In this week's Noborigama update, we finally get to see the arch forms take shape!
After the walls of the first chamber were basically finished and the (very tall!) cinderblock base for the back chamber was set in place, we got our arch forms balanced on top of each section with bricks and wood shims. Our forms were purposefully cut an inch or so shorter on the bottoms, so that once the arch bricks were laid and the keystone brick was in place — we would be able to take out the shims and drop the plywood arch form out, while leaving the bricks suspended.
The span of the first chamber's sprung arch had all of us feeling a little nervous — technically the dimensions are a little outside of the handy A.P. Green Refractories brick and arch guide. Nonetheless — we sauntered on, broke up into two teams, and laid all the bricks for the arches in a few days time.
Arch form set in place for the first chamber.
Measuring the skewback and brick angles needed for the sprung arch.
Skewback bricks in place, and sprung arch almost finished.
Fortunately, the sprung arch was long enough that we were able to use straight bricks (instead of No. 1, No. 2, or No. 3 angled arch bricks) for the entire arch except for the keystone brick. We really only had straight bricks and No. 2 bricks available to us — sometimes you have to work with what you've got!
The catenary arch used the few No. 1's we had laying around, and the rest was laid with straights and careful sairset refractory mortar application. We went through a lot of sairset mortar during this week.
Catenary arch form for the back chamber set in place on top of cinderblock base.
Laying the bricks on top of the plywood catenary arch form.
After much hassle (and mortar) we were finally ready to get the keystone bricks into place. Next week's Noborigama update will reveal the satisfying keystone bricks!
Zeynep Uner is the current kiln and wheel repair apprentice at Bracker’s, working directly with David Sturm (the head tech) on repairs large and small. She has been repairing kilns for approximately 3 years now, and has been absorbing everything she possibly can from David’s 30+ years in the field.
Zeynep enjoys atmospheric firing, taking film photos, and throwing on her old Brent kick wheel.
