Pyranha-Gama June 2024

This firing was a huge step forward in many respects. Although this kiln has produced amazing pots all along...over the past few years, I've progressed towards loading about twice the work into the kiln since 2011 when it was built. Back then, somewhere in the range of 6-8 banquet tables of work was fired in the kiln. Granted, larger works filled the majority of the kiln space, but there was a ton of open air space in the kiln in the early years. Since the onset of Covid and the construction of the Guppie-Gama....I've been progressing with loading/firing technique. A major discovery with the Guppie was that a tight, super tight stack, at the tail provided the necessary thermal mass to retain heat at the back. At Jack Troy's suggestion, I finally acquiesced  and added a sutema. This was a nice solution as the availability of an abundance of smalls was not always present as I relied on guest potter work for that section. The steadfast presence of the sutema relieved the varying availability of smaller works that could be packed tightly...holding heat and slowing the flame. I realized later that a combination of maintaining a deep ember bed and using specific species of wood helps.....namely White Pine for ember bed management and hardwoods such as Red Oak, Black Locust and Black Cherry. Maple, Tulip, Black Walnut...not so good.

This particular firing was special in that we achieved cone 11 at the tail. A few keys to the success of this firing involved a combination of decisions made. Firstly, we had an abundance of White Pine on hand and used it throughout the last two days of firing to manage the ember bed. We kept the ember bed low in the main firebox for the last 24 hours plus...this resulted in smooth natural ash melt on the firebox pots. A technique that is different than recent firings in that the pots were buried in a bed of embers and show the unmelted ash effects in contrast to the rivers of natural ash on the bottom sides of the pots. I've grown to love this aesthetic range and will return to it in the future....just trying to familiarize myself with the array of effects offered by the kiln. I took a peek in the kiln yesterday morning as the kiln was down to 1400F after about 15 hours of cooling. I did one hour of reduction cooling and saw that the FB pots were glistening with contrasting sheets of ash glaze. Cannot wait to unload. A rule of thumb is that if the FB pots look nice...the rest of the kiln will be good....^11 down on the side  and 12 flat in the front. 

We reinstituted a side stoke firebox this time and found that stuffing it with wood every stoke was key. The kiln was stacked to push the flame into the sidestoke area...see photos. The front top was loose to encourage firebox combustion and right behind the front top, in the second row, the top was stacked tight to encourage the flame to drop into the side stoke...it was powerful and effective. The sidestoke firebox was on one side of the kiln and open from the floor to the ceiling with a stack of shelves at the back/far side of the kiln. One shelf was placed at the top center so as to continuously fill the ceiling with pots front to back. A benefit to the side firebox was that there was a channel to access the top center of the kiln....a challenging spot when the FB is omitted. 

We fired with mostly green thick split hardwood and blended in up to 50 percent Pine as we reached and maintained top temperature. The kiln was set at full draw for the last day plus with little air entering in from the front. A 3x3" opening in the front center above grate with a .5x3" opening on either side. The primary air shelves were set nearly closed at the center and leaned against the kiln face at 10 degrees. 

Next time around, I think we'll pull back on front stoking a little earlier in hopes of lowering the temps a bit....12 melted flat. We'll then concentrate on firing off the tail and holding for more than a day. We unload in a few days and I'll post images on IG and hope to remember to add a few pot shots here. This blog serves to help me remember firing details....totally reach out if you actually read this or have any questions. It's so exciting to make strides and discoveries...thanks to all of the amazing people who have chosen to be a part of our progress ;) Trev

An excerpt of my thoughts from email correspondence with Jack Troy that covers post unloading analysis of the firing:

"There were two firings this Spring. The Guppie produced some outstanding works. I'm most excited about the experience we had in firing the Pyranha-Gama as that kiln has proven itself to be challenging...we finally cracked the code to some degree. A combination of a fully mudded chimney - base to chimney top,   a new stacking method and ample White Pine made all the difference with ember management...plus, a side stoke firebox chamber. We fired a bit on the hot side in front, 12 flat and 11 down with 12 moving in the back half. Color was burned off of a bunch of the porcelain up front...very muted tones. I also down fired briefly for an hour as the front of the kiln transitioned from dull red heat to black. There was bright orange flashing on some of the porcelain in the center of the kiln along with some deep purlple-y Redart slips. The firebox pots were  clean as we kept the ember bed low during the last shift. Next time, we'll lay off the front for the most part and concentrate our efforts on the side stoke for the last half day or so. 

Many losses were involved as the high temps challenged the constitution of the shells and tumble stacking proved itself to be a whole nother set of considerations and solutions to be found. Trivets and Crowns..here we come ;) Flat scallop shells should solve a few issues as well. We used a lot of clams which aren't the best for tumble stacking as shrinkage and the sharp curves of clam shells have a compounding effect on the movement of work as it matures.  Quite a relief to have made a huge step forward with the biggest kiln. Years ago we fired the same kiln with about half the work (6-8 banquet tables of work) and most recently, 12 plus tables of work filled the kiln. The massing of the stack seems to have been right in that the top-front was tumble stacked with larger works and a birdbath (as shown in the image of works pre-set and measured on the ground). This seems to have made the firebox happy with extra space for combustion (I've been stacking tight to the top front i the recent past). After that...tight to the top in the second row and a bit looser on the bottom half. The flame was provided a path that led to the side stoke which affected the heat distribution and atmosphere without any finickey challenges. We found that simply stuffing the firebox anywhere around the same time we front-stoked worked well.  Thick-split hardwood was used to dampen heat gain in the front...although we definitely went a bit "too" far by conventional standards. I will say that crystal formation in the shinos and in the Redart slip over fireclay benefited and that temp range offers a unique  beauty that we'll revisit in the future...
I look forward to seeing you in a couple weeks if that fits into your schedule. I also have a trip out in your area of the world planned for later in August...hoping to pay John Peachey a visit when a few pieces are complete. I'll keep you posted. Thanks again for connecting us! Wondering if a late morning visit to you may work into the plan? I'm planning to stay over with Jen Adamson, (I appreciate your offer to have me overnight) hoping to see you  and head back home the same day....I'm feeling the time crunch a bit while committed to making time to do fun stuff like plane spotting, hiking and generally enjoying the summer with family."
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