14 January 2018

Firing a Kiln in Cold Weather

From the bomb cyclone that many experienced last week to colder than average temps across Texas, this unusual winter weather sweeping across North America is causing havoc for everyone! So, with snow swirling outside and the wind howling, this question frequently comes to mind... can you fire a kiln in an unheated basement, shed or garage?

A few years ago, Arnold Howard from Paragon told us about a customer who tried to fire a digital kiln in a garage where the temperature was 30°F. The digital controller display locked at 32 degrees, and she could not clear it. After the weather warmed up, the kiln started working again.

Most digital controllers can register temperatures of –300°F; however, the circuit boards are designed to operate in temperatures no colder than 32°F. Temperatures lower than that can cause the controllers to malfunction. For example, the TCR message ordinarily means the thermocouple leads are reversed, but it can also appear when the thermocouple inside the kiln is much colder than the controller circuit board.

In spite of this, it's definitely possible to store and fire a kiln in an unheated building in cold or freezing weather. Gail had her larger kilns in the garage for years prior to building her new studio. For storage, you must make an extra effort to keep moisture, such as the air from a dryer vent, away from the kiln to avoid the formation of frost on the metal jacket. When it comes to firing, it's important to first raise the room or ambient temperature to 32°F. This can easily be done with am inexpensive space heater. Just place it within a couple of feet of the control panel before you start your kiln and let it run for an hour or so. After you turn on the kiln and it begins to heat, you can turn off the space heater.

Moisture that the firebricks have absorbed from humidity will burn off harmlessly so long as the kiln is vented. Keep the lid in the vented position until steam no longer fogs a mirror, or run a motorized downdraft vent.

Stay Warm!

06 January 2018

Kiln and Oven Troubleshooting

Happy New Year ! After reading dozens of "I am so excited for my new kiln" posts, I thought I would share some Kiln and Oven Troubleshooting advice that I got from our friends at Evenheat Kilns.

Brick Cracking and Hairline Cracks
Hairline cracks are common in all kilns and should not be a concern. Bricks expand and contract when heated and then cooled. The cracks will close as the kiln gets hotter. This is most prevalent in the kiln top or bottom.

Kilns fired at the higher temperatures will experience more spalling and cracking of the brick. Kilns cooled down too rapidly will effect the amount of cracking. If you are repairing a broken brick, repair cement should be used to adhere the broken piece back into place. If a brick breaks under an element and is impossible to repair, an element pin can be used under the coil to prevent drooping.

Fuse "Blows" or Breaker Trips Immediately when Kiln is Turned On
Generally speaking, if a fuse "blows" or circuit breaker trips immediately upon applying power to the kiln, or pressing the start keys, it indicates a short circuit within the kiln itself. It's also possible that the fuses or breakers protecting the circuit are not sized properly. Check the wiring for any signs of arcing (visual and smell). If there is any evidence of arcing, call a qualified electrician to fix the problem. This must be fixed before you continue firing.

Another cause of this issue, is that the electrical service to the kiln is wired incorrectly. Have a qualified electrician check the electrical service from the main service to the kiln. There have been incidences where the connections from the electrical pole outside to the main service at the house has been loose. Finally, it could be as simple as the circuit is overloaded. The easy remedy to this is just disconnect all other appliances on that circuit while operating your kiln.

Fuse "Blows" or Breaker Trips During Firing
Generally speaking, if a fuse "blows" or circuit breaker trips sometime after the beginning of the firing it indicates a problem with the electrical service itself. The causes are varied. Heat at the fuses or breakers will cause them to "blow" or trip at lower amperage levels. This heat can be caused by a weak or loose connection at the fuse or breaker or elsewhere in the service (heat travels well in copper). A fuse or breaker is not normally warm or hot. It should be very close to room temperature during normal operation.

It's possible also that the fuses or breakers are bad, weak, junk etc. Replace only with the proper size. Do not install larger fuses or breakers to solve this problem. Something out of the ordinary made the originals fail. The problem must be corrected not bullied into submission. It doesn't work that way. In this type of situation, it is suggested that a qualified electrician be asked to check for circuit problems.

Be Smart. Be Careful. Have Fun!

17 December 2017

The Importance of Keeping a Firing Log

In 1905 Spanish philosopher George Santayana wrote these well-known words “Those who cannot remember the past are condemned to repeat it.” And, for anyone that uses a kiln on a regular basis that quote can have significant meaning.

That is why we recommend that EVERYONE keep a firing or project log. We cannot stress this enough as it is the easiest ways to learn about your kiln and recall exactly what glass, metals, materials, molds, and most importantly, firing schedule you used. Over time, a properly kept log is critical to keeping track of what you’ve done. It will help you learn the particulars of your kiln plus it will go a long way towards avoiding future mistakes.

In many ways, a firing or project log is the most underappreciated tool in your studio. All too often, the enthusiasm to fire overcomes the need to keep records of the firing, resulting in unusable comments. This is an enormous mistake. The firing or project log is one of the most essential tools you have. The combination of your kiln, the materials you select, and the designs you create are exclusive to you. No one else can precisely duplicate the conditions in your kiln, so it’s up to you to keep records that are detailed enough to allow you to repeat good firings and avoid repeating bad ones.

