Welcome to our Kiln / Furnace Studio. Duralite has been serving glass artists, ceramic artists, teachers and craftspeople for 60 years.


Duralite Inc. manufactures high quality heating elements for electric kilns of all makes and models. We supply  “replacement” heating elements for standard brand kilns, and we also manufacture heating elements for special applications such as custom built kilns and annealers. Duralite heating elements are made to match or exceed the needs of your kiln and Duralite elements are also value priced at factory discount prices.  We also offer a quality line of electrical controls, wiring and hardware products to complete your project with professional results. These products have been field tested and proven successful by artists and crafters like your self.

You can now order many of our stocked products through our secure online shopping site. Complete with product descriptions, order numbers, photos, and prices.
Most items that are in stock will be shipped the next business day.
We are excited about our new web site. The improvements we've made are just the beginning. In the months ahead, we plan to expand the information you see here to make it a great resource for your needs. If you have any special requests, comments or suggestions for us, we'd love to hear from you.

Site Contents:
Replacement Kiln Heating Elements
Custom Heating Elements
Stocked Heating Elements
Temperature Controllers

Thermocouples, Thermocouple wire, and Accessories
Power Controls- Switches, Relays, Solid State Relays
Lead Wire, Wire Connectors and Terminal Blocks
Temperature Control Packages
Quartz Tubing
Mullite Insulators
Disclaimer Statement

Replacement Kiln Heating Elements 
Duralite maintains an extensive database of replacement heating element specifications for most popular kiln brands and models. Duralite heating elements are made to match or exceed the specs of your kiln.

Because you are purchasing at factory discount prices, you will find our prices very competitive.

If this is a first time replacement request, use the form link below. Provide us with as much information as you can about your kiln. We find that many kilns of the same make and model have different heating element designs so it is important that we find out what exactly you have. If you think it will help, you can even send us a sample of the old element.

For repeat orders in the future, just refer to the assigned Duralite “Part Number”.

We will have all the necessary information saved from your first order. Our friendly staff will reply promptly with pricing and delivery information.

 

Custom Kiln Heating Elements 
Building a custom kiln or furnace?  Whether it’s a Front loader, Top loader or Bell/Hat style - for annealing, slumping, fusing, or casting glass - we can help.  Just fill out the “Custom Heating Element Request” form. Duralite's engineering staff will then assist you in the design process, to get your furnace operational. First, we will configure a custom element layout using your design and power requirements. Then we will also recommend any necessary wiring hardware and controls to complete the system package.


Duralite STOCK  Heating Elements
Duralite STOCK HEATING ELEMENTS are purchased directly from our online store. These elements are designed for common voltages and wattages and are well suited to the veteran do-it-yourselfer. Use the guide-lines provided below to help make your selection. Please review the information carefully as we do not accept returned elements that have been fired or modified.  We accept returns on elements within 30 days of purchase if they have not been installed, altered or damaged, and returned shipping paid by customer, for a 20% restocking fee.

Determine the “total wattage” required for your application.

  1. Select the voltage that matches (or is the closest to) your building power supply.  
  2. Select the quantity of elements that will fill your wattage requirements. The number of elements can be multiples or combination of any wattage size of elements. For example, If you need 10,000 watts of heat you can use
    (3) 3,000 watt elements and (1) 1,000 watt element
  3. Determine that the selected elements will physically fit into your application using the element coil diameter and the coil stretch length data listed in the chart. The elements are shipped unstretched and must be stretched to length prior to installation. Each element has a minimum and maximum stretch range. If an element happens to be to long for your application then consider using multiple lower wattage elements which are have shorter stretch lengths.

Stock Heating Elements definitions:

Volts -  Amps - Watts

The element Watts is based on the voltage listed in the table. The element can be operated at different voltages but the actual Wattage will be dependent on your building’s voltage.

Do not operate the elements at voltages that exceed the listed volts by 10%.  You can calculate the actual wattage and amps of the element will be for your supply voltage by using the example shown below.

The actual amperage and wattage is needed to determine your electrical service requirements such as the fuse or circuit breaker size, power contactor size, and the size of the feed wires.

The example below determines the actual element amperage and wattage.

Example:

Heating Element, DURA005677,115 Volt -10 Amp –1150 Watt
Find the actual amps and watts if connected to a 120 volt supply.

