FrogBlog
Kilns vs. Ovens vs. Furnaces | What's the Difference
When choosing a heating method for hardening, curing, or transforming your projects, kilns, ovens, and furnaces are all important options. So, what’s the difference between these three terms and how different are they?
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Understanding Kiln Relays: For New Kiln Buyers and Owners
Ah, the timeless query of kiln shopping: "Which kiln relays should I go for?" It's like asking a chef for their salt preference – important, but let's not get too salty about it. Kiln relays are like the Elon Musk of the kiln world – well-known but often misunderstood. If you're scratching your head wondering about relays, don't fret. This article will shed light on the topic, enlighten you, and make you wonder how you ever survived without this knowledge. Your kiln's relays are the VIPs of the whole kiln operation. Treat them right, and they'll keep your artistic dreams alive. Neglect them, and you'll end up with a sad, cold kiln. So, let's grasp the basics of relays, so we can discuss relay care and maintenance. What are kiln relays, and how do they work? A kiln relay functions as a gatekeeper, regulating the electric current in a kiln. When a relay is closed, it allows energy to flow to the kiln's heating elements, making them hotter. Conversely, when the relay is open, the circuit is interrupted, and no electricity reaches the coils, resulting in no heat. Larger kilns are equipped with multiple relays, each controlling a specific area. Imagine relays as bouncers at a nightclub. They ensure things don't get too hot with an overcrowded club. They let in just enough people to heat up the action, then close the door to maintain the perfect temperature. When things cool down, the relay receives the signal to allow more people onto the dance floor (the element), restarting the cycle. That clicking sound your kiln makes during firing? It's the mechanical relays cycling on and off, akin to a bouncer opening and closing the club door to maintain the desired temperature. What are the different types of kiln relays, and how do they differ in function and longevity? Just imagine you're cruising down the highway, wind in your hair, not a care in the world because you never have to change your car's tires! No more struggling with lug nuts or getting your hands dirty. Ah, the relaxing feeling of never having to deal with a flat tire or the dreaded tire store. It's like winning the lottery, but without the money or the fame. Mercury and solid-state relays are kind of like that, they're the choose-it and forget-it component of your kiln that you'll never be sorry you chose. Mechanical relays are like the candles on a birthday cake - they have a limited lifespan and eventually need to be replaced. They'll last you about as long as a Kardashian marriage, so make sure to cherish every click. There are three main types of kiln relays: 1. Mercury relays: These use a tube of mercury with an internal weight that determines whether the mercury rises to complete the electrical contact. With fewer moving parts, mercury relays have an impressively long functional life, typically lasting around 5 million cycles. They are nearly indestructible, but due to mercury disposal concerns, some states no longer allow their use. 2. Solid-State relays: Operating with power semiconductor devices, solid-state relays have no moving parts. They control the flow of electricity by opening and closing. Due to their lack of moving parts, these relays boast an exceptionally long functional life, said to surpass 1000 years! They offer tighter temperature controls because they cycle faster, which is also said to save energy. 3. Mechanical relays: These relays utilize electric current to move a contact, either opening or closing the circuit using an electromagnetic switch. Mechanical relays do have moving parts and because of that they have a limited lifespan. On average, they last around 200,000 cycles (clicks), which translates to approximately 18-36 months, depending on usage, firing temperatures, and schedules. Why is it crucial to monitor the health of kiln relays? Imagine if your trusty relay suddenly called it quits. It's either going to be a hot mess or a complete blackout. If the relay stays open, you'll be left with a cold and useless kiln – no heat for you! On the other hand, if it fails in the closed position, get ready for an intense blast of unending heat. Neglecting to monitor your mechanical relays can turn your project into a disaster, leading to kiln meltdowns or accidental kiln damage. While larger kilns with multiple relays offer some backup, you'll still sense that something has gone awry. When should you replace your kiln Relays? Now, let's address the million-dollar question: When should you replace your kiln relays? Well, imagine your relays belting out Whitney Houston's "I Will Always Love You." That's your cue to bid them farewell! The lifespan of your relays depends on their type. If you have mercury or solid-state relays, consider them ageless wonders that can last the entire lifespan of your kiln, just like Rob Lowe's ever-youthful career or the timeless elegance of Jane Fonda, or even Cher. They just don't age! A periodic visual inspection should suffice to ensure their good health. However, if you're rocking a mechanical kiln relay, it's a different story. These relays have moving parts, which means they eventually wear out like a neglected houseplant. On average, you can expect them to last around 18 to 36 months. Of course, usage, firing temperatures, and firing schedules play a role, so it's best to replace them every 18-24 months as a precautionary measure. Luckily, some kiln manufacturers have added nifty features to make relay monitoring easier. Jen-Ken Kilns has installed a "pilot light" on every relay of every model. It's like having your own personal relay detective! If the light stays dark when the relay fires, you know there's a problem with the element, relay, or connection. Evenheat Kilns introduced a relay access door, a secret passage to a world of wires and switches. It's a magical portal that saves your fingers from untangling wires like a hopeless spaghetti chef. When it's time to replace a relay: Be sure to check for heat damage on the old relay. Look for melted spots in the plastic body, indicating excessive heat. In such cases, replace the push-on terminal of the wire connected to the relay before installing the new one. Loose terminals can wreak havoc on the new relay, as they generate excessive heat and compromise performance. Remember, a well-maintained kiln with healthy relays will keep your creative projects on track. So, embrace the kiln relay journey, have some fun with it, and keep those artistic dreams alive. And hey, who knew kiln relays could be so entertaining? Now go forth and conquer the