shane mickey on sat 18 aug 07
hello group,
wow what a difference a day makes, our internet service was down and i missed all these cool kiln discussions! so here is my two cents. propane works off of high pressure and nat. gas is low pressure. for the best chimney i mortar the bricks with air setting mortar, then apply a mix of portland cement, sand, fireclay to the outside of chimney to help with airtightness, then use angle iron to hold tightly together. I do not believe in jackets over outside of chimeny for airtightness as it still leaks on all four sides of the metal or whatever you use, durock is the worst as it dries and becomes porous itself and also likes to warp outward, thus creating a gap in the middle of the board hence more air, this leads me to the kilns design topics. Micheal i admire your approach, but dont give advice that is that complicated! why on earth do we need to build kilns so technically difficult? glass blowers build their furnaces like that cause they are always running and they have gas
bills that are $2000 dollars a month! a typical hardbrick gas kiln is like $150-$200 x 10firings a year is close to what a glass artist pays in a month. keep it simple is a good rule. do not stack bricks on their sides (2.5") thats a weak structure, they always start to lean towards the interior of the kiln, bad design. use those large bricks just like regular brick, it will mean many less seams leading to your insulating layer and that will cut down on heatloss and soda penatration. k20s are ok for the outside but they do tend to be weaker. as to glazing the inside of kilns.. NOW that is just plain stupid! i remember the threads about shinos being used inside soda kilns. anyone who has put a shino in a soda kiln knows what it looks like, very little color, bleached to the point of little glaze left, a high alumina matt? well may hold up a little longer, but still, WHY? I have seen all kinds of coatings tried, in the end they all start to break down, whats the point. AT one
time we potters use to relish the time when the kiln became, "seasoned" what happened to that idea? i know of salt/soda kilns made out of high duty brick that are 12 years old and have been fired at least 6-8 times a year and they are still being fired!, how much longer does a kiln need to last? a standard size kiln runs around 5-7K in materials. if your prices are the norm yoiu should be getting around $5K worth of pots out of that kiln, who long would it take for that kiln to be paid for realistically?, no more than two years. enough of the complicated stuff, build the kiln simply, get firing, and get out and sell those pots! dont waste time building rockets, enjoy the process of firing and making, and oh yhea selling too.
shane mickey
kiln design services
_______________________________________________
Join Excite! - http://www.excite.com
The most personalized portal on the Web!
| |
|