  • Step 1:Calculate the element “Resistance” (OHMS), using the table data Voltage and Amps.
    VOLTS ÷ AMPS = OHMS
    115 VOLTS ÷ 10 AMPS = 11.5 OHMS
  • Step 2:
    Find the “actual” element AMPS when connected to 120 volt supply
    VOLTS ÷  OHMS =  AMPS
    120 ÷ 11.5 = 10.43 AMPS (actual)
  • Step 3:
    Then to find the “actual” element Wattage
    VOLTS x  AMPS =  WATTS
    120 X 10.43 = 1251.6 WATTS (actual)

Coil Diameter
This is the element’s “Outside Diameter”.  If you are mounting the element in a groove, you should make sure that the Coil Diameter is less than the groove size. If you are mounting the element over a mullite rod,  the diameter should be larger than the mullite diameter. Remember stretching the coil will reduce the diameter slightly.

Install Length
STOCK Heating elements are shipped “close-wound” meaning that the coils have not been stretched apart, which is required before the element can be used. The element can be stretched to any length within the “Install Length” range as listed. Stretching the element does not effect the electrical ratings, but do not attempt to shorten or cut down the element (except for the tails) to make it shorter.

Element Stretching Procedure
Tools Required:

  • Tape measure
  • Bench vise
  • Locking pliers
  • Safety Glasses

Stretching is a little bit of a trial and error process.  If you have a long bench with a vise you can stretch elements with one person, if not you will need two people. Mark out the element’s installed length by measuring from the end that is held fixed.  Firmly clamp the fixed end in position, and then pull the heating element 10% beyond your desired length.  Note the distance where you stretched to, then allow the element to relax fully. Very likely you will not have stretched it far enough.  Now stretch slightly beyond your first stretch mark. Mark the spot again where you stretched to.  After you have done this several times, you will quickly determine how far you must stretch an element to obtain the proper length.

If you overstretched the element there are a few ways to correct this. If you are only slightly beyond your installed length, loosely shaking the element with the fixed end still clamped will usually reduce the length due to memory effect.  If you are well beyond the installed length and shaking will not reduce the length sufficiently, you will have to compress and re-stretch the element.  If necessary, you may have to run a rod down the interior of the element in order to compress it enough without extreme distortion.

Remember, never cut element shorter to fit it into your kiln.

Cutting coil turns out of an element will cause elements to draw more amperage and run hotter.  In the best case you will shorten its working life; in the worst case you may cause a fire.

Maximum Wire Temperature
This is the maximum operating temperature for the alloy wire of the element. Element life will be affected by the Kiln operating temperature. The higher the kiln operating temperature the shorter element life will be.

STOCK Heating Elements have 12 in. terminal leads of double twisted wire. The terminal leads can be trimmed shorter if required.


Temperature Controllers   
Duralite stocks a variety of off the shelf temperature controllers to meet the needs of most heating applications. Features include single set point ON-OFF temperature ramping and programmable recipe steps.

  • High Temperature Limit Controls
  • Temperature Meters
  • Inputs : Thermocouple Type-K, R, S
  • Outputs: relay contacts , 4-32vdc, 4-20ma 
  • Refer to our listings for details on options and other specific details.
  • Click here to order.   



Thermocouples, Thermocouple wire, and Accessories
Featuring a wide range of sheath materials including stainless, mullite, and alumina of various lengths, diameters and configurations.

  • Temperature sensors, type K, R, S
  • Thermocouple extension wire, type K, R, S
  • Thermocouple connectors, type K, R, S
  • Click here to order.


Power Controls- Switches, Relays, Solid State Relays
Power Controllers feature solid state and electromechanical relays that are designed for heating applications.

Power Controllers are sized by:

  • Supply voltage
  • Power supply configuration (single or three phase) which determines the number of poles
  • Current handling capacity
  • control signal to activate relay
  • Click here to order.

Kiln relays-
direct replacement relays for many of the popular kiln models
Mercury Displacement Relays-
feature high cycle life outlasting mechanical contactors
SSR, Solid State relays-
deliver the finest control, lowest power consumption, and will give the longest element life


Lead Wire, Wire Connectors and Terminal Blocks
The proper element connectors and wiring hardware will maximize your heating element life and performance. Electrical connections are often the weakest link in a heating element system. You should only use electrical connectors that are suitable for the high temperatures and compatible with the metal alloy of the heating elements. Using electrical connectors that are not compatible will cause a corrosion to occur at the connection area. This corrosion increases the electrical resistance at the connection and the higher resistance will hamper the heating element performance.

