LilyT Posted June 21, 2012 Report Share Posted June 21, 2012 I had to go back and look at your glaze firing picture again. Your glazework is so beautiful. As are the forms. Each piece is like a gleaming treasure. -Lily Link to comment Share on other sites More sharing options...
Mark C. Posted June 22, 2012 Author Report Share Posted June 22, 2012 To get this post back on track-I dug up another gas bill and checking my kiln logs (logging all fires has been a good thing for my whole life in ceramics) answering your fuel cost questions. My natural gas bill for march 21st thru 4/19 was 227$ That was for for two kiln loads in car kiln -Thats what I call them for 2 bisques and 2 glaze loads as well as one glaze fire only in small 12 cubic footer. I can do a what's one glaze fire cost as my summer production ramps up for a big show. Mark Link to comment Share on other sites More sharing options...
LilyT Posted June 22, 2012 Report Share Posted June 22, 2012 Hi, Mark, So nice of you to go through the trouble to dig up and correlate records. Also, impressed that you keep records and not misplace them after a few years :-). It seems that your total energy costs run slightly less than $3 per cu ft of finished ware. Whereas mine runs about $10 per cu ft. Bigger kilns are more fuel efficient I would presume? Also, I bet that you are more efficient firing than I am. All these details are interesting to know, I bet this is helpful for other real potters (like yourself and unlike yours truly). I know in some parts of the world, people can come by scrap wood and other more inexpensive materials to run a firing. But of course, then that takes your attention and time away from making pots to fiddle with a lot of cost savings measures. On an aside, I am looking forward to reading more about your glazing and firing process with the spoonrests (oh yeah, this was about spoonrests!). And I'm very interested in how you get such gorgeous colors. (I know the shapes3 come from talent and hard work) :-) Lily Link to comment Share on other sites More sharing options...
Mark C. Posted June 22, 2012 Author Report Share Posted June 22, 2012 The car kiln is home made by me. Soft brick arch roof and inner walls mostly K26s and a few K28s around the hard brick areas. It used to be k-23 but they wear out fast and I've had to rebuild it-as I fire this about 35-40 glaze fires a year with the same amount of bisques -I used to fire more but am slowing down as I age. The door of car is all fiber and two side walls are covered with fiber-the floor and fire box and flue is hard brick.The door is metal and the kiln roof has fiber over arch of soft bricks-the outer walls are hard brick as thats what I like to see-its more a visual durable outer layer-It takes about 12 hours to high fire from a cold. I go very fast up to my reduction temperature then it slows a bit-the slowest part is when the glaze melt is occurring. larger kilns can cost less to get more ware from as you noted-my little 12 cubic costs less than 12$ to glaze fire. Sound like you know your exact costs-I always have kept records of firing-that way you know what and when things happen-and can learn from them. I figure firing costs every few years but really do not get to caught up in it-what matters is clay makes more than it costs in the long run. I's a living for me-So its need to make money when its all done.The cost of a BTU is something I always look at on the bill. Mark Link to comment Share on other sites More sharing options...
LilyT Posted June 22, 2012 Report Share Posted June 22, 2012 Work efficiently in every part of ceramics comes with 39 years of doing it full time-learning........ There is the key. NOTHING takes the place of experience and education in ANY field. These shelves (advancers) give my an extra 1 to 2 feet of stacking space every glaze fire as well-As I fire a lot they pay for them selves very quickly even at 200$ apiece. In addition to the additional physical stacking space, the use of what are known as "low termal mass refractories" saves you on firing costs. My 3/4 " thick 18" x 18" traditional silicon carbide shelves are HEAVY. My 1/2" thick nitride bonded ones are much lighter. My 1/4" thick Advancers are featherweight! A good part of the heat energy used in periodic kilns (they type we fire) to bring them up to temperature is used to heat the kiln structure and the kiln furniture...... not the wares themselves. Less weight on silicon carbide (type) shelving material in the kiln means less energy is used to heat the shelves. (This is why industry uses ceramic fiber kilns and low mass furniture.... plus when you add in the concept of continuous kilns........ a HUGE energy usage savings.) A win/win. More space and less heat energy used. best, .......................john Good points noted. Buying better equipment can be cost saving in multiple ways. Link to comment Share on other sites More sharing options...
