Damper, passive air, & chimney caps?

[gary navarre]

Hey Folks,

 It looks like I'm gonna inherit some of this kiln project in downtown Detroit through no fault of my own. Billy and Duke and a few other guys did most of the work until now but Billy needs to go to Central America to help his daughter deliver a baby so I guess I'm gonna throw in with whatever knowledge I can find to add to what I learned on my own. We can remove the arch forms now so the flooring can be set and the stack can be built. There's the rub because the bricking needs to fit the jagged curved edge of the chamber. Billy said something about a vertical sliding damper at this juncture but I'm betting a kiln shelf that size could cost about $125 or more and it sure would take a beating after a few firings. I did some dry setting just to visualize better where bricks could sit for the stack base ...

http://public.fotki.com/GindaUP/ca/kpap/ba/chimney-base-1.html 

 

 In my last kiln I had a sliding 12"x24" damper at about 5' up the stack with one small passive damper hole below and a couple more above up the stack. At 18' I had a chimney cap. After a few firings the shelf broke a large chunk off so it would still seal but eventually that slice broke too. Due to the length of the chamber Billy is talking about a shorter chimney would work fine, enough to clear the metal roof. With enough people to keep the fire going the chimney could be left open and the draft slowed with the passive air and some sort of shutdown/soaking damper to hold the heat.  I have seen some pretty stubby stacks with just a chimney cap on Japanese kilns, maybe Shiho Kanzaki's. I've also seen the rows of passive damper holes on the CCS VanGilder Manibigama in operation. I'm beginning to visualize a bunch of passive holes (soaps) along the base with a couple higher up to spy into the chamber tail. The taper could start at about the top of the chamber arch on up to where Billy figures will be enough height to start. We could put a sliding horizontal damper somewhere above the arch and/or make a ladder up the roof to manipulate a chimney cap to close the kiln after firing. We could have some sort of lever mechanism welded up to move the chimney cap easily from the ground so if the roof gets hot nobody has to climb up to the top of the stack to set the cap when we shut down. If some of you folks could lend a few shots or thoughts of how you deal with the whole Anagama chimney cap sliding/passive damper usage I'm open for suggestions.

 I wanted to go downtown to sort more brick early but the weather says more rain and two big events, The Belle Isle Grand Prix and a country music festival, are gonna make traffic crowded. The kiln is about 6 blocks from the South end of Belle Isle so the engine noise will be quite evident and the air won't be helped any.

Gary Navarre
Navarre Pottery
Navarre Enterprises
Dearborn, Michigan, USA

http://www.youtube.com/GindaUP
http://public.fotki.com/GindaUP/