An Amaco authorized kiln repairman, Rogier has been maintaining and repairing kilns for over forty-five years. His clients include the Indianapolis Public Schools, the Vigo County School Corporation, the Northeast School Corporation, the South Vermillion School Corporation, the Southwest School Corporation, as well as numerous other school corporations in the Midwest. Should your school's kiln be broken or need attention, please do not hesitate to make use of the "800" number below or send Rogier an E-mail with all the pertinent kiln information. On Amaco kilns all the important numbers and information are stamped in the metal nameplate on the side of the kiln. Model number, serial number, Voltage and Phase. When you do call, have all that information handy. Just in case you read this in "Timbuktu" and to save on the "800" number phone bill, please realize that Rogier travels mostly in Indiana and border areas of neighboring states. A service call to California or Maryland just would not be cost effective :-) So, if you live in the Midwest and have a kiln problem go ahead and make that call or send that E-mail. Rogier will be happy to discuss your needs and quote you a realistic and honest evaluation!
1-800-394-2289
Click here to see the "About that melt down...."
Observe the beauty of the over-fired mass…
L
Anybody who’s ever fired a kiln knows the sickening feeling one gets when first opening a kiln and one is confronted with the above. While the molten lava often has beautiful colors and flow patterns it is a sad tale indeed to have to tell your students that their master pieces were reduced to a molten mass. Most schools use earthenware clay that has a maturing temperature of around 1850 degrees and a melting point of around 2000 degrees. When pieces are glazed and the kiln is over-fired the glaze has a tendency to act as a flux and lowers the melting/flow point of the clay. Most school kilns can attain a temperature of 2350 degrees; if the kiln load consists of earthenware and the kiln is left “on” beyond the maturing temperature of the clay (around 1850) there will be a problem. As is obvious in the above pictures the kiln over-fired, but why, wha’happened? In this particular case, as near as I can tell, there was an explosion in the kiln. Those things occur, but what a lot of people are not aware of is that when there is an explosion, all kinds of things can and will happen: the explosion causes a zillion tiny clay/glaze particles and smithereens to float around in the kiln atmosphere. In time these particles and larger smithereens land on the shelves, on other pieces, in the element grooves and sometimes on the kiln sitter tube assembly. As the kiln gets hotter and hotter those small particles of clay and glaze melt. Attached to something like the cone supports and or the kiln sitter tube these now molten particles fuse the cone, the cone supports and the kiln sitter rod in one big molten mass causing the kiln sitter to be inoperative. The timer on a kiln sitter is supposed to be a back up to turn the kiln off should the cone not do so. It is crucial that the timer is set to turn the kiln off minutes after the cone was supposed to. Keeping a kiln log will show you that the interval between cone cut-off and timer cut-off can be reduced to as little as five minutes. During which time nothing serious in terms of an over-firing will happen. Should the timer not have been set correctly and there is lots of time on the timer the kiln will just keep going until the timer runs out of time or the elements short out… In the above case the teacher was very fortunate that there was only a couple of hours left on the timer which shut the kiln off before it was totally ruined. As it was a few wall sections had to be replaced as well as all the kiln furniture. By necessity all the elements and the kiln sitter tube assembly also had to be replaced, but when it was all over the repair was still a lot cheaper than a new kiln!
There’s a lesson here – you knew there’d be one, didn’t you?
Kilns are among the most expensive pieces of equipment in the art room. Should you not know how to properly operate the kiln or how to properly set the timer on the kiln sitter, I urge you to get a copy of my instruction manual. Please! Your administration will be grateful!
Lesson # 2
Never, I repeat, never leave the kiln un-attended!
The above does not mean that you have to sit in front of the kiln for the duration of the firing. It does mean that once you figured out (via that kiln log!) when the firing is supposed to be done you be there! So you can turn off the kiln should for some reason the kiln sitter does not do its job. It cannot be over-emphasized that keeping a kiln log and getting to know your kiln is of the utmost importance and really, when you come right down to it, it does not take very long to get to know the characteristics of your kiln. Firing a kiln is not rocket science and common sense goes a long way to understanding that toaster oven on steroids!. Should you, after reading the manual still have some concerns, don’t hesitate to contact me. I’ll be glad to help!
