This was a firing to remember! Along with a stack collapse as we finished loading, there was a halted firing and restart. So many challenges this time around. My mindset is to find solutions to problems. Luckily, by and large, the crew was understanding, trusting, patient and supportive as we fixed the problems. 

Regarding the shelf collapse...luckily, the work was all mine and my friend, Mike Perham's. Mike is on the local crew and I knew he's understand and deal with the setback and loss of work! Thanks Mike!
The issue arose from a fired wad atop one or more posts. Lesson learned, all posts will be tuned up on the wet saw for each firing into the future.

The firing halt/restart was another...possibly related story.  The top two sections of the second stack in from the firebox leaned forward. Luckily, this was visible via the side firebox stoke port. After finding that the lean was gradually progressing...there was no choice but to stop stoking! An experience entirely foreign to me and one not to be repeated anytime soon.

After conferring with Pascal Chmelar and Jack Troy, we moved forward with a crash cool. Years back, when firing my first anagama for the first time, I overlooked closing down the active dampers. The pieces were unscathed by the fast-cool...although the colors were oxidized; residing in the grey/yellow range. This recollection gave me confidence to crash cool the Pyranha. Knowing a sutema offered further thermal shock protection, that part of the solution was set. 

Finding that the kiln was 500F the next morning gave me reason to expect that an unstack/reload was a possibility for that afternoon. Joseph Lyon, Pamela Woodworth, Rachel Dove and Matt Johnson met with me that day, executed the preparations and we successfull restarted the firing that evening.

Moving on to the firing proper, the rest of the burn was relatively smooth cruising.  Knowing that the kiln was filled with vitrified work, we had reached cone 10 up front, the gradual heat progression was key. I topped the kiln with a kiln shelf. I noticed, in the previous firing, that a blocked chimmney serves to drive heat accumulation to the tail while shortening the "campfire" flame...thus protecting the firebox pots. Mistakes and information provided the solution. So cool.

As we progressed in temperature, we arrived at body reduction under full draw in the back and generous incoming air in the front.  A half hour of moderate reduction with active dampers closed did the trick. After BR, we tuned the kiln to "hover" with all passives open both top and bottom. Front primary, secondary and stoke port were positioned to open. We arrived at the front being entirely open in response to monitoring the exit flame. The initial long flame died out at about eye level. Once mature, the firebox flame died out just as it exited the sutema as witnessed through the floor level passive damper openings. 

In retrospect, the flame was riding high on the kiln ceiling for longer than necessary. 18 hours or so of soft flame, that rode the ceiling, was proving to fall short of feeding the side firebox. Once the lower passives were blocked, the flame fanned out from the ceiling and fed the side firebox. We had been using pine in the side in order to close the heat differential from front to back. Eventually, we switched over to hardwood stokes in the side. The kiln ate it up. The hover-stoke method showed itself to be forgiving in that stokes up front rebounded in temp with consistency throughout the firing. The front cones moved gradually while allowing the back to catch up. This is the first firing that we've avoided knocking 13 down. Cone 11 on the side was on the move and finished at 1/2 way down at 9o'clock. The tail was at ^10 and above for 18 hours. The front had top cones on the move...very slowly...for the better part of two days.

In lookin back, a lot of ash missed the pots while the flame was lazily drifting from the firebox...this was early on as mentioned. We can adjust next time for sure. I'd also like to bring the back up more in tandem, temp-wise, next time around. 

One of the interesting things about the hover is that the fired effects range from heavy reduction at the core to strong oxidation at the front and tail. Seeing the same clay bodies and glazes respond in their own ways in relation to the atmospheric conditions provides a wider color pallet and lots of information to process for next time. Although we've employed the hover in the smaller kilns over the last 9 months, since Feb. 2025, there was question as to whether the larger Pyranha could hover-rise....I'd only hovered the kiln for the fun of it in the past. It was only last Feb. that I found a use for the hover beyond playing around.

