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Orton Witness Cones


Orton Firing Products Logo


   

      In 1896, the first Orton Pyrometric Witness Cone was produced by Dr. Edward Orton Jr's Standard Pyrometric Cone Company to document the proper attainment of temperture in a kiln, thus greatly expanding the application of scientific principles to industrial ceramic manufacturing.  Following Dr. Orton's death, the Orton Ceramic Foundation was started in 1932 as a charitable trust for the benefit of the ceramic arts and industry with an emphasis on scientific study and education.

 

    Today, the Orton SSB Self Supporting Witness Cone is the international standard for temperature documentation in kilns for industrial, academic and the hobby fired arts and other products manufactured by the Orton Ceramic Foundation including Kiln Vents and Digital Kiln Controllers are key components for the safe, accurate and proper operation of kilns in any setting including the classroom and home studio. 

 

    Dogwood Ceramic Supply supplies Orton Witness Cones and Kiln Vents to schools and universities as well as professional and hobby ceramic, pottery and glass artists.  Quantity discounts are available on all products.  Bulk quantities of all products (including Kiln Vents) are stocked by Dogwood Ceramic Supply.






Orton Witness Cones


 Orton Self Supporting Witness Cones


    The Standard Pyrometric Cone Company was founded by Dr. Edward Orton Jr. in 1896 specifically to manufacture a product to verify and document the maximum temperature and proper firing of industrial ceramics. The products were cone shaped and used to witness the firing, hence the name ... Witness Cones or Orton Witness Cones to distinguish the product from competitor's products over a century ago.

 

Orton Self Supporting Witness Cone



    Following the invention of the modern digital kiln controller in the early 1990's, the purpose of the Orton Witness Cone remains exactly the same as it was 1896 ... witnessing the firing of the kiln.  As with advances in kiln technology, the Orton Witness Cone of yesterday have also improved.  No longer is there the need to properly balance and align the Witness Cone on a clay base as the modern Self Supporting Witness Cones allow for easy placement in the kiln thru the addition of a wide self supporting base to the cone.  And unlike years gone by, most people will wait for the kiln to complete its cycle and cool to room temperature before checking the Witness Cones.



Orton Self Supporting Witness Cones


Orton Witness Cones, Before and After Firing


Set of Orton Witness Cones, before and after the firing of a kiln.


     Witness Cones measure and document the heat-work performed in the kiln firing, hence the proper name of pyrometric cones.  Heat-work is a time versus temperature equation based upon the rate per hour of temperature increase to a specific final temperature.  Witness Cone values are based upon the melting temperatures, as defined by heat-work, of common ceramic and industrial materials.  The average temperature difference between Witness Cone values is typically between 20 and 30˚C.

    Witness Cones are commonly used in sets of three adjoining temperatures (Cone values).  As illustrated in the drawing above, 3 Orton Witness Cones of adjoining values, such as 03, 04 and 05, are placed on the kiln shelves a minimum of 6" from the wall bricks. Just prior to the final firing temperature the coolest Cone (05 in the illustration) will over-melt.  At the final firing temperature the middle value Cone (04 in the illustration) will melt into a perfect 90˚ arch such that the tip of the cone has slumped to a point about the same height off the shelf as the top of the self supporting base. The hottest Cone (03 in the illustration) will not bend. Any deviation from the anticipated Witness Cone results will indicate a probable firing problem.  Larger kilns (in terms of depth or layers with multiple elements being used in each layer) will use multiple sets of Witness Cones to verify the firing results throughout the firing chamber.

    Witness Cones should be used in the modern digital controlled kiln to verify the accuracy of the controller and thermocouple calibrations as well as to indicate loading issues or element fatigue problems in the kiln.


    Orton Self Supporting Witness Cones are packaged in boxes of 25 Witness Cones per box.





Dogwood Ceramic Supply stocks the following Self Supporting Cones:


               
SSB 020 SSB 07 SSB 3
SSB 019 SSB 06 SSB 4
SSB 018 SSB 05 SSB 5
SSB 017 SSB 04 SSB 6
SSB 016 SSB 03 SSB 7
SSB 015 SSB 8
SSB 10

 

Stocked by Dogwood Ceramic Supply Logo

 


Pricing:

 

SSB Firing Cone Pricing:

 

Quantity
(Boxes)
Price
(per box)
1 10.00
6 8.00
12 7.00
48 6.00

Boxes of Orton SSB Witness Cones and SRB Firing Cones may be combined for the quantity price.


prices valid until December 2018 





Orton Firing Cones


  Orton SRB Firing Cones

 

     In 1953, the W. P. Dawson Company invented the mechanical kiln shut-off device, commonly called a "Kiln Sitter" or "Dawson Kiln Sitter" to utilize the tip of the Standard Orton Pyrometric Cone in the common electric hobby kiln.  The Orton Ceramic Foundation modified their existing large cones, thus creating the junior or sitter cone, specifically for ease of use with the Kiln Sitter.  With the advent of the modern digital kiln controller in the early 1990's it was readily clear that, like buggy whip manufacturers of the horse drawn carriages 100 years prior, the days of the WP Dawson were numbered and in fact the Dawson company would in fact close in 2008.