LilyT Posted June 22, 2012 Report Share Posted June 22, 2012 The car kiln is home made by me. Soft brick arch roof and inner walls mostly K26s and a few K28s around the hard brick areas. It used to be k-23 but they wear out fast and I've had to rebuild it-as I fire this about 35-40 glaze fires a year with the same amount of bisques -I used to fire more but am slowing down as I age. The door of car is all fiber and two side walls are covered with fiber-the floor and fire box and flue is hard brick.The door is metal and the kiln roof has fiber over arch of soft bricks-the outer walls are hard brick as thats what I like to see-its more a visual durable outer layer-It takes about 12 hours to high fire from a cold. I go very fast up to my reduction temperature then it slows a bit-the slowest part is when the glaze melt is occurring. larger kilns can cost less to get more ware from as you noted-my little 12 cubic costs less than 12$ to glaze fire. Sound like you know your exact costs-I always have kept records of firing-that way you know what and when things happen-and can learn from them. I figure firing costs every few years but really do not get to caught up in it-what matters is clay makes more than it costs in the long run. I's a living for me-So its need to make money when its all done.The cost of a BTU is something I always look at on the bill. Mark Hi, Mark, My kids and I were just discussing today how a car kiln would be so much easier to load, and then to get everything done at once. I'll have to share your construction details with them. I glaze fire as fast as possible to temperature (about 5 hours to ^10, 3-1/2 to ^5), my 3 cu ft kiln has one venturi. Then hold at temp and do a controlled firedown for 6 hours. After that the kiln is so small that it cools to 100F in 12 hours. I totally agree that it's best not to get too caught up in the cost details, there's only so much time and energy a person has, and it should be used to create. Still, it's interesting... especially if one has kids to raise and a house or car to pay off. How long did it take you to build your car kiln? Are you a welder also? -Lily Link to comment Share on other sites More sharing options...
Guest JBaymore Posted June 22, 2012 Report Share Posted June 22, 2012 I am going to try to split off the "forum software issues" postings from this thread into a separate thread. Then move that new htread to a different forum section (it clearly is not an "in the studio" topic). Wish me luck. Moved to "Business" section. best, ...........................john Link to comment Share on other sites More sharing options...
Mark C. Posted June 23, 2012 Author Report Share Posted June 23, 2012 Lily Todays gas bill 271$ includes 3 car kiln bisques 3 Car kiln glazes a few hours of another glaze as they read meter during fire 2 glaze fires in 12 cubic footer Still seems cheap to me. 129 cubic feet of finished glaze ware for 271$ Mark Link to comment Share on other sites More sharing options...
LilyT Posted June 24, 2012 Report Share Posted June 24, 2012 Lily Todays gas bill 271$ includes 3 car kiln bisques 3 Car kiln glazes a few hours of another glaze as they read meter during fire 2 glaze fires in 12 cubic footer Still seems cheap to me. 129 cubic feet of finished glaze ware for 271$ Mark Mark, Still seems cheap to me, too. But the ultimate measure is that your beautiful work is produced. Thanks for sharing! I'm also curious about how long it took you to build your wonderful car kiln. How many burners does it use? Did you design it all yourself? I know you mentioned rebuilding it, so 'm sure you at least modified it to work better for you. I am going to throw some spoonrests tomorrow :-) -Lily Link to comment Share on other sites More sharing options...
Mark C. Posted June 27, 2012 Author Report Share Posted June 27, 2012 I built this so many years ago in the 70's then rebuild in the early 80s after a potter partner split up. It was over a month to two-cement pad walls ,car, wielding-sprung arch -chimney Then again in the late 90s that time I wore out all the k23 bricks from use I also redid the chimney about 7 years ago as it had had it after 3 earthquakes and it was made from leftover stuff-now its all new and tight-the top 15 feet are 12 inch diameter stainless thick wall pipe-I like stainless for stacks it never wears out even on my salt kiln looks as new as the day I put it up. For many years this was fired for over 40-45 glaze loads a year and the same amount of bisques-that adds up as the decades slide by and wears on the refractories.I went thru silicone carbide shelves then dry press high alumina English shelves now for the past 12 years or more Advancers. All my shelves are 12x24s. Average load is 35 shelves. I tried lined fiber on the roof for about 5 years and tore that out and re-sprung the arch with k 26 and k 28s The burners are small 75th btu and I have 8 of them (a pair per burner port) with 4 ports-no safety stuff-all just old school seat of the pants ball valves-no pilots-Just the real deal. I light one set for candling bisque . No computers or ramping just common sense firing-old school-I do have an oxygen probe and digital pyro. on this kiln as well as another but can fire it all with out that stuff in my sleep-after all I fired so many kilns without any of that new tec stuff back in the day its like learning to ride a bike. I do like the extra info and it does make it easier with a kiln like this its very little to do for a fire once its above red heat or in reduction-just watch the cones and turn it off.You are connected to it more than say a computerized electric with auto shut off. Mark Link to comment Share on other sites More sharing options...