Paying close attention to the burn cycle was another benefit...especially as the stoke door remained open throughout each stoke cycle. The initial spiraling smoke which was followed by intense flame, then dank off-gassing to clearing was a cycle that repeated itself. I found myself monitoring the stoke timing through visually witnessing the atmospheric conditions rather than keeping an eye on the ember bet. I've grown accustomed to assessing the condition of the cordwood first and atmosphere second. It's always thrilling to take clear and present steps in a new direction...whether at the wheel, among the stoke crew or running the kiln....mental breakthroughs happen constantly! 







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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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In mentally processing the recent firing of the #BelugaGama...along with conversations with various members of the stoke crew...a few thoughts form a talk with Mike Perham got me thinking  a bit clearer about the experience. It struck me that the idea of having smaller kilns to compliment the #Pyranhagama was a good idea...turns out yes, for sure. So much has been learned from firing the smaller kilns (#GuppieGama 60c.f. and #BelugaGama 38c.f.). Be experimenting and learning a ton each firing I've come to the realization that firing the #PyranhaGama (125c.f.) is an extension of an ongoing learning curve...the kilns are all a part of a growing overall understanding. Back a few months ago...we fired the Beluga in an attempt to redux cool...but we were missing a recently added tight-sealing active damper which was installed about 8 feet up from the base of the chimney...just beyond the tapered end of the corbelling. Because we didn't have a complete seal on the kiln the first redux firing.. there was some draft and heat gain at the top temp end of the down-firing. I noticed a particularly pleasing array of soft yellows, purples and oranges that appeared on Jack Troy porcelain slip that was dipped (thin) on my Fireclay body. We fired a bit cooler that time...around cone 10. We've fired redux with a complete seal since then and have replicated the recent results(nearly) two firings in a row...no soft blushing of pastel colors....the big change this last time was a series of heavy stokes at the end to achieve a high temp a the side center of 2358F.  The big stokes resulted in 1.5 hours of reduction before the redux cycles (8-9 minutes between stokes with 3-4 minutes of relative clearing). The tight seal has yielded strong iron reds and intense orange flashing. Wanted to document this connection between firing methods as I'm planning to revisit a mild-draft semi-redux cool element to the next firing. Robert Boryk mentioned that he's seen the brightest flashing when he continued reduction cooling down to 1400F...we have been stopping at 1600F. I was also reading that Bernard Leach found interesting iron effects when introducing small bits of wood in the 7-800C range...roughly 1300=-1400 degrees...just before the pots loose their glow. This we'll try. I'm confident that we'll not jeopardize the quality of works as there's been no un-melted ash or any issues with any glazes or clay bodies as a result of our redux cool exploration. The clean out period within the down-fire cycles seems to be a key and I can thank Steve Johnson for bringing this amazing technique to my attention. We're firing the Pyranha in a couple weeks so I'll definitely be sharing our findings ASAP. Best, Trev

Hey Folks,
We just wrapped firing number six of the #BelugaGama.
There were a few new things going on with this firing that I feel are worth sharing.
Chimney:
We mudded the chimney base up to a newly installed active damper which is just above the corbleled section of the chimney....for down-firing. Huge increase in draft control. The active damper slot was left open throughout the firing and closed upon starting the redux cool sequence. 
For the first couple days of the firing, we kept the in-chamber active damper closed about 75%...that is once we started ramping up from around 300 degrees (we did a two and a half day pre-heat with active dampers open and passives closed). Full draw was used in the pre-heat...active damper open and passives closed.
Once we hit the "wall" at 2150ish...pulled the in-chamber actives and opened the passives on the back side of the chimney. Backpressure was maintained until then using the in-chamber active damper and was nearly replicated, with a slight loss of backpressure, when the passives were pulled. The kiln stopped consuming wood like a hungry teenager at that point...we burned through 2 cords of hardwood up until that point. One more cord brought us to top temps a day and a half later. It was a breakthrough to figure this method/draft-change out for sure. Finally, backpressure and temp maintenance/gain happened w/o a struggle ;)
We used a blend of Rock Maple, Ash and Fir this time around. The Fir, along with pretty dry wood, created a scenario where clinkers were no issue in the below grate section of the firebox. 
All in all, a smooth firing. 
Down-Firing: Steve Johnson ran the down-firing sequence...Kiichi Takeuchi and I helped. 5 minute redux burn followed by 3 minute clean out periods down to 1600....12 hours total. We're hoping for awesome results but have already taken steps forward in understanding and controlling the kiln atmosphere and temperature rise.
I'll post pics of the results in a couple days. I'm hoping some of this info is interesting to some of you out there. All my Best, Trev

