John Baymore's

KILN GALLERY

Here are a few examples of various types of kilns John has built.......

ITC Lined Soda Kiln with Hinged Door

This soda kiln was constructed during a week long workshop. It was constructed mainly out of Thermal Ceramics insulating firebrick which is known for its resistance to soda vapor. The hot face was then spray coated with ITC 100HT in order to further help the lining to resist the destructive action of the soda. The kiln features true downdraft design with tapered flues located in the floor, numerous round soda ports lined with cast hard refractory tubes, a hinged door, and a dual zone pyrometer system.

67 Cubic Foot Car Kiln

John's Design Drawing                                Actual Kiln on Site

This crossdraft car kiln has features such as a UL / NFPA rated industrial grade refractory chimney, and a car that rolls directly into the artist's studio for loading and unloading. Constructed primarily out of many different grades of insulating refractories, the firebox cold face around the burner ports has an exterior lamination of coated ceramic fiber board to improve the insulation value.

Car heat seal from the 67 Cubic Foot Crossdraft

50 Cubic Foot Downdraft

John designed this true downdraft sprung arch kiln for a community art center. It utilizes a pair of dual nozzle forced air burners with continuous venturi pilots firing on propane. The key lock activated flame safety system, requiring a "two person present" ignition sequence, is at a mid-range level of technology, and utilizes pilot switches, function indicator lights, solenoid actuated gas valves, and monitors positive draft flow. "Flame out" activates an alarm when it shuts down the system.

Three Chamber Noborigama

This three chamber climbing kiln was built on an artificial slope created in the kiln room at Massachusetts College of Art right in downtown Boston between Children's Hospital and Beth Israel Hospital. It featured a dual pair of chimneys which housed a small afterburner system to eliminate most visible smoke. Smoke leaking off of the stoke holes and the blow holes was handled by the general room dilution ventilation.

Downdraft Kiln

This type of basic sprung arch downdraft kiln design is probably the workhorse of handcraft potters here in the USA. This particular kiln was a "rebuild" John did of a poorly proportioned unit to improve its performance. Re-using most of the original refractories, it was changed from the very common (but poor) "hole in the back wall" exit circulation into a true downdraft with exit flues in the floor below the bottom shelf, the height to width ratio was changed, the arch shape and buttressing was improved, and the burners upgraded.

These changes greatly improved performance, and quickly paid for themselves through decreased seconds and wasters.

Small Two Chamber Noborigama

This small low wood kiln is a hybrid between an anagama and a noborigama, and utilizes sprung arches. Construction utilizes hardbrick, red building brick, local dirt, and a rammed fireclay and vermiculite insulation. While it has two chambers, the crossdraft proportions are low and wide...imparting great horizontal movement to the flames. There are no separations between fireboxes and ware stacking and it produces excellent flashing and ash deposits. It typically is fired from 24 to 48 hours.

Large Sprung Arch Downdraft

This 90 cubic foot propane fired kiln had four forced air burners developing a total heat input of approximately 1 million BTU's. This kiln was the prime unit used for processing huge volumes of elective student work in a major college ceramics program, as well as for firing large scale sculpture. It is shown here loaded with a grouping of loaded saggars for a high temperature firing. This kiln typically fired within 1/2 a cone difference top to bottom.

Two Chamber Noborigama

John consulted on the construction of this small two chamber noborigama with a young potter just getting started in his clay career in wood fired porcelain.  It was constructed out of a combination of an insulating firebrick backup over a hard firebrick lining. It has an attached external firebox (dogi) that was composed of one half of a catenary arch, and dual chimneys with independent dampers.  It is fired with scrap pine lumber slab and edgings from a local mill.

Small Catenary Arch Downdraft

John rarely utilizes a catenary arch to form the entire kiln structure, however this is one of the times he did. The kiln features a layer of protective sheet metal bent into a curve just over the layer of ceramic fiber that backs up the 4 1/2 inches of arch brick. Catenary arches are beautiful forms, but the space that they contain can be difficult to utilize effectively. Note the numbering on the brick for the door.

27 Cubic Foot Crossdraft

This small kiln was designed to be suitable for the avocational or hobby potter who wants reduction firing capabilities. Crossdraft circulation provides more stackable space than a comparable sized downdraft, and the sprung catenary arch minimizes steelwork.

Resort town zoning issues greatly impacted this design, and the aesthetics of the general site were important. Great attention to detail gives the unit a "clean" look. The lightweight metal roof structure and minimal foundation were designed to support and protect the kiln yet still fit within the town's definition of "temporary".

Two Chamber Gas Fired Kiln

This 80 total cubic foot kiln, shown undergoing a repair session, was designed by John to fire stoneware in the first chamber and salt glaze in the second. A unique feature is the two fixed burners sidefiring into the second chamber which have gas-tight swivel joints between the gas/air mixing unit and he flame retention nozzle, allowing them to be moved out of the way in order to seal the burner ports at the end of the firing.

