recipes/195539 Drippy movement https://glazy.org/recipes/175463 (Low Alumina) Less movement https://glazy.org/recipes/3136 Look for similarities, those with lower alumina generally will move more than high so something in the 0.3 range is much more likely to move than something in the 0.5 range.

Its just a function of how they are hooked together. Two 30 ohm elements in parallel will measure 15 ohms. Neil knew that and gave you sectional measurements so you could check them while connected because of the crimped connections. No worries, time for new.

Here are some thoughts: that error message can mean it’s not connected ( which you confirmed by disconnecting) an open circuit (Defective thermocouple or loose wire), or the leads reversed at the board or the thermocouple holder (check polarity, from thermocouple back to the board) you can bench test the thermocouple by hooking it to a voltmeter and measuring the millivolt output at a temperature and comparing it to the appropriate chart. In and around room temperature it’s approximately 1 millivolt for common type K and the voltmeter will tell you which lead is positive Other tips: the yellow (USA) is positive and non- magnetic, the negative is red (USA) and slightly magnetic.

Pictures of old, new, circuit board could help

This may help along with Peters chart. You are likely checking between 3 types: K, Type R, and Type S so if those colors are present on the old thermocouple it would be great to note. A picture of the back inside of the control board likely reveals a jumper setting or terminal marking could give a clue. Pictures here likely very helpful

It’s an excellent point and possible under very special conditions and temperature rise (UL sets this as possible). But again if it’s a vent-a-kiln as the op specified, the duct will be near room temperature air. If it’s a downdraft that @Hulk mentioned then properly adjusted it will supply 100-130 degree air as the minor amount of kiln air must be diluted with room air in the mixing manifold at the kiln. Standard suspended single wall ductwork generally applies. Double wall and special clearance requirements generally apply to ductwork venting gas fired appliances. Ensuring this is operating as the manufacture specifies is probably most important to get right and following the manufactures suggested venting requirements when extending.

If it’s a vent a kiln then you have a hood that is going over the kiln. It will draw room air so it’s not going to get very warm, beyond room temperature. Single wall duct and standard hangers. Distance should not exceed 10 ft without consulting the factory so definitely call them. Negative pressure is less likely to leak than positive. If you have a 5”265 cfm, then they Will likely suggest 6”round or better across the basement. If you have a 500 cfm then they will likely suggest an 8” round duct to traverse if you want to maintain the rated cfm . All of the extension ought to be hard pipe BTW, 30’ of flex would be doable but generally a bad idea.. suction is easier as all leaks are inward, pressure would generally require your best joints not to leak a little. Either will likely require a way to bring in outdoor air when running especially if you have combustion appliances. Best to consult the factory for your setup. Link to vent-a-kiln https://ventakiln.com/overhead-kiln-ventilation-systems/

The Whisper has always been the direct drive and brushless motor. Very easy to use as a turntable for decorations to spin by hand. No belt, no backlash when not powered. The VL lites have always been belted, so if still true, a bit noisy if you are not used to it. Some folks like the noise, I have grown accustomed to the quiet though. I do like my motorcycles rather loud though and postulate loud pipes saves lives. Go figure!

Since you have moved and this kiln requires special electric which includes a neutral in addition to the two 120v phases it is possible your new receptacle does not contain the required neutral. I would suggest confirming you have proper power. Your symptoms indicate you do not have a neutral. Paragon has parts, is still in business and has your wiring diagram and manual for your kiln in their archives. https://corp.paragonweb.com/support/kiln-wiring-diagrams/

I think they posted the glaze for its visual result and not necessarily for extended UMF requirements. The flux ratio is in a likely non durable place for many. Part of the problem may be (in the US) to be technically food safe there simply needs to be no cadmium or lead. It also could be just fine as a glaze for sculpture or non food use ceramic products as well. As others have pointed out there is a warning at the bottom for food safety, definitely always good to add a comment of additional warnings you may be aware of though IMO.

So here is a thought that may make sense and an idea for evenness. If your shelf is close to the perforated grill it restricts the gasses from leaving by way of the flue. If your shelf is elevated higher above the perforated floor, not so much restriction so …….. you may be able to control this by closing your damper more than usual. The consistency here is anytime your damper is opened too far your kiln fails to rise or begins to drop. Might be a simple way to control your firings no matter how you need to stack (within reason) to fit your wares. Easy to test out anyway. Second tool would be slow firing at the end. Slow down to 60c degrees per hour in the last 100c can help things even out.

It’s a 1/4 hp motor, so given the cost of a frequency drive or speed control and torque at low speed you may find all this very costly. Maybe even more costly than replacing with a dc motor and new drive. I helped a friend setup a new minarik drive last week, I think he paid 150.00 for it.

The glass item appears to be a reed switch. You would replace with a reed of the same or higher operating voltage and amperage while it needs to physically be the same size. The reed appears to be single throw, single pole - normally open. Goodwin definitely best choice.