Archive for Kilns

Five Quick Tips for DIY Repairs

Where Does this Piece Go?

Have you ever been in the middle of a project and forgot where something went?  Have you had extra parts when you were finished?  Have you ever just had no clue where this thing goes that you’re staring at?

These 5 simple tips can be used not only in the studio, but home
repair, and just about any other project you can undertake.

Use a repair or owner’s manual for guidance.

Manuals often have diagrams and detailed instructions to assist with basic repairs. If your kiln did not come with a manual you, can usually find one on-line, or the manufacturer can provided it to you via email. In most cases, the wiring diagram is also available through contact with the kiln’s manufacturer. Again, this applies to most items you may be repairing, not just kilns.

Take a picture.

Use your mobile phone or camera to take a picture of the kiln parts (or whatever you are working on) before disassembling it. This way when you start putting things back together you know exactly where they go. If you need to, take several photos to make sure you can sufficiently see how everything is assembled. Take some photos close up of parts and some of the entire kiln firing assembly to see where wires connect, if you need.

Draw a diagram.

Draw up a schematic that makes sense to you. Use lines with colors and make sure to label all the parts.

Lay the parts out in the order you take them off.

As you disassemble parts of the kiln, lay each piece on a flat, open surface in the order you take them off. Make sure this is an area that will not get disturbed. It may still be a good idea to take a photo or draw a diagram just to make sure you know where all the parts belong. When you are ready to reassemble, just reverse the order in which you took the parts off.

Contact a professional.

Yes, we say this regarding just about everything. But let’s face it,
they usually have the answers we do not. They may also know of a few resources for your continually growing repair knowledge.

You may choose to use one or a combination of these tips. Hopefully they will help to alleviate the headaches associated with reassembling a kiln and not knowing where the parts belong or how they connect. If you are repairing a kiln that you just purchased and not everything is assembled, your best bet is to use an owner’s manual, repair manual, a wiring diagram or to contact a professional if all else fails. Remember stay safe and make sure all power is shut off and disconnected before working on your kiln!

Testing your kiln’s heating elements.

In this post, I hope to shed a little light on how to check the integrity of your heating elements and confirm or rule them out as the problem with your kiln. The heating elements are one of the most likely things to need replaced and one of the easiest to test and replace!

Symptoms of a bad element

There are many symptoms that can lead you to assume your kiln may have a bad heating element. The most common symptoms include an unintended, abnormally long firing or uneven heating throughout the kiln. If your firing takes a significantly longer time and your glazed or bisque pottery comes out unevenly fired in different areas of your kiln, you may have a bad element. Sometimes the kiln may not even reach temp after a very long firing if there is a bad heating element. Another symptom may include the heating element not glowing during firing. If you peek into the kiln and an element isn’t glowing or isn’t glowing as much as the others it is worth testing the element. Just because an element is glowing does not mean it is working properly. After a certain point in the firing everything in the kiln glows due to radiant heat. Whatever you do, NEVER reach into a kiln that is turned on. This could cause severe burns or electrical shock.

Visual Inspection

Before doing anything with the kiln make sure the kiln is completely cooled to room temperature. Next insure the kiln is turned off and the breaker is switched off. Please see our post on electrical safety. From this point the first and easiest thing to do when checking into a problematic kiln is do a visual inspection of the heating elements. First check the inside of the firing chamber. Look for breaks in the element or abnormal coloring. Abnormal coloring could be an indication of a weak spot in the element. If you see a break in the element, replace it. If not, continue reading. After a quick visual inspection inside the firing chamber, check that the element is not broken as it passes through the soft brick.

If all the above seems okay the next step is to take the cover off of the control panel. On some kilns this requires removing the control panel as the control panel is all one part. After unscrewing the cover or control panel the first thing you want to check is the connection of the heating elements to the wiring of the control panel is tightly secured. If this connection is secure you next want to proceed to visually inspect the wiring and connections within the control panel. Look for wear, broken wires, or any burned spots on the wiring connecting the heating elements to the controls and everything else in the kiln. If this all looks okay it is time to get out the multi-meter.