LilyT Posted June 27, 2012 Report Share Posted June 27, 2012 I built this so many years ago in the 70's then rebuild in the early 80s after a potter partner split up. It was over a month to two-cement pad walls ,car, wielding-sprung arch -chimney Then again in the late 90s that time I wore out all the k23 bricks from use I also redid the chimney about 7 years ago as it had had it after 3 earthquakes and it was made from leftover stuff-now its all new and tight-the top 15 feet are 12 inch diameter stainless thick wall pipe-I like stainless for stacks it never wears out even on my salt kiln looks as new as the day I put it up. For many years this was fired for over 40-45 glaze loads a year and the same amount of bisques-that adds up as the decades slide by and wears on the refractories.I went thru silicone carbide shelves then dry press high alumina English shelves now for the past 12 years or more Advancers. All my shelves are 12x24s. Average load is 35 shelves. I tried lined fiber on the roof for about 5 years and tore that out and re-sprung the arch with k 26 and k 28s The burners are small 75th btu and I have 8 of them (a pair per burner port) with 4 ports-no safety stuff-all just old school seat of the pants ball valves-no pilots-Just the real deal. I light one set for candling bisque . No computers or ramping just common sense firing-old school-I do have an oxygen probe and digital pyro. on this kiln as well as another but can fire it all with out that stuff in my sleep-after all I fired so many kilns without any of that new tec stuff back in the day its like learning to ride a bike. I do like the extra info and it does make it easier with a kiln like this its very little to do for a fire once its above red heat or in reduction-just watch the cones and turn it off.You are connected to it more than say a computerized electric with auto shut off. Mark Wow, that's pretty prompt construction, it's a lot more complicated than stacking a bunch of bricks :-). You certainly aren't wary of getting right in there and fixing it right up. I'd *love* to to build a permanent kiln somewhere that works well. (I believe the concurrent thread about permitting adequately goes into why not.) It's awesome that you have 8 burners. I imagine it would be hard for them to all blow out at the same time without you noticing. In my experience having an observant and careful person firing and watching a kiln is superior in every way to leaving a kiln unattended with a bunch of safety devices. I'm curious what a truly used up silicon carbide shelf looks like? I just love the process of firing with gas and wood as compared to switching an electric kiln on. It sounds like you have the whole process down so it's like breathing. I still enjoy the dance and the figuring out whether it's going well from moment to moment. A digital pyrometer has really helped me follow how hard I'm pushing my kiln - do you find that having an oxygen probe is significantly more informative than looking at the haziness of the atmosphere inside the kiln? (or when the temperature rise starts to slow down.) Would you recommend getting one? -Lily Link to comment Share on other sites More sharing options...
Mark C. Posted June 28, 2012 Author Report Share Posted June 28, 2012 I'm curious what a truly used up silicon carbide shelf looks like? They look about as curved as a banana and are full of cracks as far as an oxy probe -unless its your living and are doing production I would say no its not worth it-But for me with a glaze load almost weekly it is worth it. What I can tell you is that with a probe you can see the smallest of damper adjustments is a major difference in reduction-We are talking 1/16 of an inch stuff when its in the zone. This is all about reduction firing as thats my life with clay-reduction firing. Mark Link to comment Share on other sites More sharing options...
LilyT Posted June 28, 2012 Report Share Posted June 28, 2012 I'm curious what a truly used up silicon carbide shelf looks like? They look about as curved as a banana and are full of cracks (...) Mark That's so interesting! Does that mean you don't flip your shelves over between firings? So is there any further use for them? Like lining the bottom of a wood fire kiln? I was looking for used silicon carbide at one point to use as an absorption surface for a solar furnace to build with my kids. -Lily Link to comment Share on other sites More sharing options...