 

    Today, the Orton SRB Firing Cone continues to be manufactured and stocked for sale by Dogwood Ceramic Supply to support the kilns we sold in prior years.

 

    The Orton Firing Cone will melt and deform slightly when the proper degree of heat-work (time and temperature) is achieved during the firing cycle, thus allowing vertical movement of the sensing rod which in turn allows the kiln shut-off device to turn off the kiln.  The tapering shape of the cone allows the user to shift the placement in the Kiln Sitter to obtain a slightly hotter or cooler firing depending upon the thickness of the cone under the sensing rod.


   Orton SRB Firing Cones (also known as Junior Cones) are packaged in boxes of 50 Cones per box.  Starting in September 2016 the Firing Cones will be shipped in joined pairs.  Previously the joined pairs were cut during the packaging process at the factory.  This change will reduce manufacturing costs and eliminate the broken tips that resulted from abuse during shipping.




Orton SRB Firing Cones



Junior Cones


Dogwood Ceramic Supply stocks the following SRB Firing Cones:


               
SRB 020 SRB 06 SRB 5
SRB 019 SRB 05 SRB 6
SRB 018 SRB 04 SRB 7
SRB 017 SRB 03 SRB 8
SRB 016 SRB 10
SRB 015
SRB 014            
SRB 013            
SRB 012            


 

Stocked by Dogwood Ceramic Supply Logo




SRB Firing Cone Pricing:



Quantity
(Boxes)
Price
(per box)
1 10.00
6 8.00
12 7.00
48 6.00

Boxes of Orton SSB Witness Cones and SRB Firing Cones may be combined for the quantity price.


 


prices valid until December 2018 











Ordering Information:

    All Orton Pyrometric Cones use an alpha prefix and 1 to 3 digit number to signify the correct item number. SRB is Orton's alpha prefix for the Junior Cones, also known as Firing Cones.  SSB is Orton's alpha prefix for the Witness Cones.  The number values can be confusing. 04 is not the same as 4.  And the "0" in 019 is required as Cone 19 exists for industrial ceramic customers.

 

 

Additional Notes:

 

        The fundamental force driving Firing Cone prices over the past 20+ years has been the sharp decline in demand for the product as digital controlled kilns have consistently outsold the old-style mechanically operated (Kiln-Sitter) kilns.

    Dogwood Ceramic Supply has been in the forefront of the movement to promote digitally controlled kilns.  We stopped stocking kilns equipped with the Kiln-Sitter in July 1996.  We sold our last catalog standard kiln equipped with a Kiln Sitter to a new customer in 1999.  Maybe, just maybe, Dogwood Ceramic Supply might have been the Big Dog driving the market as Paragon didn't make their announcement to cease designing kilns equipped with a Kiln Sitter until 2001.

    Because there are still a few legacy kilns (pre-1999 units) sold by Dogwood Ceramic Supply on the market, Orton Firing Cones will continue to exist in Dogwood Ceramic Supply's inventory of showroom products for the foreseeable future.  However, as the legacy kilns are replaced with a modern kiln, the breath and depth of our Orton Firing Cone inventory will be trimmed to meet real world demand for the product.  Customers needing Firing Cones for unusual Cone values are strongly advised to evaluate their needs in advance.  Dogwood Ceramic Supply places bulk orders with Orton every 60 days and we will accept orders even for a single box of Firing Cones (or for specific Witness Cone values that we do not currently stock).

    Dogwood Ceramic Supply has ceased stocking the Orton BRB Firing Cones in our showroom.  Bulk sales (minimum 100 boxes) will continue to be offered to our commercial customers who choose to provide the product to their customers.   The 100 unit price price of BRB Cones is $7.40 per box.

 

 

 

 





Dogwood Ceramic Supply


12590 Dedeaux Road
Gulfport Mississippi, 39503
Telephone (228) 831-4848        Fax (228) 831-3111



Showroom Business Hours:


Monday, Tuesday, Friday and Saturday 10AM to 5PM
Thursday 1PM to 6PM


Closed Wednesday and Sunday



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