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" Fake fire brick "  RSS feed

 
Posts: 47
Location: 48°N in Normandie, France. USDA 8-9 Koppen Cfb
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Just found this thread. Erica, a thousand million thanks, you have demystified the whole subject and given me food for both thought and action.

Refractory Mortar: Yes, it does like to take the brick with it when you dismantle, and that was after only two days. Do not ask me why I can confirm this during the build stage.

Lesley
 
Posts: 55
Location: Kansas City, Missouri, United States
homestead solar wood heat
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Erica said:
- Cast-refractory heat risers using perlite aggregate, or other methods to create insulation value, various thickness (1" to 2" have been successful in short-term prototypes but long-term data not available).

Has anyone used Geopolymers, specifically Low-Temperature Geopolymer Setting (LTGS), for the construction of their rocket stove?  Any short term or long term data? 

I am building a small j-tube 6" rocket stove with a 4.5" x 9" x 18" burn tunnel to heat riser ratio (1-2-4) as a prototype.  The box portion will be cast with LTGS.  The riser portion will be made from "Kiln Brick". 

The curing is done initially at ambient room temperatures.  Then a solar curing box can be used.

The wall thicknesses will vary from 1 1/2" to 2 1/2". 

The main ingredients of the LTGS are: 

kaolin clay
vinegar
KOH
sodium water glass powder
very fine slag sand
a very small amount of portland cement

I obtained the ingredients for the firebox mentioned above for about $30.
 
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Glenn Herbert wrote:I checked the specs and the customer Q&A at Lowe's, and these are not "concrete" as the title says, but standard firebrick. The 3000 degree spec is contradicted by an answer in the Q&A that says they are good for 2000-2300 degrees, which is good enough if not spectacular. 3000 degree firebrick are a specialty high-performance item, not likely to be standard at a consumer big box store. Kiln supply companies offer 2300 degree and 2600 degree firebricks, with the 2600 version distinctly more expensive.

The upshot is that this would be a typical material for a J-tube and heat riser. You might want full thickness firebrick (4 1/2" x 9" x 2 1/2") for the bridge over the burn tunnel, as that shape might be more durable than the equivalent in splits on edge; I haven't seen comparison tests there.



I am building a j tube rocket stove and saw this Lowes fire brick as well. I did not find the 2000/2300f rating. But if its suitable its easy for me to get and no shipping. Can you explain what you mean by full thickness bricks. or splits? much appreciated
 
gardener
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Location: latitude 47 N.W. montana zone 6A
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A full brick is 2.5" thick a split brick is 1.25"    Same shape just not as thick.  Insulated bricks are the best choice for your core away from the feed tube ,splits are desirable in the feed tube. Masonry supply houses usually have fire bricks and 50# sacks of fire clay.
 
Yeah. What he said. Totally. Wait. What? Sorry, I was looking at this tiny ad:
Rocket oven documentary pre-sale now available
https://permies.com/t/90306/Rocket-oven-documentary-pre-sale
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