Small Temporary Anagama

During a week long raku workshop held on the beach, John found himself with a large excess supply of hardbrick. A convenient sloping bank nearby, some collected driftwood and construction offcastings, and soon a small temporary tube type kiln emerged. The only insulation was the dirt that the hardbrick were embedded into during construction. With both the raku kiln and the wood kiln going, everyone got their share of smoke and fire! After the workshop was over..... this kiln was dismantled and the brick was re-used.

Updraft Burn Out Kiln

This large updraft car kiln utilizes four self-contained burner/flame safety units. It is designed for the burning out process that precedes the pouring of bronze into large scale investment casting molds. An overhead crane is utilized to place prepared molds onto the car. The molds are removed from the kiln on the car while they are quite warm, and the bronze is poured. Because of the rough working environment, the burner system is protected by heavy steel "bumpers".

Two Chamber Gas Kiln

This is the door arch being constructed on the first chamber of a 120 total cubic foot two chamber gas kiln. The first chamber was 80 cubic feet and the second chamber was 40 cubic feet. It was fired on propane utilizing three Ransome venturi burners with continuous pilots. The second chamber was used solely for bisque, firing completely on waste heat from the first chamber.

Note the heat reclaiming system embedded in the subfloor refractories. This liquid system was used to extract heat from the cooling kiln for studio space heating. It stored heat in a large insulated water tank.

Updraft Car Raku Kiln

This raku kiln features the ease-of-use of a car to make access to larger wares a snap. Because of the small size, lightweight steel could be used throughout. This kiln was fired on a single forced air burner utilizing low pressure natural gas. Flame safety was by Fireeye UV detection. A single flip of a switch at the kiln would shift it from pilot mode to the last setting the main burner was at... for ease of ware removal and reheating.

The burner was sized and the refractories were selected so that this kiln could also be used as a high temperature test kiln.

40 Cubic Foot Crossdraft

This crossdraft kiln with a brick in door, utilizes a backup insulation made of vermiculite and fireclay rammed over the four and a half inch thick insulating firebrick arch. The arch type is a "sprung catenary"..... a wide catenary curve set up on vertical walls that requires minimum buttressing. It is fired with four Maxon high pressure venturi burners.

Low Tech Burner Installation

John's burner installations pictured to the right and left are pretty typical of those found on a great deal of handcraft potters kiln installations, particularly those in more suburban areas. These particular units are Ransome venturi burners with continuous Ransome pilots, and the flame verification is being supplied by simple Penn-Baso thermocouple actuated safety valves. This simple approach to both combustion and flame safety is a very common solution where medium and high pressure propane is available.

Medium Tech Burner Installation

The flame safety system pictured here fills the gap between complicated and expensive electronic systems and the simple electro-mechanical "BASO" valve systems. It utilizes simple solenoid activated valves along with a 24VAC control circuit with various simple sensors to provide many of the functions of more elaborate systems. It is key switch activated, requires two people present to perform pilot ignition, monitors all pilots for flame proof, monitors electrical power to the combustion air blowers, monitors positive draft on the ventilation system, sounds an alarm upon loss of any function, and has a remote emergency shutoff switch at the kiln room door.

High Tech Burner Installation

Sometimes John becomes involved in a project where regulations and codes become very restrictive, and far more complex combustion systems become necessary. The control panel at the left is the "brains" behind a fifteen burner natural gas installation in an major city setting. The automatic controls include such things as hydromotor gas valves, spark ignition, UV flame detection, and system sensors that measure gas and air pressures, draft flow, and the like. On the right is the typical plumbing of the North American Combustion forced air burners with interrupted pilots for this system, shown on a single kiln unit.

Combustion Design Drawings

In many cases, John needs to develop engineering type drawings of the proposed system, both so that the gas plumber can actually install the plumbing work correctly, and also for review by the authorities having jurisdiction over the installation.

Experimental Venturi Flue System

This slot-type exit flue system was designed in 1979. It features a smoothly tapering opening coming out of the interior of a crossdraft kiln chamber. The narrow "slot" exit flue, of approximately 2 inches in height, runs across almost the full width of the lower chamber wall. It is greatly restricted in square area when compared to the "rule of thumb" concerning the relationship of inlet flue to exit flue sizing. This small slot opening then transitions smoothly into the draft stream leading to the chimney. The complex flaring exit area after the narrowest restriction maintains a slightly increasing cross sectional area as you move away from the kiln chamber.

This concept was implemented in order to alleviate the high "K factor" resistance introduced into venturi operation by abrupt refractory transitions.

© 2000 J. Baymore all rights reserved

Studio visits welcome. Please call 603-654-2752 to make sure I am there.

This page last updated:

08/08/2003 03:56 PM