castable refractory, inswool, and durock

[stovol]

i used the aforementioned materials.. contraption is 25 inches tall and 16 inch length burn tunnel.. width of the durock (1/4 inch ) held together with some high temp caulk, then an inch of ceramic blanket, taped some cardboard together and mixed up the icf... it started as an 8x8 heat riser 24 inch length of the durock... after adding the high temp blanket and insulating castable i ended up with a five inch system.. this sucker burns like hell.. the icf really does hold the heat in..

kastolite 26 55lb bag $40

inswool ceramic fiber blanket
8# density 1" thick... $60

Durock $9

High temp caulk $4

i used about a third of the icf, a fifth of the inswool, half the durock, and a negligible amount of caulk.. my cost on this build is an estimated $ 40.. i built another stove for a buddy from an ammo can (the green army ammo boxes) He wanted a portable cook stove for camping.. its drying now .. pics of that later.. and i still have about five lbs of icf.. a buttload of the blanket.. so all in all i'm deep into this now and still only out $120(with lots of material left over).. thats two nights at the bar for my wild buddies! the buddy i built the ammo can stove for is a machinist so i'm having him make a sleeve for the top .. 14 inch plate will sit on top of it.. and an 11.5 inch circular skirt .. just the right size for a cast iron skillet.. you really must use a skirt to capture heat for cooking

i plan to get some plistix 900f or itc 100 to dab onto the burn tunnel... i will also buy some rigidizer for the blanket... i should then be able to form the inswool into almost any shape.. once it hardens the icf will be much easier to apply... the thing weighs about 35 lbs so its easily moved.. thanks everybody! i really dig what you're doing .... just wanted you to see that the materials used is definitely an option.. once i priced furnace cement and perlite i decided i might as well see how the high tech stuff performs! i'll prob be able to melt aluminum once i line it with an infrared coating! JK Good luck everybody!

Build it! and they will come

[stovol]

cant figure how to put more than one pic in a post

[stovol]

last one

[stovol]

i received my infrared laser thermometer in the mail today.. 50 to 1 spot ratio... was up to 1799 degree F in about 20 min starting with some small cardboard pieces and about one half pound of wood... exit temps were steady at about 950 to 980.. avg temp was around 1590 in the chamber.. 1100 to 1200 range as it turned up the heat riser.. exit temperatures were in the 1000 to 1100 range (higher) when it was smoking? i.e. when i adjusted wood or intentionally choked it

[pinhead]

Are these temperature readings inside of the burn chamber/heat riser or on the outer surface? I'm curious how well this combination of materials insulates...

[stovol]

outer pin, the flexible high temp caulk was no good tho... it needs to be a rigid structure because the castable concrete is not that strong.. i move it around alot.. i replaced the board on the bottom with an inch thick piece of insboard today.. 1900 degree... then used construction adhesive to put another piece of durock on the bottom.. i patched a few places with 2 parts kastolite and one part satanite.. lit it up and in ten min had 1456 degrees farenheit read with my thermometer just behind the entrance of the wood feed. that is where the hottest temps always are .. 1655 in twenty min.... right now its been burning 34 minutes... 1751 max temp in burn tunnel ... 1250 to 1350 at the turn to the heat riser.. i just stand above and point the laser straight down... and exit temp is 800 to 900f.. the insulation factor is superb.. my thickness on the refractory is about 1/4 inch with one inch ceramic blanket behind... just read 1856... my thermometer can capture the maximum read temp thru an entire scan.. it is averaging now, after about an hour of 1650 to 1700 in the burn tunnel.. just added a peterburg plate to it!

[Donkey]

Remember, those laser thermometers measure black-body radiation.. That is, the SURFACE temp of whatever yer pointing it at.
Yer getting readings of between 1600 and 1700 (at burn tunnel) on the SURFACE of same, NOT from the gasses inside, which could be hotter yet.

[stovol]

hey donk, great board and thanks for everything you're doing! i bought the thermometer after researching for only a few days... that was enough for me to realize that a testo or bacharach would have to wait.. my next best option was an infrared thermometer with a laser pointer... so as far as i understand, the laser does not read the temp.. in fact, i can turn it off and still get temp readings.. it goes to 2492 with a 50 to 1 spot ratio...1C or 2.5f degree of accuracy ... it reads a .7 inch cross section at 12 inches..larger from farther away... $174.. thing is i cant get a reading at the top of the burn tunnel due to the shape of the stoves... i can read the bottom about three inches back if i move the wood out of the way... no matter how hot it gets tho... exit temps are always about 900 read about an inch from the top at all four sides of the rectangular heat riser, sometimes a 1000 sometimes around 800.... the turn from the burn chamber can be anywhere from 1000 to about 1350...read from overhead shooting down.. the distance from the back of the feed tube to the turn up the riser is about 6 inches on top.. 11 inches on bottom... it cools off 500 degrees in that 6 inches as the flame hugs the roof of the burn tunnel.. . im reading basically the high temps of the coals about three inches back on the bottom.. other temps are readings of the castable surfaces..