How to Make a Simple but Effective Kiln
Fire kilns are easy to make but require a lot of attentiveness to ensure that a regular temperature is maintained. Essentially, you will create a small fire and allow it to crumble to burning embers in a pit. Place the items that you wish to heat-cure around the edge of this hot center in order to slowly warm them up. This will minimize cracking or warping during the heating process later on.
Take some soft wood, such as ash or pine and chop them into little strips that are about a foot long and couple of inches thick and wide. Cut some smaller strips of wood that will act as a support to keep the items that you are cooking above the bottom of the fire. This will help to maximize air flow while regulating temperatures around the objects. Place the items on top of the supports and then take four of the bigger strips and make a square border around the objects.
Take some of the hot embers and place them on and around these pieces of wood. Create a few more successive layers while angling them so each new square is rotated a little bit. Keep repeating this until you have constructed a wood frame that is a couple of inches taller than the items that you are cooking. Then, lay some similar strips of wood at a 45 degree angle to the top of the square frame. Then add some smaller strips at a 90 degree angle to those.
Take some longer and thinner strips of wood and start to build a tepee around the structure that you’ve just created. You don’t want the wood to be too thin, but it needs to be thin enough to catch fire without quickly burning and collapsing. It’s okay if the tepee collapses over time, but you don’t want the whole thing to crumble in just a couple of minutes, otherwise the fire won’t generate enough heat to serve its purpose.
Keep feeding the fire by adding more wood between the tepee and the top layer on the square. Repeat this process in order to maintain that steady, hot glow that emits from around the center of the kiln. A good kiln-fire should burn for at least four or five hours, so continual vigilance as well as access to a steady supply of wood is important. After the allotted time has passed, you can allow the fire to cool naturally until you can remove the logs and uncover the material that you have been cooking. Allow to cool in the ambient air before handling.
Keep in mind that it’s important to keep the pottery or items that you are curing away from direct flame for as long as possible. This is why you should let the embers heat the center before assembling the fire. You want to achieve a nice red glow in order to maximize the quality of the kiln, and this requires a bit of patience and nurturing. However, the center of the kiln will be self-feeding once the framework has been constructed and is continually maintained.
While this is not the most permanent or hands-off kiln to make, it is one that can be constructed with minimal material and time. Try it out for yourself and tweak as necessary. Knowing how to perfect this hack beforehand will make things a lot easier when the time comes to put it into practice.