The electrical lead wire should have insulation that is suitable for the high temperatures and the wire size must be large enough to handle the electrical current or ampere load of the heating element(s). Using undersized wire will cause the lead wire to over heat, and will also hamper the heating element performance.

Click here to order.


Temperature Control Packages

Duralite Temperature control packages are completely assembled, wired, tested and ready to be installed. Power supplies include 120/ 208/ 240/ 480 volt, 60-150 amp single or three phase. Each package is specially designed to fit your specific application and needs. Backed with our support, you will have the confidence that you are getting the best value, quality and performance for your application.

All Temperature Control packages use top quality grade components. Panel fabrication follows the National Electrical Code requirements. The metal enclosure is a rugged industrial quality grade. Wiring knockouts are pre-punched to simplify installation, and mounting feet are provided for wall mounting.

All the controls are pre-programmed to get you up and running as fast and as easy as possible. Complete technical installation, maintenance instructions, and drawings are provided. Factory start up assistance can be provided when needed.

Click here to order.

Contact us for pricing and delivery information.


Quartz Tubing
Quartz tubing is a viable method to install heating elements inside kilns. The quartz tubes provide a relatively easy and stable means to mount the elements and it also has many other benefits. The element is mounted inside the tube thus providing electrical insulation. The quartz is an electrical insulator yet it passes heat with very little absorption. The heating element is protected from contamination which is one of the greatest causes of premature element failure. Heating element flaking and spalling is contained inside the quartz tube thus protecting your work from any debris. Quartz tubes can operate at temperatures to 2,100 F. If a rapid cool down is desired the quartz tube can be used to pass cool air directly thru the kiln walls.

Quartz tube mounting notes
The figure above is a typical example showing a quartz tube mounted inside a kiln. Quartz tubes generally are mounted on the walls or the roof. This example uses heating element wire as hangers for the quartz tube. The wire is formed with a loop on one end for the tube. The remainder of the wire is then twisted together forming a straight portion which is passed thru a small hole drilled thru the kiln wall to the outside of the kiln. Locate wire hangers about 8-10 inches from each end of the quartz tube and then one in the middle of the tube. The hanger wire is then trimmed to length and fixed to the outer kiln wall using sheet metal screws. Sometimes it is easier to install the heating element inside the quartz tube before mounting the quartz tube inside the kiln. Your kiln construction will determine which procedure is best. Orient tubes horizontally for best element operation. Quartz is strong but should not be stressed during mounting and do not use it for any structural purpose.

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Mullite Insulators

This is a traditional material choice in high temperature, high hot strength, and thermally shock resistant products. It is a good thermal and electrical insulator – even at very high temperatures. It has outstanding hot load-bearing properties, and it is resistant to many corrosive environments. It is, in short, the key ingredient in many refractory and ceramic products.

Major Properties:

  • Good high temperature strength
  • Good thermal shock resistance
  • Excellent thermal stability
  • Resistance to most chemical attack; it has excellent stability in acid metal slags and is insoluble in most acids
  • Resistance to oxidation and attack by furnace atmospheres
  • Resistance to abrasion
  • Good electrical resistivity

Typical applications, industrial, commercial and other industries:
Protection tubes, Electrical insulators, Element center tubes, mounting rods and rollers for Heaters, furnaces, and kilns.

Click here to order.

 

Disclaimer: The contents of this document are provided “AS IS”.  This information could contain technical inaccuracies, typographical errors and out-of-date information. This document may be updated or changed without notice at any time. Use of the information is therefore at your own risk. In no event shall Duralite be liable for special, indirect, incidental or consequential damages resulting from or related to the use of this document.

Warning: Some of these discussions deal with electricity and electrical connections.  It cannot be stressed enough – you must always disconnect the power to equipment that you need to service before opening up any electrical boxes or panels.  If you have any questions or are not qualified to work on the equipment – hire a licensed electrician.

 

Duralite, Inc., P.O. Box 188, 15 School Street, Riverton, CT 06065
Phone: 888-432-8797, 860-379-3113, Fax: 860-379-5879


Terms and Conditions, Disclaimer, © Duralite, Inc. 2005