APM heating elements are made from powdered metal. They last longer than standard element wire and are recommended for cone 6 and hotter firings.
APM elements install the same way as standard element wire, except for the element connectors. To install the connectors properly, insert the twisted wire end through the hole in the connector. Then rotate the connector until the screw presses against two twisted strands of wire. If the screw presses against only one strand of wire, the connector can become loose. Because APM wire is harder than standard element wire, the element screws need more metal to bite into.
Several weeks ago I sent out a kiln pointer on repairing an element that fails at the connector. Tony Rodriguez, a kiln technician in San Antonio, Texas, sent me a pointer on that topic that I want to share with you.
Here is the original kiln pointer:
Ordinarily the only way to repair a burned-out element is to replace it. The exception: When an element burns out at the connector, you may be able to install a new connector and salvage the element.
Elements rarely burn out at the connector. This type of failure is due to a loose connection, which builds up enough heat in the connector to break the element wire. This is why it is important to securely tighten element connectors when replacing an element.
The following instructions are for Paragon kilns, which use barrel connectors. If your kiln uses a different type of connector, the basic principle still applies.
You have a burned-out element. To replace the element or connector, disconnect the kiln and remove the switch box (control panel) from the kiln. You will see two element connectors for each element in your kiln.
If the element has burned at the connector, you will usually see a bare, twisted section of element with a missing connector. This is because the element connector falls off the broken element end.
Does the burned element end have enough length so that you can install another element connector? (With Paragon’s barrel connector, you will need about 1/2” of element length to install another connector.) If not, gently pull the element end with needle-nose pliers. There is sometimes play in the element. If so, you will feel the play as you pull the element end toward you.
If you have 1/2” of exposed length at the element end, you can install a new element connector and salvage the element. Please do not remove the porcelain insulator located under the element. (Not all kilns have porcelain insulators, by the way.) Removing the insulator will give you extra element length, but the insulator is there to prevent the element from shorting out against the kiln case.
Check the element lead wire for heat damage by bending the wire. If the insulation is brittle, replace the wire.
Here is Tony’s suggestion:
"To gain extra element length to install another connector, use a propane torch. Disconnect the power. Then heat to red the element inside the kiln where the element goes out through the firebrick hole.
"GENTLY and SLOWLY pull the pigtail to get the extra 1/2" needed to install another connector. You will usually need even less than an additional 1/2", because some of the wire inside the connector will still be good.
"You must use sandpaper or grit cloth and clean the end of the pigtail before installing the new connector. If the old connector has to be reused, then use a round file to thoroughly clean the inside of the connector hole where the pigtail is to be tightened by the steel screw." Tony Rodriguez email@example.com
Thank you, Tony, for another excellent idea.
With best wishes for July,
Arnold Howard Paragon Industries, L.P. - Better Designed Kilns 2011 South Town East Blvd. Mesquite, TX 75149-1122 Voice: 972-288-7557 & 800-876-4328 / Fax: 972-222-0646 firstname.lastname@example.org / www.paragonweb.com