Jump to content

Dick White

Members
  • Posts

    973
  • Joined

  • Last visited

1 Follower

Profile Information

  • Location
    Springfield, VA USA

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

Dick White's Achievements

Advanced Member

Advanced Member (3/3)

725

Reputation

  1. Parts for a kiln sitter can also be purchased from Clay-King https://www.clay-king.com/kilns/kiln_parts/kiln_sitter_parts.html The motor for the timer is part number 67 for $98.
  2. Both the Skutt and L&L kilns have a full-height control column for the digital controller with fiddlie electrical connections to the elements that make it very inconvenient to casually take the sections apart for loading large sculptures. Note also that while both use a 60 amp circuit, the Skutt 1027 kiln is smaller total volume and is rated for cone 10, while the wider L&L e28T is rated to only cone 8 (generally regarded as usable to cone 6 in the long term) because of the greater volume. You might consider instead the L&L Jupiter series. The individual sections are not hard-wired to the inside back of control panel, but are plug-in to the side of the control panel. There will still be some disassembly needed to take the sections apart, but would be easier than either the Skutt or L&L e-series kilns.
  3. Can you share them with us. There may be several different things you can do, depending on what's already in the recipes.
  4. Joining @Babs in recommending against wrapping a kiln in an additional layer of fiber. The fiber will trap some escaping moisture against the metal shell, resulting in more rapid rusting of the metal parts. Kilns that have a layer of fiber around the bricks have the fiber inside the metal shell, directly against the brick.
  5. The manufacturer's address on the label is a city, zone, and state, i.e., pre-zipcodes. Zipcodes were implemented by the Post Office in 1963. That gives you a marker for the kiln's age. The electrical rating is 19 amps @ 110V, or about 2000 watts. The apparent size of the kiln plus the low watts of heat suggests it will not go past earthenware temperatures.
  6. The files are just one long list of the status of the firing every 30 seconds. They are in .csv format, which is one of the formats that the usual spreadsheet suspects (Microsoft Excel, Open Office Libre, Apple Numbers) can open. Once the list is open in the spreadsheet, you can look for unusual events, or do some calculations on the actual temperature changes over 1 or 5 or 10 minute intervals to compare to what was programed. And if you want to get fancy, use the graphing capability of the spreadsheet to draw a picture of the temperatures over the duration of the firing.
  7. And when diving deep into the UMF rabbit hole, several other things become apparent. Boron is not a flux. Fluxes create a eutectic with the silica and alumina to cause them to melt at lower temperatures. Boron is actually a stabilizer (R2O3, like alumina) but melts by itself at such a low temperature that it needs no assistance from a flux. It brings the other oxides into the melt simply because it has already melted. Also, the other fluxes each impart unique properties to the glaze aside from their melty-ness. Lithium is a more powerful flux, but too much messes with expansion (it can both craze and shiver). Shifting the balance of sodium vs. potassium can result in different color responses from some colorants (e.g., copper). So much of glaze chemistry cannot be demonstrated simply by the numbers - experience and testing is how we sort out many of the variables.
  8. Sno Industries has been out of business for a looooong time. If you look at the manufacturer's label and the address does not include a zipcode, that is a sign that it was manufactured before1963 (that's when the Post Office started using zipcodes). As Bill points out, the maximum temperature is a function of the power (in watts) of the kiln elements vs. radiant heat losses through the shell, through both the side walls and the top and bottom. The bricks are not perfect insulators, and the amount of heat lost through them increases with time and temperature, as the brick becomes saturated with heat and insulates less. 120V kilns typically generate 1800 -1900 watts (a big hair dryer) as any more than that will blow the typical household circuit breaker. Current cone 6 rated commercial 120V kilns are all smaller than your kiln and have 3" brick, so the available wattage of heat from the elements disperses less through the walls of the better insulated, smaller kiln, and thus can reach a higher maximum temperature before stalling when radiant heat lost equals heat input. I have done some of my own rough calculations on the entire Skutt and L&L lines using rated watts of heat, external shell dimensions, and manufacturer's stated maximum cone. The typical cone 10 kilns generally had at least 3½ watts per square inch of external surface area. Kilns rated to cone 8 (but only good to cone 6 in the long run) had about 3 watts per square inch. Kilns rated to cone 6 (which would go through elements quickly if consistently fired to cone 6) had between 2½ and 3 watts per square inch. And kilns rated for less than cone 6 had less than 2½ watts per square inch. Your kiln is looking like about 2 watts per square inch of external surface area, not likely to reach cone 6 IMO. As Bill notes, you can wind your own elements to any specification you want to get more heat, but more heat is more amperage of electrical service, and your house wiring needs to be able to support it. An option, if you are going to rewire the kiln - convert it to 240V. You will need to do a bunch of calculations to match your new element windings to the kiln wiring and house circuit, but it can be done.