     

Some people suggest that a printed log like the Bullseye Kiln-Glass Project Notes, the Paragon Ramp-Hold Firing Record or the Joy of Fusing Project Log, while others favor a simple notebook. Digital logs are also a popular option.

It really doesn't matter which log you chose as long as you document, document, document!  Some firings will require minimal notes while others might demand several paragraphs, pictures and/or sketches. Most importantly, keep you log in your work area. Use it religiously and enter essential information about each firing.

As you become more knowledgeable, you may find that many of your firings are similar and require minimal entries. But regardless of your experience level, don't stop logging your firings, as your log is a priceless tool!

10 December 2017

The holidays are coming — break out the punch! (The paper punch, that is)

Bullseye Glass Quick Tip:

In this Quick Tip, you will learn how to combine punched silver foil design elements with Tomato Red Opalescent for something truly festive just in time for the holidays!

Silver, in the form of thin sheets, can be fired with glass in the kiln to produce a palette of effects, ranging from subtle to dramatic. We just love the variety of effects you can get!

Keep in mind, when working with foil that sometimes it can be a real pain as it's super thin and likes to stick to everything. So, before punching out shapes or cutting them with scissors, take the extra time to sandwich the silver foil between sheets of paper. This creates a toothy structure that cuts cleanly and keeps the foil from tearing. 

Bullseye Kiln-glass Education Online also has a great video lesson if you want to learn more about Using Foils with Kiln-Glass.

Enjoy the punch!

03 December 2017

Increasing the Life of your Firebrick Kiln

Throughout the years, we have seen 10+ year old kilns with firebricks that are still in pristine condition and relatively new kilns that looked like they had been dropped from a three-story roof. It's pretty easy to tell when a kiln has been cared for and given that extra level of TLC or, what we like to call "KLC"... Kiln Loving Care! 

Here are a few tips from Arnold Howard at Paragon Industries on how to give your firebrick kiln that extra Kiln Loving Care:

1. Vaccuuming is a must. Vacuum the kiln interior regularly using the soft brush nozzle of a vacuum cleaner. Be sure to vacuum the element grooves, the inner surface of the kiln lid or roof, and the underside of kiln shelves and be gentle when you touch the firebricks with the nozzle. Vacuuming the grooves is essential if you have had anything explode inside the kiln. Pieces of greenware that lodge inside the grooves can burn out an element. Vacuum the kiln often if you use silica sand on the shelves. The sand, which is used to support ware during firing, can ruin the elements if it filters down into an element groove. As you vacuum the kiln, examine the walls for glass or glaze particles that have embedded into the firebricks. Dig these out carefully. Otherwise the particles will embed deeper into the firebrick during the next firing.

2. Kiln Wash is your friend. Apply kiln wash, liquid kiln coating or glass separator to the kiln’s firebrick bottom. But keep kiln wash away from the walls and elements.

3. Dry your greenware. If possible, do not fire moist greenware. It should be bone-dry and warm to the touch. If you must fire moist greenware, wait until all signs of vapor have disappeared before heating past 200 degrees F. The moisture at higher temperatures is not good for the firebricks and can cause the greenware to explode.

4. Be gentle. Lower the kiln lid (or close the kiln door) gently. Slamming the lid can crack the lid the first time it happens. Fully disengage the lid support before lowering the lid. Forcing the lid downward can break the bricks near the lid hinge. From time to time, check the condition of the lid support.

5. Keep closed. Keep the lid closed when you are not using the kiln. This keeps dust out and prevents the lid from dropping while you are away from the kiln. Do not store anything inside the kiln.

6. Level it. The kiln stand should be level and rock-steady. An unleveled stand can stress the firebricks. A stand that rocks can cause the kiln to move when jarred, knocking over ware against the sidewalls inside the kiln.

7. Don't lean on me. Do not lean too heavily against the firebrick walls while loading and unloading. Some people use a small stepladder to reach into a deep kiln. You can also cut a piece of plywood to fit across the wall that helps protect the wall during loading.

8. Try not to touch. During loading and unloading, do not touch the sidewalls of the kiln with anything. Do not allow a shelf to bump into the firebricks. The extra time and care you spend loading and unloading may add years of life to your kiln. 

9. Always look for drips. If glaze, glass, or other materials drip onto a kiln wall or the kiln bottom, repair before the next firing. Otherwise these materials will remelt and embed deeper into the firebricks. Remove the contaminant by scraping gently with a putty knife. If you remove kiln wash from the kiln bottom, apply a fresh coat to the bare spot. 

10. Don't worry! Do not be concerned about small cracks that appear in the firebricks. The cracks are normal and act as expansion joints. During firing, they close tightly.

Finally, if a firebrick edge breaks off, don’t stress. The damage is usually slight and does not affect the firings, and can easily be repaired with our Firebrick Kiln Repair Kit.