testing the temperature inside a RMH

We ran some test cones in the RMH in the house here at base camp last night after doing some more work on it, and Paul wanted the results posted

The two melted cones are 022 and 017, the unmelted are 07 and 5. Cone 017 melts at 1357 degrees. The container is a sardine can that is quite degraded at this point.

Jason : This really really needs to be a New thread and not just stick on the end of a long and old Forum thread as a Thread Extension !

This really needs to be seen more widely ! My Grandmother would say ''Don't hide Your light under a bushel basket !''

For the good of the Crafts Big AL!

Yay, meaningful testing! The next question is, exactly where were the cones sitting in the RMH? And for those not already familiar with the particular unit, what are its basic specs?

The next test could be a few of these trays mounted at strategic points in one burn, to get a temperature profile started. (Though we already know the basics of that from seeing where metal liners have corroded first.)

Jason, when you say 1357 degrees. You mean farenheit or celcius? If celcius, that's hotter than anything previously recorded. Which is the 1200C° range.

Satamax Antone wrote:Jason, when you say 1357 degrees. You mean farenheit or celcius? If celcius, that's hotter than anything previously recorded. Which is the 1200C° range.

Well, did my search.

http://www.ceramicstoday.com/cones.htm

So 017 is melting at 1376F° so that's 747C°

And the 07 didn't melt, Which is 1803F° or 984C°

IIRC from discutions with the guys at Donkey's. The last volatiles burn around 900C°, so that's 1652F°. So a Cone 010 would be a good indictor if it melted.

HTH.

Max.

Really cool testing, which begs a few questions / more details.

Was the cone test conducted on the standard 8" J-tube Ianto cob rocket? I.e. like the one just built at the innovators gathering?

What type of fuel wood species was used for the burn? Was the wood fully dried to the typically recommended low (approx. 15%) moisture content by chance?

I assume the cones were placed in the central area of the base of the heat riser?

OK, I assume the cone test was done on this specific portable RMH, so disregard my former question.

Allen made a great suggestion to start a new thread for the RMH temperature test data. I'll second that, and it would be handy for the new thread to be made "sticky", assuming the forum software is capable of such.

Also, may I suggest including and testing more stoves, with all of data from each RMH put into the same thread, along with the build specs. of each stove, maybe even photos too.

What little I know....

The cones were placed at the far back of the wood feed - on the floor of the wood feed. So this is probably the coolest spot of the wood feed. The hottest spot would be about twelve inches above this point (depending on a lot of variables).

Based on the results, Ernie thinks we are seeing temperatures pushing about 4000 degrees F at the hottest point.

W.o.w. : Just for a little more clarity : I have seen charts that give both the ignition temperature of a given flammable gas and beside it the Temperature the given
gas burns at, I have not seen a chart like that lately and often end up guessing if the temp posted is Ignition or steady flame front temp And definitely we need to
always label our ºF and ºC

So we are saying that wood burns at 3400ºF,but some of the Wood gases themselves burn hotter ?! We are all living in interesting times ! Big AL

Another tidbit of info: the cones require 20 hours of constant temp to test the temperature. These were subjected to a two hour burn that had a lot of temperature change.

Actually, that is not true. Cones are designed to measure the heat work done on pottery and other ceramic items being fired, and it would be rare (presumably only in industry where huge items are being fired) to "soak" the kiln at top temperature for 20 hours. An hour or few is the most commonly done for pottery.

There is a chart for Orton cones giving the temperature equivalent for various rates of temperature rise at the final stage, and slower rates will make a cone bend at lower temperatures. This is relevant, as the pots are also affected by the rate of rise, so cone numbers are more meaningful for ceramics than raw instantaneous temperature numbers.

From the way cone 017 in the picture is bloated, it got way past that, but not close to cone 07 which is still perfectly straight. I would guess something like cone 010, which would be around 1640 F for the self-supporting cones you have. This is an estimate and the actual could be between 1500 and 1700 F.