world of kiln-firing with your newfound relay knowledge! For more information on kiln relays and replacing them, check out these resources from our trusted manufacturers: Evenheat Kilns: Relay Replacement via Access Port Showcase Paragon Kilns: Relay Replacement Guide and YouTube video. Olympic Kilns: Relay Replacement Guide Jen-Ken Kilns: Small Relay and Large Relay So, there you have it! Kiln relays may seem like hidden heroes, but they play a vital role in the success of your creations. Understanding their purpose, types, and lifespan is key to maintaining a well-functioning kiln. Remember to regularly inspect your relays, replace them when necessary, and keep an eye out for any signs of heat damage. Now, armed with this newfound knowledge, you can confidently embark on your kiln-firing adventures. Whether you're a seasoned artist or just starting out, the dance between you and your kiln relays will be one of artistry, precision, and, most importantly, creativity. So, turn up the heat, let the kiln roar, and let your imagination run wild as you create beautiful ceramic pieces with the assistance of your trusty kiln relays. Happy firing! Need to order replacement relays? This form can help!Or if you know what you need, here is a link to order mechanical relays If you have any more questions or need further assistance, feel free to ask. You can talk to a real person on the phone immediately (361-596-3764), or via instant chat (click here to start a chat now), email (customerservice@kilnfrog.com) or via real time texting (361-596-3764) - you choose! (We promise we will respond during regular business hours.) Enjoy your artistic journey!
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Bullseye Glass Index of Frequently Asked Questions
Do you have exploring questions about Bullseye Glass and how to use it? Their Index of Frequently Asked Questions can be a helpful guide! It contains anything and everything you ever wanted to know about Bullseye Glass. So, get comfortable... this is a TON of great information! GENERAL Is Bullseye glass COE 90? Can I use a ceramic kiln for glass? How can I learn to cut glass? Is Bullseye glass compatible in all conditions? Is Bullseye glass food safe? What are "striking" glass colors? What should I know about studio safety? What's the specific gravity of Bullseye? How do I know which clear Bullseye glass to use? Is there bubble-free glass? Why should I choose Bullseye glass over other glasses? New to using Bullseye Glass? COLDWORKING What is coldworking? Besides sandblasting, how can I remove devit? Can I sandblast glass to remove devit? How do I coldwork my kilncast piece? How do I get rid of sharp edges on my project? KILNFORMING What is kilnforming? How and why should I clean glass before firing it? How do I prevent glass from sticking to kiln shelves? How do I restrain glass flow? What is annealing? Why is it necessary? What is devitrification or devit? What is firepolishing? What is fusing? What is slumping? What is tack-fusing? What schedule should I use for annealing? Why should I fuse and slump glass in separate firings? Want to see the full list? Check it out here... Index of Frequently Asked Questions!
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Hunting for a Dead Short in a Kiln
This post was written by Arnold Howard, a former employee at Paragon Industries who is now an independent kiln technician at Howard Kiln Services. The owner of a Paragon A-24B called to tell me he saw sparks flash inside the switch box on his kiln, and the circuit breaker tripped. He could see the flash through the ventilation louvers on the side of the box. “It made a loud noise that scared the hell out of me,” he said. “It happened when I turned the bottom switch to high.” “Your kiln has a dead short,” I told him. A dead short causes a large amount of electricity to flow suddenly through the wires. This shuts off the circuit breaker for your kiln because the surge of electricity is much greater than the amperage rating of the circuit breaker. A dead short usually happens when the protective insulation on a wire has been damaged, and the bare wire touches either another wire, an element connector, or the steel case of the kiln. After arriving at the customer's home, the first thing I did was open the switch box by removing hex-head screws with a 1/4” nut driver. The screws are on the sides of the switch box of most kilns. You can buy the 1/4” nut driver from a hardware store. Some brands of kilns require a different size nut driver. If the size you need is not available locally, you can order one online. This may be the case overseas as the 1/4” size is uncommon there. Remember, always BE SAFE! If you ever remove the switch box on your kiln, first unplug the kiln. This is essential because otherwise you will be exposed to live wires inside the opened box. In the first photo, you can see the element connectors, which are small brass barrels with a screw-on each end. Notice that a wire is attached to each connector. In the A-24B, those wires go to switches. In digital kilns, the wires go to relays, which turn the elements on and off. Lying on the garage floor, under the shadow of my lamplight, I hunted for the dead short. Since the sparks flashed when the bottom switch was turned to high, I started my search at the bottom of the switch box. In the second photo, you can see where the short occurred. Look at the element connector in the bottom center half of the photo. It is the blackened brass barrel that is against a white porcelain insulator. The element connectors are the hottest items in the switch box. If a wire touches an element connector, the insulation on the wire can eventually burn off and cause a dead short. In the bottom right corner of the photo is a red wire with a burned spot. That burned spot is where the wire touched the element connector. The spark blackened the connector. With any routine kiln maintenance, you or your kiln technician will need to open the switch box or protective cover panel on your kiln if you ever change a thermocouple, relay, switch, or repair a damaged wire. As you can see from the photos, it is important that as you reinstall the switch box or panel onto the kiln, check that the wires will not touch an element connector. To be sure that the wires would not touch element connectors or the kiln case, I looked at the wires from the side while closing the switch box, tucking some of the wires out of the way inside the box. Then I carefully positioned the switch box on the kiln and installed the screws. You might want to shine a flashlight into ventilation slots or louvers to check the position of the wires one last time after you have reinstalled the switch box. As you can see from this story, major kiln problems can be avoided by taking just a moment to check the small details whenever anyone works on your kiln. Thanks, Arnold!
