50 Cu/ft Sprung Arch Salt kiln with swing to the side door, built for Boulder Potters Guild in Boulder, CO September, 2022. We used Patriot Super Duty High Alumina #1 arch, Super 75s mullite for the floor, Kala Super Duty High Alumina, Seneca 60P, BNZ 2660 for the door, BNZ 2300 for cold face insulation/sub floor, and Seneca 60p self locking (chimney above damper) to build this kiln. The arch is 4.5” hard brick, 3” BNZ 2300, 2 layers 6# 1” fiber, chicken wire mesh, 1” of 80 lb scratch coat sanded with fiber stucco/3 gallon vermiculite custom mix for skin coat. We installed 2x 400k btu/hr burners to bring the kiln to cone 10 in 12 hrs firing time. Interior dimensions hold 3, 12x24 shelf stacks. 1/4” mild steel framing ranging from 3” to 5” give this kiln and swing door structural integrity.