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Post by josephcrawley on Nov 8, 2022 17:47:46 GMT -8
Your opinion, not mine. You are entitled to it, so am I. By the way, regarding what I said about the original question which started this discussion? Do you have experience with this cordierite material, not only an opinion based on what you think? Temperatures aren’t opinions, Peter. And these are well-documented temperatures. You are a master pontificator. Your ideas may have merit but the constant verbose barrage of armchair pedantry is insufferable. Please self moderate. |
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Forsythe
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Post by Forsythe on Nov 8, 2022 18:18:04 GMT -8
Temperatures aren’t opinions, Peter. And these are well-documented temperatures. You are a master pontificator. Your ideas may have merit but the constant verbose barrage of armchair pedantry is insufferable. Please self moderate. wow. |
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Forsythe
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Post by Forsythe on Nov 8, 2022 19:37:50 GMT -8
I apologize for any inaccurate information I’ve posted, and I readily admit when I’ve been wrong and needed to be corrected, myself. But I make no apologies for insisting that the veracity of the information shared on a topic like this —with such thin margins for safety as this— is more important than the egos sharing it. I would encourage anyone to take a good hard look at what’s more important between the two.
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Post by peterberg on Nov 9, 2022 1:55:00 GMT -8
Thanks Joseph, being a native speaker has its merits.
As an aside: the kiln shelves are'nt in the realm of cheap refractory, it's cost is over double the price of high grade firebricks. Nothing is cracked, no matter how hard I pushed the little shoebox. In all my years as an amateur autodidact heater mason nothing is exploded or caved in, so the safety margin of the used materials seems to be adequate. Also, as said before, the UL listed Liberator rocket heater contains the same type of kiln shelves for the firebox liner.
I will not be involved in a heated discussion about who's right and who's not. Let my results and track record of 40 years involvement with a plethora of different refractories speak for themselves. To everyone who think knows better: please, let us all see that you are the better heater designer and builder. And not just another armchair theorist.
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Forsythe
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Post by Forsythe on Nov 9, 2022 2:34:04 GMT -8
I will not be involved in a heated discussion about who's right and who's not. Let my results and track record of 40 years involvement with a plethora of different refractories speak for themselves. To everyone who think knows better: please, let us all see that you are the better heater designer and builder. And not just another armchair theorist. Odd, don’t you think, that you’re the only prodigious heater builder who’s stuck around this place, and you’re also the global moderator. That, alone, speaks for itself, peterberg You haven’t involved yourself in a discussion of who’s the better heater builder. You’ve actively cultivated it. |
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Post by peterberg on Nov 10, 2022 9:35:19 GMT -8
Odd, don’t you think, that you’re the only prodigious heater builder who’s stuck around this place, and you’re also the global moderator. That, alone, speaks for itself, peterberg My knowledge of the English language is limited, I'm in the dark what you mean exactly. Explain, please. |
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Post by fiedia on Nov 10, 2022 11:12:04 GMT -8
You are wondering if cordierite will withstand DSR3 after-burner temperatures. Peterberg told you he did not measure temperatures inside his DSR3 up to now. The highest temperature he could measure inside a batch box heat riser is around 1200°C. Forsythe warns that one can reach up to 1500°C inside a wood fire kiln. Are you still wondering if you should try cordierite or not ?
My knowledge is limited to experiments with two 5” batch rocket prototypes including temperatures I measured with the help of 3 thermocouples at different heights inside the HR. I am quite confident that under normal use, your DSR3 temperature will remain below 1280°C for the following reasons.
I tried to measure the highest temperature I could reach inside my first prototype (an ultra light batch rocket made of vermiculite, aerated concrete and no bell, i.e. low thermal inertia). I managed to reach 1000°C and above for a short period of time. It results in lots of dark smokes and smells. You can see flames above the HR. It means that full combustion is not achieved (my avatar shows the flames out of the HR).
On my second prototype (bricks and bell), every time HR temperature went above 900°C it produced dark smokes. On Peterberg advice, I reduced the primary air inlet cross section and fumes went clean. The optimized solution was to keep HR max temperature between 600 and 700°C during the whole run. Details Here.
My conclusion is: under proper use, you will not get temperatures above 1280 °C in your DSR3. Peterberg’s designs are optimized to get a clean steady burn, not dirty maximum temperatures. If you keep your door closed and air inlets as specified, cordierite should withstand DSR3 temperatures.
