Hi All; So... my plan of using all castable refractory to remake my core has gone by the wayside ! life has gotten in the way again. instead of having all summer to carefully rebuild,... i have 2 weeks to get it done , before work goes to 7 days a week with 12 hour days, out of town ! Not having the castable on hand means that i am using firebrick instead, also not having the time to hunt up more of the super lite firebrick i will mostly use my stash of heavy ones. My original core, was a poured core using matt walkers mix of fire clay,perlite and a little refractory. The heat riser itself and the end of the burn tunnel all look as good as the day i poured them ! The problem for me was at the feed tube end not being able to hold up to my ramming wood into it , despite patching several times and painting waterglass on the walls, by spring instead of a nice 7" square hole I ended up with a hole the size of the 5 gal barrel that i had used as a feed tube !(had to be partly covered to prevent backdrafting ) Worse than that was when the roof of the burn tunnel at the feed tube end started falling away! Amazingly even with all that i still got barrel top temps over 1000 and no smoke out the chimney! During the teardown I discovered that at some point a hole had burned its way thru the roof of the burn tunnel and was venting into the 55 gal outer barrel ! And it still WORKED ! After a long winter in the green house i pulled apx. 2 gal of super fine fly ash from my collection point ! None was built up at all in the horizontal piping! I couldn't be more happy with how this stove works, anybody that burns wood should be TOLD about them ! Following are pictures from the tear down .
One of the many thing that make this stove so neat is being able to reuse all of your building materials ! I carted the chunks of cobb out the door and placed them on a tarp. The pieces of cast core were placed in 5 gal buckets and placed out doors, where it is conveniently raining on them . In the last picture you can see i used brick to form up my base, then i reconstituted my cast core and made a 3" thick pad to start construction on.