I personally got tired of pit firing. It is beautifully random and also rewarding for the work involved. Yet the limitations of colorants kinda got me bored. Burnishing isnt absolutely necessary. Ive enjoyed pots colored by the flames and then coated in acrylic spray brings out deeper tones like the pot was wet. Youll see the colors more vibrantly when cleaning with water but once dry some of the lighter flashings wont be visibly, thats where the acrylic comes in. I have had very little breakage doing pit fires and thats with making the whole stack, tossing gasoline, and fire away. Yet I have used a white stone ware primarily by Highwater. Most were slip cast by this stone ware, not true slip, just made a slurry and defloced then poured. Micaceous red clay is very lovely. I have used natural GA clay which is loaded with mica. Mica though looses its luster in higher fire, but for pit fire you stay low fire to keep the clay porous to accept better coloring.
I live in NE Georgia and have gotten good results during winter. Zone 8/9. I had a small dug pit and I would bury the pots on top of at least 6 inches of saw dust/salt/copper carb. Then continue with the saw dust covering then layer after layer make the materials bigger and bigger till it was about 2 - 3 feet about the hole. I would continue to add wood (lightly) as it burned down till ground level, mind you the hole was about 2-3 feet down so the fire was still good and strong. I considered the amount of coal that results from a typical fire and continued to add wood to make it good and hot but also to leave a nicely large coal bed in the end that almost covered the pots. Once I figured it was just about done and low enough I covered with a piece of tin.
That was one of my first ones. ALways make sure there is enough air flow but not too much. You want a nice HOT but slow burning finish. The wind blew in the direction of where the rock was missing and it was just enough to keep things going. One thing I will say is give it a day or two before digging it all up. You will be amazed at just how long ashes will stay hot enough to burn you. Not to mention the pots retaining the heat. I ruined a pot once by pulling them up too early and melted a big black rubber thumb mark from one of my gloves. One of my best, which isnt the best out there, but I was very pleased was this guy. Just Salt/Copper carb/ saw dust/ wood/ and a small amount of cow manure.
One thing to keep in mind is that some potters accomplish great pit fire flashings by pitfiring then refiring in a kiln to burn off some of the colors then pit fire again. Ive never tried it. Believe it or not that one has been glossed with acrylic and has held a plant for the past 5 or so years in a sunny room and never lost its colorings. Some say the reds will fade in the sun. I left a pot on a pole, uncoated in the sun for over a year and no signs of color loss. Roll with the punches and give pit firing a try. Im glad I did but other avenues opened up for me. I still consider it from time to time because where I live I can access tons of free wood etc to accomplish everything.
Not to derail the thread but how would one achieve a slower cooling process with only a nob controlled kiln. I have low - med - and high. Ive been wondering that if upon shut off how fast "high" raises temp, if "medium" keeps things consistent, and whether "low" keeps things gradual. I havent put much thought into it glaze wise because Ive only thought about it during glass melts. But Im sure like some of us I never knew that fact that J Baymore stated. I guess it makes sense considering those ridiculous crystal forming glazes take long cooling times.
I was going to say the addition of ash might help. SOmeone already said it! Darn. Maybe a heavier coat on or near the rim, the addition of ash or something that will make the glaze flow more, or in conjunction add some texture where the flow can be interrupted and pool. Ive been following Katie Marks "anotherseattleartist" in instagram. Her direction is something Ive aimed to do. Not sure what glaze she uses but its simple and drools downward and pools nicely. Plus she uses gold luster which Ive been wanting to use silver luster for some time now.