24 November 2019

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


COLDWORKING

KILNFORMING

Want to see the full list? Check it out here...  Index of Frequently Asked Questions!

09 November 2019

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! 

26 October 2019

Ask Arnold!

Arnold Howard, a former employee at Paragon Industries, is now an independent kiln technician at Howard Kiln Services. For those who don't know him... Arnold started at Paragon in 1977 and worked there for 42 years! Repairing kilns and helping people is Arnold's passion! He is a wealth of knowledge and we welcome his insight!

To start things off, we thought we would ask him a few of our most common customer questions...

Q. Why would someone choose mercury relays over solid state relays? Is there an advantage to one over the other? 
A. Mercury relays are extremely reliable. They rarely fail even in glass schools that fire kilns every day on long annealing cycles. Solid-state relays are just as reliable. But they produce heat, which must be dissipated, or they will fail. To prevent overheating, solid-state relays are mounted in the control panel of the kiln as far away as possible from the firing chamber. Or they are mounted on aluminum plates that pull the heat away from the relays. The kiln industry is moving toward solid-state relays because of state environmental regulations.

Q. Can I make a converter plug so my 240V-30 amp kiln can plug into a 240V-50 amp receptacle? Is that dangerous? 
A. It isn’t dangerous. The Paragon TnF-82 is a 30 amp kiln, yet it has a 50 amp plug for a 50 amp wall receptacle. The 50 amp circuit breaker will still protect the 30 amp kiln from an electrical short. The disadvantage to a converter plug is that it adds an extra connection (the converter plug) to the circuit. If you make a converter plug, check the temperature of the cord from time to time during operation. 

Q. My kiln temps keep bouncing 10F degrees up and 10F degrees down from the set temperature. I work on delicate things and proper temps are crucial, why can't the kiln be more exact? 
A. The thermocouple type has a lot to do with temperature fluctuation during holds. The thermocouple reads the temperature inside the kiln. A heavy thermocouple with thick wires responds more slowly to temperature changes than a thermocouple with thinner wires. The slow response time of the thermocouple adds fluctuation to temperature holds. A sheathed thermocouple, which is the type that has a metal covering, adds more fluctuation than a thermocouple with a bare welded tip. To reduce temperature fluctuation, slow down the firing rate before the kiln reaches the hold temperature. Some controllers do this automatically.

Q. I think my kiln has a hot spot/cold spot! Why does this happen, and how can I fix it?
A. An open peephole can cause a cold spot in your kiln. For instance, if the kiln is equipped with a downdraft vent and the peephole plugs are left out, the bottom of the kiln will become cooler. A lid that rises in the front can cause a cold spot at the top of the kiln. A front-opening kiln that doesn’t have elements in the door will be cooler at the front than at the walls. The easiest way to improve heat distribution is to slow down the firing rate. You can improve heat distribution by adding more thermal mass to a hot spot and removing thermal mass from a cold spot. In a pottery kiln, add more ware to the hot area and less ware to the cool area. If the edges of a shelf in a glass kiln are getting too hot, place 2” wide strips of cordierite shelves along the hot outer edges.

Q. What's the life span of my thermocouple? How often should someone change it to keep the temps consistent? 
A. The hotter the firings, the shorter the life of the thermocouple. Thermocouples in glass kilns last much longer than the ones in pottery kilns because glass is fired to lower temperatures than pottery. Recently I saw a 15-year-old glass kiln that still had the original thermocouple. Heavy, 8-gauge thermocouples last longer than 14-gauge thermocouples because the 8-gauge wire is much thicker than 14-gauge. To know how long your thermocouple lasts, look at the welded tip. A flaky tip indicates a lot of wear. Keep a kiln maintenance logbook and record the number of firings between parts changes.

Now it's your turn... Have a kiln question? No problem! All you need to do is Ask Arnold!

22 September 2019

Introducing the NEW Olympic 1313FLE!

Introducing the NEW Olympic 1313FLE! Isn’t she pretty? This oven is part of the Olympic Heat Treating Series and is ready to ship within 3️ business days!

When you've got metal parts to heat treat, Olympic has the kilns you can count on! No matter the size, shape or temperature necessary, Olympic makes the perfect heat treating kiln for your workshop, lab, or manufacturing floor.

Available in multiple configurations, the Olympic heat treating kilns can handle any type of metal and just about every annealing, normalizing, or hardening process necessary. They are available with swing doors or guillotine doors that are constructed with heavy-duty hardware for years of hardworking personal or commercial use.

Every model in Olympic Kilns' Heat Treating Series delivers:
  • Dependable heat from strong, long-lasting, heavy-duty elements.
  • Reliable temperature control from a variety of true-tested digital controllers.
  • Capable interior space in multiple configurations with attached stands. 
  • Strong construction that lasts and lasts through years of use.
  • Superior and cost-efficient insulation due to the finest high-fire 3" brick.
  • Trouble-free maintenance with Electrical Parts Kits.
  • Solid State Relay upgrades are available.
  • And, of course... fast and friendly customer service assistance when you need help, you can count on them!
Add one of these to your shop, and you're set for any job that requires you to be a metal master!

07 September 2019

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.