Will concrete blocks “explode” if you make a rocket stove out of them?
Here’s some of the feedback I got.
by Leon Pantenburg
The most popular SurvivalCommonSense.com YouTube video so far showed how to build a rocket stove out of bricks for about $6. It has gotten, to date, more than 1,500,000 views. Imitation being the most sincere form of flattery, (he comments, with a trace of irony) there are several other successful posts, using virtually identical materials and pattern.
The original idea was to spread this low-tech method of boiling water in the aftermath of a disaster. I built the original stove out of concrete bricks because they were the cheapest at Lowe’s. But many different brick materials can be used.
Here’s what the readers think about it:
From Hilltop Homestead: “I understand you are speaking regarding to survival. Many people however, would like to make these for regular or semi regular use. I have always been told that you need to use fire bricks for safety.”
Several others commented that the concrete could “explode” if heated too much or would crumble after use.
So I asked an engineer and chimney guy, and they both said there should be no problems.
Then recently, another chimney guy named Greg Garrison weighed in. Here are his thoughts:
“I spent many years in masonry construction. Chimneys and fireplaces were our specialty.
“Fireplace construction uses firebrick for the firebox and ceramic flueliners to carry the heated air out of your house.
It would take very intense heat for a concrete block to “explode.” (Think cutting torch temperatures). Over time,they will deteriorate with heat. As mentioned below, the yellow fire brick, or chimney brick, is the only brick to use. They do not absorb heat. Not sure on the cost but it would be money well spent.
“If you are just occasionally using a rocket stove, you should be OK with regular brick/block.
“Also, if you are building a “permanent” rocket stove, don’t use regular brick mortar for the fire brick. You will need a small bag of “fire clay.” You mix with water just like mortar.
“I built my “rocket stove” a while back and absolutely love it. I am going to incorporate one into my new outdoor firepit/grill.
“I probably “overbuilt it”. I had a neighbor give me about 400 firebrick last fall and was wondering what to do with them. (I only used about 30 of them).
“I am amazed at the efficiency and the heat it produces. High heat and very little ash.
“I live outside of Cincinnati, in the country, and have all the fuel I need. Don’t worry about the flue liners unless you are building the stove within a structure and need to vent outside.
“I am sure you get a lot of “tips” but I think in this case, simple is better.”
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