 
Over the last couple months, things have changed.  A smaller kiln is in the works.  Smaller everything...amounts of wood, firing time, firing crew, prep time in general.  Quick turnaround....versatility will be a bonus! Fortunately, my friend and fellow potter, Stephen Rodriguez, has accrued a hefty stock of both soft and hard bricks over his thirty years or so of gas kiln building experience.  Between his bricks and fellow potter, Louise Harter's 1000+ Empires, a small kiln may be ready to fire in the next 4-6 weeks.  We've nearly completed the base layer of the kiln.
To begin with, the pad was excavated to level, layered with 3/4" gravel and a cinder block base was laid dry....two high/18'.  Then we layered the top of the cinder block base with 1/2" cement board.  Building a 2x4" frame, we cast the slab using a mixture of cement, 1/2" gravel, plenty of perlite and sand.  A pure concrete slab 3:2:1 Gravel/Sand/Cement was cast for the chimney base slab. The firebox floor was cast in a heavier perlite ratio than the chamber slab.  
We then cut and fit high alumina 5/4" shelves for the floor of the firebox and layered the chamber floor with 12x18" soft brick lintels.  For the firebox arch, Stephen free-styled a sprung arch curve, I traced and created a form using plywood and a jigsaw.  We cast the firebox grates with Mizzou castale and are now in the process of, having placed hard brick lintels around the permanent shelf posts, cutting and fitting hard bricks around the newly places hard brick 12x18" lintels.  
The form for the kiln chamber is a graduated 1:1 catenary arch.  The interior opens up to the center section and tapers to the tail...a 1:1 ratio is maintained throughout the chamber.  It was made from plywood cut to a gravity-formed archs and bound by 1/4"x10' strips of Ash.
The chimney will be 36x36" on the exterior to 6' height and corbel to a 14" square opening to 13'.
The firebox is roughly 1/3 or the chamber floor area.  Stacking depth is 6.5' with an average height/width of 42". Stackig space will be approximately 60c.f..
There's a lot of work left yet but we've taken care to make a solid base for the kiln.  The firebox has 3-3x36' grate slits and they are divided by the 9" depth of the castable grate.  
Hoping to fire in the next couple months..this summer for sure ;)​

