A kiln is a versatile piece of equipment in a studio whether you want it for ceramics, glass or metal clay. However, the prices can range for more than $300 for a small table top variety to thousands of dollars for large capacity kilns. In most cases, you'll be limited to electric as the heating option. Because it heats cleanly and efficiently, propane can be a cost-effective option for a kin.
Choosing a Location
Since most propane kilns are fixed in place, choose a permanent location. For example, choose a location that is well ventilated to avoid accumulation of fumes and smoke.
Choose an area that will tolerate high temperatures well with adequate clearance on all sides. You should be able to walk comfortable around all sides and access the door or lid easily. Although the outside of the kiln stays fairly cool, the kiln should be away from all flammable objects.
Check on local building codes and permits before you start building.
Assembling the Oven
If you can weld, assemble an angle iron frame for the size kiln that you want. You can also check with your local community college or trade school for a list of welders willing to do small projects. Once you have your frame, position it in the area that you'll be building your kiln.
Lay the layer of concrete block for the base of the kiln.
Cover the concrete block base with the patio stones.
Soak the bricks with water as you work so they don't dry the mortar too quickly. Drill a 1/2-inch hole in one brick to insert the thermocouple. Drill openings or cut the end of of 2 bricks for the propane burners. The bricks for the burners should be placed near the bottom of the kiln at opposite ends. Consider ease of access when placing the bricks.
Lay the bricks on the base applying a thin coat of mortar as you work. Cut the bricks to fit.
Build up the walls with the firebricks and mortar. The corners should fit against the frame.
Place the sheet metal arch on top of the walls with the edge extending slightly so that you can take it out after the bricks are laid. Cut 1/3 off the end of one brick for ventilation.
Start laying the firebricks at the edge and work toward the middle. When you are finished, carefully work the sheet metal arch out from under the bricks. The weight of the bricks wll hold the roof steady.
Attach the hings for the door to the kiln. Assemble the door with firebricks and then attach it to the kiln.
Connecting the Propane
If you have propane in your home, you can tap into that with the aid of the professional at your propane supply company or you can use a separate portable tank.
Fit the burners into the pre-cut openings so that they are secure.
Follow manufacturer's directions to attach the burner's to the copper pipe and shut off the valve.
Use the T-valve to direct the propane to the separate burners.
Insert the thermocouple into the small drilled hole and enjoy your new kiln.
It will take several firings to adjust the timing and temperature of your kiln. Keep a careful log of the information and use firing cones.
When working with propane, observe all safety warnings. Consider having a professional install the heating system or have it inspected after you install it. Periodically, check your propane system for leaks.