By now everyone knows that I’ve been around kilns for a while. It never ceases to amaze me how little those who are trained to teach the next generation know about firing kilns… This being MY web site and being an opinionated sort of guy I can spout off a little. Again! ;-)
The other day I was called upon to repair an Amaco AH 25SF. Smaller cousin to the AH 30SF, the “25” is on of the larger front loaders. Like most Amaco kilns this model too carries a five-year warranty and is one of the more popular school kilns. As is the case with the AH 30, the “25” has elements in the floor. Highly recommended by the factory and “those in the know” (like yours truly…) operators are encouraged to place a false bottom on top of 1” shelf supports on the floor of the kiln to protect the elements from possible explosions and the resulting “smithereens”. Now everyone knows that “explosions” happen, either because the kiln is fired too fast, or the ware in the kiln was not quite dry when the firing cycle began… It is one thing to have explosions, quite another thing to not realize that the resulting debris and smithereens need to be cleaned out…. The kiln pictured below suffered multiple explosions. At no time were the smithereens vacuumed out. As a result the bottom element grooves filled up with glaze and clay particles. So many explosions took place and so many smithereens were the result that the element grooves filled up to the point of embedding the element coil in lava… Each subsequent firing resulted in more melting and re-melting of the lava and it should be considered a miracle that the heavy-duty elements lasted two years before giving up the ghost… Warranty does NOT cover this blatant kind of disregard of basic house keeping rules and operating guidelines! Good thing Amaco is such a nice company to do business with! Amaco kilns are built to withstand abuse and they can be repaired to top notch “as new condition”. It would of course be better if the universities did a better job of training our future teachers in the correct operating procedures of these very expensive pieces of equipment! The AH 25 retails for “only” $ 5495.00 and like all AH or HF Amaco kilns has a lifespan of forty to fifty years IF PROPERLY TAKEN CARE OFF! Ah well, as I mentioned earlier, things like this keep me in business… It took some doing, but once the floor brick and all the lava was chiseled out, and the floor was rebuilt with new brick and new bottom elements, were installed the kiln was like new again. As part of the repair, the operators also received a “mouthful” as well as a copy of the manual “Of Clay, Glazes and Kilns” in which basic operating procedures and a few other bits and pieces of information are discussed. To purchase YOUR copy of “Of Clay, Glazes and Kilns” please hit the link on the opening page of the web site.
1-800-394-2289
The “Cadillac “of the Amaco line of kilns, pictured above is an AH 30 that was over-fired. After all the lava was removed and the brick work repaired, new element holders and elements were installed and even though this particular kiln was already 27 years old when it was repaired a few years ago, it will serve the school corporation for many more years. I’ve worked on HF 97’s, HF 101’s and HF 105’s that were going on thirty years old and were still doing just fine, thank you.
The most popular school kiln is the Amaco HF 97. These so called "box" kilns are far superior to the round or octagonal "hobby" kilns. Amaco kilns are heavily insulated (unlike most hobby kilns) and easily have a life span of thirty, forty even fifty years. The oldest Amaco kiln I ever worked on was an AH 10 front loader that was fifty-four years old at the time (1997) that I repaired it. To the best of my knowledge it is STILL working! The HF 97 top loader pictured above was eight years old at the time, was slightly over fired a few years earlier, but still worked fine. Recently it was moved and sustained quite a bit of additional brick damage. All the elements were broken. The kiln was rebuilt with new brick and new elements at a cost of under HALF the replacement cost ($ 4000.00) of a new one. It is quite acceptable and normal to rebuild a box kiln especially if the metal work is still in good shape. Rebuilding doors/lids is also quite common.
1-800-394-2289
Amaco box kilns are superior to most other kinds of kilns. That, in my humble opinion is a given! Given the economy and shrinking budgets, school corporations find themselves having to economize and cut back in various departments. Art departments are among the first to suffer from a downsized economy. In recent years so-called “hobby” kilns have become quite popular, mainly because of their initial purchase price. Like their “bigger-‘n-better” box kilns cousins these hobby kilns can be repaired, but a lot of times the cost of the service call, the higher cost of parts and the basic “nature of the beast” make repairing them almost cost prohibitive. That is not to say they cannot be fixed – I’ve seen ten-year-old hobby kilns in a school setting that were well maintained and still going strong. In those cases the operators educated themselves and were not afraid to tackle repair problems. More power to those unnamed heroes! Should you have a problem with the hobby kiln in your art room please do not hesitate to E-mail me. In a lot of cases I can talk you through the repair, if you are willing to tackle the job! If you are not – I’ll come running! J
I’ve been working on kilns and been around art teachers for a bit and every once in a while I am thoroughly amazed at the…well …you can fill in my choice of words here yourself. Here’s a sad tale about a perfectly good kiln suffering a totally unnecessary over-firing:
Got a phone call from a school administrator the other day. Could I please come and check out their kiln. It seemed to have over fired. So I hopped in the Suburban and drove 240 miles to check the kiln out. A twenty-year-old HF 105 equipped with a kiln sitter with limit timer. Over fired all right…imagine my surprise when I saw why it had over fired…First of all the timer had not been properly calculated to back up the melting of the Junior cone and secondly the veteran art teacher, who should have known better, had used a full size large cone in the kiln sitter tube assembly…. The picture below shows what it looked like! The good folks at Orton (makers of the ceramic cones) as well as yours truly have been telling the art populace for years NOT to EVER do that! In the picture you can clearly see how the weight of the large cone is responsible for NOT letting the cone rod down enough to kick off the kiln sitter…. I TOLD YOU NOT TO DO THAT! Should you not know the formula to calculate the timer of the kiln sitter in relation to the kiln temperature may be you should get a copy of my manual! Even though both the junior cone and the standard size cone are marked the same (05, 06 or whatever) they behave quite differently when used in a kiln sitter tube assembly. It is NEVER a good idea to use a large cone in a kiln sitter tube assembly. There are those who would argue with me and say that it is all right to break off the tip of a large cone and use it instead of a junior cone…HEY! How much does a box of little cones cost? Of course if you insist on using large cones, go right ahead, your malpractice keeps me in business! Pictured below is a mock up of the cone that I salvaged out of the over fired HF105. One can clearly see how the weight of the large cone “body” prevents the downward travel of the cone rod. It would take a few more hours for the tip of the cone to really melt and then of course it would be too late... The other picture shows the proper way to install a junior cone in a kiln sitter tube assembly.
Have a kiln problem? Help is a phone call or E-mail away!
1-800-394-2289