Testing with a multi-meter

To test the heating elements, you will need a multi-meter. These are fairly inexpensive and can be picked up at most any hardware, home improvement, or department store with supplies for home repair or tools. They come in a range of varieties and prices. You really just need a plain, basic multi-meter which should be priced under or around $10.

The meters can be digital or analog.  Digital meters have a dial with a range of settings and a digital readout screen. Analog meters have a needle with several readout levels on them. Either type of meter will work. Before testing the element you need to disconnect the element from everything else. This makes sure that the reading you get is only the resistance on the element and does not include the rest of the circuit.

With the meter, we will test the amount of resistance in the coil. The amount of resistance is measured in Ohms Ω. If you have an analog meter, you will want to read the scale on the meter that says Ω. If you have a digital meter, you will need to set it to 200Ω. Before reading the resistance on the coil you need to zero out the meter by touching the ends of the two leads together. The meter should read zero at this point. Once again the ends of the element should not be attached to anything at this point. Then connect the red lead to one end of the coil and the black lead to the other.

This will produce a reading on the meter.

The reading should be somewhere between 10-30Ω, depending on the element.Check your kiln’s manual for exact specifications. If you don’t have the manual, you can contact the manufacturer. The manufacturer can usually provide you with a copy of the manual, which should specify what the resistance of your particular kilns coils should read. The meter reading should be within a 10% tolerance of the manufacturer recommended resistance. Even if the elements look okay, an element could be underperforming if it reads outside of the 10% tolerance on resistance. That is 10% + OR -.  EXAMPLE: if the manufacturer says 25 Ohms, you should get a reading between 22.5Ω and 27.5Ω.

If you get an infinite resistance reading, this indicates a bad element. Check the manual for your specific meter to see what an infinite resistance reading looks like. If the heating element tests good, the element isn’t your problem and likely lies somewhere in the controls. If the element tests bad, you will need to replace it. To source a new heating element, contact either the manufacturer of your kiln or your local supplier.

If at any point you are in doubt about your abilities, or are outside your comfort zone, don’t hesitate to contact a professional. As always, feel free to contact me with any questions related to this topic.

Want an electric kiln, but don’t have $1500.00 plus to spend?

Is spending less money and buying a used kiln right for you?

This is how I started out! There may be a great solution out there for you. I have purchased several kilns on the cheap and fixed or rebuilt them. There are many things to consider when thinking about buying a used kiln.  Time, money and your knowledge level are good places to start.

Before buying a kiln be sure you know the laws in your area. Some zoning laws do not allow equipment like kilns, especially if you live in a building connected to other residences. Some areas allow kilns but they must be installed by a professional such as an electrician. Some insurance providers, especially the larger ones will not cover properties with kilns installed. Other insurers may cost more than your existing policy but will cover properties with kilns.

Is buying a kiln on the cheap for me?

There are a number of questions you will want ask yourself before jumping head first into buying a kiln at a low price. First, do you know your way around an electric kiln? Do you know how they work and the function of each part?  If you know very little about kilns and how they work you will at least want to do a bit of research, reading up on the different parts and their functions before you think about buying used.  Through some of my future blog posts, I hope to enlighten you more on the workings of these machines we depend so much upon.

As I said above I have purchased several kilns on the cheap.  Some kilns need a lot of love, but are worth the work if you don’t want to spend  a huge sum of money.  Regardless  of  the condition of the kiln you will probably spend  AT LEAST $300-400 on a kiln to include the purchase.  This also depends on the size and condition.  I’m not saying go out and buy a kiln that is complete junk.  Make an educated purchase. Know that you can fix it. Buy a kiln in which the level of repairs needed fit into the zone of repairs you are comfortable making. Working with kilns can be dangerous and should be carefully considered. They use a lot of electricity and could easily cause a fire if not cared for properly.