Now remains the question of chemical etching pointed out by Forsythe for superwool and light refractory bricks. Does it apply to cordierite ? |
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Post by foxtatic on Nov 10, 2022 12:26:34 GMT -8
You are wondering if cordierite will withstand DSR3 after-burner temperatures. Peterberg told you he did not measure temperatures inside his DSR3 up to now. The highest temperature he could measure inside a batch box heat riser is around 1200°C. Forsythe warns that one can reach up to 1500°C inside a wood fire kiln. Are you still wondering if you should try cordierite or not ?
I appreciate Forsythe taking the stance of absolute caution because of what is possible. I also appreciate that Peterberg has taken batch box temp measurements, pushing it as hard as he could and showing that 1200°C was the highest temp he could achieve. I believe this is a closer context to a DSR3 than a wood fired kiln is. And since Peter confirms his use of cordierite in the DSR3 core I am trying to build, I will use it. |
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Forsythe
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Post by Forsythe on Nov 10, 2022 17:25:24 GMT -8
You are wondering if cordierite will withstand DSR3 after-burner temperatures. Peterberg told you he did not measure temperatures inside his DSR3 up to now. The highest temperature he could measure inside a batch box heat riser is around 1200°C. Forsythe warns that one can reach up to 1500°C inside a wood fire kiln. Are you still wondering if you should try cordierite or not ? I appreciate Forsythe taking the stance of absolute caution because of what is possible. I also appreciate that Peterberg has taken batch box temp measurements, pushing it as hard as he could and showing that 1200°C was the highest temp he could achieve. I believe this is a closer context to a DSR3 than a wood fired kiln is. When the topic was first broached here, we were discussing simply "cordierite" and not "kiln shelves." (I know this may sound nit-picky at first glance, but it's an important distinction.) This next build I mentioned with the vermiculite board DSR3 will be different. I plan on only using the board as the outer housing. The firebox will be lined with fire brick. The floor layer, shelf, and top layer will be cordierite. Because of its negligible thermal expansion, cordierite is one of the most studied technical ceramics in the entire Al-Si system. Over the last decade or so, there have been a number of researchers reporting on the low-temperature sythesis of cordierite for a huge variety of applications beyond simply kiln shelves, produced at temperatures as low as 1000ºC, like this one, this one, and this one, among countless dozens of others. (The interest in forming cordierite at lower temperatures has been intensive, because lower temp synthesis of the material makes the products substantially cheaper than the older, far more expensive method of sintering alumina, talc, and silica at higher temperatures for longer soaking periods at temp. Cheaper cordierite has wide application for everthing from heat sinks on the reverse side of solar panels, to satellites component housings, to domestic baking stones — and everything in between which undergoes rapid heating and cooling cycles.) Because of this, the majority of cordierite products now produced are not the high-temperature, talc-synthesized variety... and the cheaper, more widely-available stuff in-general appears to have lower thermal tolerance than the kiln shelf variety. Also because of this, I've cautioned against "cordierite," writ-large— and in every instance with the stipulation that cordierite's thermal tolerance depends on the starting materials composition. And this is also why I mentioned earlier in the thread that the highest achievable temperature of a natural-draft wood-fire is critical info when it could influence your purchase decision between two types of products such as this. Personally, I experimented with 3 different brands and thicknesses of cordierite baking stones I was able to purchase relatively inexpensively in bulk: used as the roof of a vortex-style firebox beginning in the fall of last year. At or immediately following peak burn, they all cracked and failed. The first of them completely collapsed in on itself and sent a shower of embers around itself. Luckily, I always opt to test materials outside, away from combustible surfaces. The sintering temperature quoted by 2 of the manufacturers was 2100ºF (1148ºC) and 2200ºF (1204ºC), which comports with the body of published research findings above, regarding this newer, low-temperature synthesis of cordierite. I didn't post anything about those experiments at the time, A) since I was relatively new to the forum at the time, B) since Gadget had already reported the failure of cordierite baking stones in a J-Tube in this thread, C) since Trev had already reported the failure of kiln shelves (of unknown composition) in his Vortex stove thread, and D) until yesterday in this thread, Peter did not know whether his own kiln shelf was cordierite, cordierite-mullite, or mullite. Later, I tested those same brands of cordierite baking stones after coating them in ITC-100 and ITC-296A (as more of a test for the dual coating than of the shelves themselves) and those ITC-dual-coated shelves survived unscathed. ...So if you're building a DSR3 with the same exact materials, bell configuration, firebox size, chimney stack height, and fuel type that Peter uses, you'll probably be okay to use kiln shelf cordierite. If you deviate in any way from making an exact replica of Peter's total heater system, I would exercise caution and try the thing out-of-doors first before building it inside your home. |