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Sweet Dotted Bowls
Bullseye Glass Quick Tip: In this Quick Tip, learn how to make these sweet dotted bowls with Color Line Paints and the simplest of tools! To get started, layer two 4.75 ̋ circles of colorful 3mm sheet combinations and fire to a full fuse. For a slightly thinner, lighter bowl, swap the top 3mm layer for thin (-0050). The thinner top layer will contract just enough to form a narrow border of the base color along the bowl’s rim. Once your blanks are ready, let the fun begin! Using pins, toothpicks, and Color Line’s affixable tips, add dots and flourishes of Color Line Paint in organic patterns. Explore the diversity of colors and the bold-to-whimsical mark-making range that these ready-to-use, lead-free enamels make possible. Easily mixable, they’re also great for developing your own custom colors. Fuse the Color Line enamels to a gloss by firing the painted blanks, then slump in a Ball Surface mold (firing schedules below). Firing Color Line reds often requires a little extra attention.
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Is it time to change your mechanical relays?
It seems like every November we get the same phone calls and the same e-mails... "My kiln has stopped working and I have a show this weekend. Please HELP!" With that in mind, it's important to remember... owning a kiln is like being a Boy Scout, it's important to always BE PREPARED! Murphy's law says that whenever you need your kiln most and are firing the most, that's just when it's going to have a problem. So.... we all know that an ounce of prevention is worth a pound of I told you so. This is not directed to any one of our clients who've contacted us this month with an OMG moment! This is for all of us, who are just very busy and forget to take care of the basics. And yes... this has happened to me so, you're not alone. If you don’t already know, a relay is the part of the kiln that controls the power or current to the element, allowing the element to either receive current and get hot, or to interrupt the circuit thus not allowing the element to receive current and cool down. The mechanical relays, which come standard on most kilns, are what is responsible for the ubiquitous opening and closing clicking we hear while our kilns run. ALL MECHANICAL RELAYS in U.S. kilns are virtually the same... no matter the manufacturer. Mechanical kiln relays have a life of up to “X” amount of clicks and then they fail. This failure can either be in the closed position (Yikes, my kiln temperature keeps rising and it won’t turn off… everything is ruined!”) or they can fail in the open position. (Yikes, my kiln won’t heat up at all!) If they fail, it is not the manufacturer's fault, since they do not make the relays. They test them to make sure they work at the factory, but after that... it is your responsibility. We know that all failures stink and that is why we recommend changing your relays every 12-24 months. If you are a heavy kiln user, you should be smart and change your relays once a year. Think about it like an oil change or new tires... you wouldn't let your car drive on bald tires or your engine run on old oil. Pick a month and make it kiln maintenance month. Install new relays, paint the bottom with kiln wash, etc. and give your kiln a thorough inspection. Don't be the cautionary tale!! Finally, if this is something you don't want to hassle with... you can eliminate the problem by upgrading to mercury or solid state relays and almost never have to change a relay again. In our opinion, it's the best upgrade money can buy. With mercury relays it is important to make sure that regulations in your area don't prohibit them. The following states have prohibited the import of Mercury Displacement Relays within their jurisdictions: CA, CT, RI, IL, NH, MA, MN, ME, VT, NY, LA, MD, WI. If mercury relays are not for you, many kilns come with the option to add solid state relays for an additional charge. Hot Shot takes it one step further and makes all kilns with solid state relays by default.
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Why is my Kiln or Oven Not Heating Properly?
Let's be honest... using a kiln comes with its share of emotional ups and downs.
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