Mark C. Posted June 28, 2012 Author Report Share Posted June 28, 2012 I'm curious what a truly used up silicon carbide shelf looks like? They look about as curved as a banana and are full of cracks (...) Mark That's so interesting! Does that mean you don't flip your shelves over between firings? So is there any further use for them? Like lining the bottom of a wood fire kiln? I was looking for used silicon carbide at one point to use as an absorption surface for a solar furnace to build with my kids. -Lily I bust then into small nurds to add 5/8 to 3/4 of an inch when the stilt is to short. when loading Mark Link to comment Share on other sites More sharing options...
LilyT Posted June 28, 2012 Report Share Posted June 28, 2012 I'm curious what a truly used up silicon carbide shelf looks like? They look about as curved as a banana and are full of cracks (...) Mark That's so interesting! Does that mean you don't flip your shelves over between firings? So is there any further use for them? Like lining the bottom of a wood fire kiln? I was looking for used silicon carbide at one point to use as an absorption surface for a solar furnace to build with my kids. -Lily I bust then into small nurds to add 5/8 to 3/4 of an inch when the stilt is to short. when loading Mark How practical. I don't think I've heard the phrase 'nurds' however. Maybe it's too late for my brain to work. -Lily Link to comment Share on other sites More sharing options...
TJR Posted June 28, 2012 Report Share Posted June 28, 2012 The correct technical term is not kiln nurds, but small scrappy, shelf cookies. Anybody else want to weigh in? What do you call your shelf scraps? TJR. Link to comment Share on other sites More sharing options...
Bobg Posted June 28, 2012 Report Share Posted June 28, 2012 Mark, Do you have any picts of your kilns you could post? I'd be interested in seeing them. My brothers a potter also and is moving back to our family farm. I've already talked to him about building a larger kiln. Bobg Link to comment Share on other sites More sharing options...
Mark C. Posted June 29, 2012 Author Report Share Posted June 29, 2012 Heres one http://ceramicartsdaily.org/community/topic/2446-salt-kiln-building/ Mark Link to comment Share on other sites More sharing options...
Mark C. Posted August 1, 2012 Author Report Share Posted August 1, 2012 New batch out this week for Big show a few states away. Link to comment Share on other sites More sharing options...
LilyT Posted August 1, 2012 Report Share Posted August 1, 2012 New batch out this week for Big show a few states away. Geez, those look great. I had been going to get some work done on my computer tonight, but this notification popped up in my email and now I have to keep admiring. $5 is such a deal, no wonder they are snapped up. How many do you think you will sell at this show? -Lily Link to comment Share on other sites More sharing options...
Mark C. Posted August 19, 2012 Author Report Share Posted August 19, 2012 I would hate to have someone get rich on this idea. Just because it works for me it may not for you. Please load safely. Mark Link to comment Share on other sites More sharing options...
btrengove Posted August 21, 2012 Report Share Posted August 21, 2012 Great idea (spoon rest) I have been trying to add a inexpensive "tea bag rest" to my current brand and I have been frustrated with drying times and fussing with for such a "simple" thing. Duh... I forgot about plaster bats. I am also hoping to get my hands on a used slab roller for making "cookies". They are hard to come by in California, what should a used one be listed for? Bev Link to comment Share on other sites More sharing options...
Mark C. Posted March 9, 2014 Author Report Share Posted March 9, 2014 Springtime is spoon rest time again-Been a few years since this post was around-since I'm up firing a few hundred tonight in the glaze fire for a big show in a few weeks I thought I would share again. I think there are a few missing photos as I have dumped some to keep adding new ones and I'm always near or over the limit. As in most things in my life. Mark Link to comment Share on other sites More sharing options...
Babs Posted March 9, 2014 Report Share Posted March 9, 2014 love to see them, Mark Link to comment Share on other sites More sharing options...
Rebekah Krieger Posted March 10, 2014 Report Share Posted March 10, 2014 I don't make a practice of them but I have a rule for myself that if a pot flops, (or If I hate it and want to cut it off the wheel) I make either a pillar candle holder or a spoon rest with the bottom scrap. Yours are nice and have a foot on them. Mine are just flat bottomed and I just trim/round up the edges briefly. Link to comment Share on other sites More sharing options...
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