Volume Math:
A 1:1 catenary arch has the equivalent of exactly 2/3 the area of a 1:1 square of the same dimension.
42" average height and width equals 1764square inches/inch. 
1764x12= 21,168"/foot.
1 cubic foot =1728
21,168/1728=12.25 cubic feet of stacking per foot.
6.5' chamber length x 12.25 cubic feet stacking per foot of chamber=79.625
At least 75 cubic feet of stacking will be available.
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7 chordsThe winter firing was a step into a new realm.  The elusive chocolate flashing emerged as a predominant kiln effect this time around.  Copper fuming was a complete surprise and a new direction of exploration for sure. A large Oribe green glaze...stacked up high in the front of the chamber provided volatilized copper to a number of pieces to the rear...gold and copper sheens developed on the raw surfaces of porcelaneous stonewares and porcelains. the changes made this time around include:
Stacking the front two rows with extra room above the pots...shelves in line re: stack height...allows better combustion and ash migration to the center/rear.
We fired with green wood included in each stoke all the way up to the last couple hours of the firing.
We used large split chord wood 5-7" split diameter.  2-3 heaping wheel barrows per stoke...every 20-30 minutes. 
Louise ran the overnight before the final day and stoked lightly with dry thinner wood to get cone 10 to start going over...this was a good prelude to a intense finish.
We loosened up the back a bit...still a little tight...but the back pressure throughout the firing created a beautiful color palette. 
The long and extreme stoke cycles were key here...so much depth in the surfaces...the green wood really brightened the colors throughout the kiln.  
Although there a number of dry pots around the tail...the kiln effects by far outweighed the losses...metallic asteroid blues with crystals and fumed glosses...oranges to chocolates...I'm so thankful and humbled by the beauty that can be attained through this process.  Cannot wait to fire again in June.
This firing was kinda slipped in as we had the majority of the wood split and there was half a kiln worth of pottery bisqued and ready...we had an over abundance of pieces that I held on to, from June, for the following firing.
Aside from the aforementioned changes, the firebox was modified...no pieces on the floor except to the very back wall.
Shut down procedure...approaching the finale'...I shut down the air in front and fed small sticks in to raise the temp( at center) to 2250...shut down included 3-4 full wheel barrows.. enough to fill the firebox to the top...the stoke door was blocked with wood.  Exit flue dampers were then closed and all air inlets were stuffed with kaowool.  Green was mixed in to the final stoke.
7 chords total, mixed hard wood and 1.5 of green oak.
This process never stops teaching and rewarding ;)

This June's firing was a mixed bag to the extreme!
Large pieces along the top of the kiln were covered in ash and responded beautifully....Mackenzie Shino with Redart, Raw Hawthorn Fireclay body and Blue Oribe thrived in the kiln's environment.
The tail was stacked a bit too tightly this time around...I have a clear idea of the results as they relate to temperature and surface effects....cannot wait for the next one which will be sooner than later.
We've been on a once a year firing schedule the last three firings and feeling the need to ramp up timing with next one...there's plenty of unfired student, fellow potter and personal work...enough the fill the kiln again and more....plus, we have the wood split and cured.
Thinking of simplifying the firing process this time around...I've invited various artists to participate and take ownership in different aspects of the process and I'm sensing that it's time to re-engage with the oversight and direction of namely the tail stack and final shift.  I've been inviting folks from the surrounding community and region to participate in the firing activities with the intention of connecting with both the established surrounding clay community and local residents that are completely new to the process. 
The community building aspect is important to me....the most important aspect...I believe that the quality of the work reflects the approach to the process and by incorporating others...new information and insight is gained...furthering the end quality of the work.
Next firing: skeleton crew and very small social gathering for the finnale'.  Back to basics ;)

This summer's firing was what I view to be our best firing ever.  I say this because the overall quality of the pieces was so varied and beautiful. The success rate was in the high 90's and I couldn't be happier with the level of quality. The results reflect the effort we've put in as a team of wood-fire potters.  The crew is evolving to comprise more professional potters than former students...a progression I hadn't anticipated but welcome.  Former students are absolutely still a factor...just nice to be working with potters that are fully committed to the craft.
The difference this time around had a lot to do with the stack. More pieces than ever before were packed into the kiln.  We've added a second firebox to one side at the center of the chamber...it's 2' deep and 18x18" high and wide.  Because we packed the kiln super tight...the secondary firebox aka the Nos....didn't have the jet fuel effect this time around regarding temp gain but the flashing to the back side was amazing.  Blown away by the effects of wood and atmosphere.  We're in a new chapter and could not be more thankful for the people that contribute! Next time around, more porcelain and bigger pieces..  Looking forward to the next big fire summer 2019.

I'm thinking this is our best firing yet.  Had a lot to do with the preparedness and crew for sure.  A good group of folks stoking and ample wood split, seasoned and stacked for efficient working.  A big change in the stack involved a secondary firebox in the bottom center on one side.  This was huge in that the flames were given a chance to completely combust...nice glaze melt and ash deposits toward the tail.  This firing yeilded great results that are featured on the summer 2016 unload page.