  9. To calcine clay (ball or kaolin), just put a big bisqued bowl of it in your next bisque firing. Unlike some other materials that might sinter if calcined to too high of a temperature, clay is refractory and can withstand bisque temperatures, so just use your next bisque firing for calcining it rather than using your propane for firing a single item.
  10. In the UMF calculation, the underlying notion is that you are counting the number of mols of each of the usual ceramic oxides, and developing a ratio of the number of each in a sample. A mol is simply a chemist's unit of counting. One can have a dozen pencils (12) or a ream of paper (500 sheets). A mol is ~6 x10^23 atoms or molecules (6 bazzilion). After doing all the math on the molecular weights of all the various oxides in a recipe and then reducing the sum of the flux molecules to 1 mol, the number of mols of alumina, silica, boron (the most important of the non-flux oxides) in the recipe sample will also be calculated. For the 1 mol of flux molecules, you can have innumerable ratios of the individual flux oxides within that 1 mol. For example, you might have .35 mols of sodium and .55 mols of calcium and .10 mols of magnesium oxides equaling the 1 mol of total fluxes. Once the 1 mol of fluxes has been set, the number of mols of the other oxides is revealed. For a typical cone 6 glaze, the quantity of alumina oxide will often fall between .25 and .5 mols, the quantity of silica oxide will often fall between 2.5 and 5 mols, and the quantity of boron oxide might be around .15 mols. These ranges are not required amounts, but rather are generally accepted targets for a stable glaze. There might be other reasons you want a glaze that is outside these typical ranges, but knowing how the ratios relate to each other will allow you to adjust a glaze recipe by adding or subtracting particular materials that have the oxides that you are trying to adjust. For example, if you want your recipe to have more sodium oxide in the 1 mol of fluxes, adding whiting (pure calcium carbonate) will not help. But if there is whiting in the recipe, you can subtract some of that to cause the balance of sodium within the 1 mol of flux to go up.
  11. We have been using Advancers in the glaze kilns at the college for over 10 years. Costs were not an issue as we got grants. The main reason we liked them so much is they are nearly indestructible (if you treat them properly). With student glazing errors, drips pop off with a stiff putty knife and a few swipes with an old green grinding wheel held sideways cleaned up the rest. No more chiseling and grinding divots into the corderite shelves, no more kiln wash. When we bought new kilns at the community studio, I just told them to buy Advancers for the glaze kilns. Same problem with everybody trying to do the Amaco drippy layered look and causing puddles of glaze on the shelves. Maybe in your own private studio, you have better control over your glazing, and when you make a mistake, you learn from it (which the students and community users don't pay the price for their errors). In my personal studio, I do some crystalline glazes which, by definition, are runny. Sometimes the catcher pot breaks from the stress. Advancers to the rescue.
  12. Two similar elements connected in series will generate one/half the heat of one element alone. Two similar elements connected in parallel will generate twice the heat of one element alone.
  13. Often, that clicking sound indicates the bat is not securely fastened to the wheel head because the bat pins are not securely fastened, and both the pin and the bat are wobbling. I lot of potters I have observed believe it is sufficient to just stick a bat pin in the hole and it will solidly stay there. Until it begins to wobble in the hole with the varying pressure on it while centering. Others know that the pin will be loose in the hole and try to accommodate that by wrapping a bit of paper around the pin before shoving it into the hole. Until the paper gets wet and the pin begins to wobble in the hole. The solution is wing nuts to tighten the bat pin to the wheel head from underneath. Wing nuts take some facile finger work to get them started on the pin, and more finger/thumb strength to twist them tight. Sometimes they will work themselves loose and the clicking is the signal to stop and tighten them again. As for the one oblong hole on the bottom of the bat, note that the oblong dimension is aligned with the radius (diameter) of the bat. That allows one to get the first pin set and still be able to move the bat crosswise to set the other pin. The movement is restricted to across the diameter of the bat, not tangentially around the circumference of the bat. Once set the bat should not move either crosswise (because the hole for the other pin exactly fits) or around the wheel (because the oval hole does not have any tolerance in that direction). Thus, the only possible movement is a loose pin not firmly tightened against the wheel head.
  14. The OP shows a location in the UK and price limits in pounds. The standard electric service there is 230V. In the US, standard residential electric service is 120/240V, where the normal household receptacle is 120V and other special purpose receptacles are 240V. Thus, in the US, there are a variety of kilns designed for either 120V or 240V service. I don't think there will be any 120V kilns in the UK, but I could be wrong.
  15. All the time now. Gerstley is gone and Gillespie is not a perfect match. 3134 requires a complete rewrite of the recipe. Custer is gone from the market, but I still have some. G200EU might be ok, haven’t tried it yet. Still have some old Amtal talc, but some Fabi is in my future. What’s next?
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.