To give you an example of the complexity of work needed on kiln bought for cheap I will discuss the three kilns I currently own, the condition they were in upon purchase and the repairs needed. I presently own a 27×27″ round, an 18×27″ round and a 17×18″round. All of my kilns are top loaders , with manual controls on the sitters.  I was first given the small kiln while I was in grad school. It had been in storage for a few year but was in working  condition.  This is rare. Very few kilns come in great working order.

As I was in grad school, I quickly outgrew this kiln in a matter of weeks. I was firing almost every day to keep up with bisque and glaze firings. So I then bought  the large kiln. This kiln had been sitting for a few years also. However it had a few more issues than the small kiln. It needed a new coil (heating element), several  relays and  two types of switches. The body of the kiln(floor, brick walls and lid) were not in the greatest condition but they worked. As my knowledge has expanded, I now plan to either gut this kiln and give it new brick (floor, some new wall bricks and a new lid) or I will remove the control panel and install it upon a custom built kiln of my own design.

My middle sized kiln was purchased here, in the UK.  It needed new ceramic fiber in the lid, a new floor, and new switches to control the elements.  Rebuilding  an electric kiln takes time and patience. Most of the time you are not going to get a kiln that works perfect as soon as you get it and hook it up.  Most of the time, kilns being sold for cheap have problems, and many of them.

It can take as many as two to four firings before you get a smooth firing kiln. After hooking up a new-to-you kiln, what usually happens is you let it fire and it will take hours longer than it should.  So then you do a little research  and find the part you will have to replace. Then you will order and install the new part.  Sometimes that will fix the problem. Other times, when the part you first replaced went out, it may have blown out other parts. Don’t be surprised.  This is normal and can get very frustrating, especially if you are on a tight time schedule. Don’t let this deter you.  Kilns only have a limited number of parts that need replacing . As you can see, buying a cheap kiln can be quite time consuming and can get costly. It is often still much cheaper to give an old kiln new life rather than purchasing a new one.

Make sure for the first couple firings that you don’t leave the kiln alone! If you haven’t fired the kiln before you likely don’t know what is wrong with it or what could happen to it during a firing. NEVER trust a kiln you buy used until you have fired it several times and know it is working properly. You may not know the previous owners knowledge level of kiln repair. So again please take caution when firing a new-to-you kiln.

Where to buy a new-to-you kiln.

There are many places to buy used kilns. I have used eBay and Craigslist. Both are equally viable choices.  Local and regional pottery and ceramics organizations usually have classified ad postings and message boards with loads of listings. If all else fails, you can always just do searches on any search engine for used kilns for sale. The cheapest way in my experience, seems to be eBay.

If you decide to buy a fixer-upper kiln…

Make sure you look at the pictures, read the description, ask any questions you may have and know what type of electrical requirements are necessary for the kiln you are looking at. If you will be hooking the kiln up to residential wiring, make sure you have the appropriate electrical service coming into the property.  Electric kilns can require several different levels of voltage. Usually this can be wired in from the pole by the electrical company if your residence does not have the proper voltage supply. Make sure to check with your power company before buying a kiln that does not have the right voltage supply for your residence.

Make an educated decision.  Do not go into buying a kiln blindly. Buy a kiln that requires work at a level you are comfortable doing. Please always remember safety first. If you are dealing with kilns please read our post on electrical safety and if ever you’re even a little uncomfortable with doing the work yourself, don’t hesitate to call a professional.

Electrical Safety for Ceramists

Q:What is the definition of a shock absorber?     A: A careless electrician!

All jokes aside, electricity is a very powerful thing and we should take it very seriously. Electrical shorts can cause fires and contact with electrical current can cause burns, shock and even death.  It only takes about 100mA to cause irregularities in the rhythm of the heart that will obstruct blood flow and kill a person.  The kiln Jessica currently uses is capable of drawing around 30A. That’s 300 times the lethal dose if it manages to go through the heart! Most of the equipment the average ceramist uses draws much less current but still carries enough punch to be just as dangerous.