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Forsythe
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Post by Forsythe on Nov 10, 2022 23:37:52 GMT -8
Odd, don’t you think, that you’re the only prodigious heater builder who’s stuck around this place, and you’re also the global moderator. That, alone, speaks for itself, peterberg My knowledge of the English language is limited, I'm in the dark what you mean exactly. Explain, please. It means that your hostile, unreasonable, and belittling attitude toward valuable sources of information— all those coming from anywhere other than yourself— has chased away virtually all other knowledgeable contributors to the forum, including Matt Walker, Max Edelson, the wider masonry heater community at large, and countless others… even the forum creator, Donkey Mobert, himself, doesn’t bother posting here anymore. Have you never wondered why those folks don’t bother to participate here after the condescension with which you’ve treated them and the info they had to share? Have you never wondered why repeat regular member participation in the forum is so low? The kindness, grace, and Saint-like patience of regular folks like Trev ( Vortex ) —despite the way you’ve spoken down to him over his invaluable years of posting here — is the only reason I still bother logging in, myself. |
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Post by fiedia on Nov 11, 2022 0:15:09 GMT -8
Forsythe, where did they all go ? You have another forum to advise ?
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Post by foxtatic on Nov 11, 2022 5:10:23 GMT -8
Without quoting your whole post, I will thank you for a lot of great points and providing that depth on why you have the conclusions that you do regarding cordierite. Goes to show you cannot take any general material characteristics for granted. Makes sense that there would be a push for cheaper, lower temperature cordierite for baking stones since a home oven gets nowhere near hot enough to need a 2000º+ rated material! This is what makes it essential to get specifications directly from the manufacturer of the specific material you are looking to buy. In my case, the manufacturer of the kiln says the shelf is rated for 2350ºF. I very much do plan to test this thing outside first. |
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Post by josephcrawley on Nov 11, 2022 5:29:13 GMT -8
It means that your hostile, unreasonable, and belittling attitude toward valuable sources of information— all those coming from anywhere other than yourself— has chased away virtually all other knowledgeable contributors to the forum, including Matt Walker, Max Edelson, the wider masonry heater community at large, and countless others… even the forum creator, Donkey Mobert, himself, doesn’t bother posting here anymore. Have you never wondered why those folks don’t bother to participate here after the condescension with which you’ve treated them and the info they had to share? Have you never wondered why repeat regular member participation in the forum is so low? The kindness, grace, and Saint-like patience of regular folks like Trev ( Vortex ) —despite the way you’ve spoken down to him over his invaluable years of posting here — is the only reason I still bother logging in, myself. I've been a member of this forum for quite a long time and I have seen Peter very occasionally be short with posters. Usually they have either badgered him with questions that could easily be answered by the information clearly presented on his website or they are armchair theorists telling him what is wrong with his design. He is a kind and largely patient person who has generously shared his many hours of research with this community. He has made no effort to discourage others from researching alternative designs. In fact he has encouraged these efforts. He is a moderator on this site because the founder(donkey) made him one. |
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Post by hallinen on Nov 16, 2022 15:33:47 GMT -8
I’ve been reading this site for years. I appreciate when people are critical about designs and materials, but I don’t like to read anyone putting down Peter in such a rude fashion, no matter how smart they obviously are. I enjoyed the thermometer debate, until it got snippy. I love learning about refractory materials. I am fascinated by Peter’s and others combustion analysis after design tweaks. Please don’t turn this into one of those mean spirited social media sites. I appreciate concerns for safety. I hope moving forward users pause before posting words that feel like an attack.
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Post by ronyon on Nov 21, 2022 11:22:44 GMT -8
I am an armchair theorist, and I have found lots of patience here along with occasion impatience.
Being entirely ignorant and benefiting from lots of free information, I am grateful for the information and take no offense at the occasional Qx ptone.
The best challenge to the orthodoxy expressed here is active expirementation.
Matt Walker has repeatedly done things that he was told were not possible.
He did them and tested them,shared his results and thereby pushed the technology forward.
I don't recall him getting upset with anyone or questioning their standing to speak,though I may be idealizing him on this point.
Even if that is the case, why not pursue this ideal?
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