Let’s start out with some general guidelines for working with electricity:

  • Keep all cables and power sources away from water and moisture
  • Keep electrical devices away from flammable and explosive materials
  • Use only cords and connectors rated for the electrical loads they will support
  • Don’t “daisy chain” cords or connect too many to one outlet
  • Don’t use equipment with exposed or frayed wires
  • Avoid putting too much stress on cords and cables, or folding them over
  • Always make sure cables are out of the way or visible if they must be in the open
  • Never carry tools or equipment by the cord
  • If possible, disconnect equipment from the power source when not in use
  • Make sure there is no power to any device before working with its internal wiring

Without going into specifics like “don’t poke metal forks into electrical sockets,” the above list is fairly complete for those who’ve operated a light switch recently.  What we need to keep in mind in the ceramics community is that an overwhelming majority of us use some pretty heavy duty equipment.  Many of our tools of the trade require a bit of added attention.  The kiln mentioned above, for instance.

Electric kilns probably require more power than any other piece of equipment in your studio. This fact alone means they’ll need a little more attention on the electrical side than your other equipment.  But where to start?

Power Source.  Make sure you have the right kind of power coming into your kiln space.  There is a huge difference between the common voltages used for kilns.  120V, 208V, 240V, and 400V all require different types of wiring and connectors.  If you’re unsure of how to judge the right wiring and connectors for your kiln, call a qualified electrician.

Circuit Breakers and Fuses.  You’ll need to make sure your kiln doesn’t fry the rest of the wiring to your home or business.  Most modernized buildings will have a breaker box and this is the recommended way to go.  Not only do you not have to replace burnt fuses, they’re safer to use.  Make sure your breaker or fuse has the proper rating for your kiln.  Consult your owner’s manual for the needed current.  This will be rated in Amps.

Wiring and Connectors.  Like breakers and fuses, wiring and connectors are also rated in Amps.  Unlike the breakers and fuses though, it’s recommended you get cables and connectors rated for above the current requirement.  This will prolong their lifespan and help to avoid burning them up, should a surge occur.  Make sure all junction boxes are rated for at least the same as the wiring and all connections are tight and secure.

Isolator Switch.  In my opinion, this is one of the most important parts of getting power safely to your kiln.  You’ve probably seen them on industrial equipment. You can mount this on the wall near you kiln and connect the kiln directly to it.  It will work as a power switch and an additional breaker.  It’s just one more safety feature in the line and they can even be found with a pad lock feature to make sure they stay in the off position when not in use.

Internal Connections.  While Jess and I always recommend inexperienced owners have a qualified technician check the internals of your kiln at regular intervals, we understand that many people will want to do their own repairs.  That is, after all a focus of may of our blog posts.  If you’re going to open your kiln yourself, make sure all connections are tight and none of the wires are  damaged or appear to be shorting to the metal.  This will be covered more in depth in a future post.

Heat is the Enemy.  If you notice any abnormally warm wires or connections, don’t risk it.  Turn off power at the breaker and find the problem.  You may have bad wiring, a loose connection or could be drawing more current than your wiring is rated for.  If you need help, don’t hesitate to call a qualified electrician.

On a related note, insurers and law makers know the risks involved with owning and operating a kiln.  Make sure to check with your insurance company to make sure they’ll insure a home or business with a kiln.  You may need to switch insurance companies to use your kiln.  Some locations will also have local regulations stating where these types of equipment can be used and how they have to be set up.  Your best bet is to call the city or county engineer to make sure you’re clear on any existing regulations.

This is not intended to be an all-inclusive reference and is meant only for general guidelines.   There are plenty of great resources out there in books and courses to get your more familiar with electrical safety.  If you’re going to be working on your own equipment and wiring, I highly recommend you consult some of these resources and professionals in the field.  Professional electricians and qualified kiln repair technicians are typically quite proud of their skill-sets and are usually more than happy to let you look over their shoulder as they do their job.