Question about building a bigger Missouri Design Masonry Stove

Masonry stoves are complicated. I have never used one, but, came close to buying a Tulikivi for my house some years ago. I studied up on them quite a bit.
I would be very hesitant to modify one of these stoves, I think you might be making a mistake if you modify it. I hope you can find an expert to give you the real scoop.

How cold does it get where you live down in Patagonia?

That is some cold weather! Would be good for a masonry heater.
You have no gas network. Can't you get propane? Up here in America, I have a 500 gallon propane tank, when it gets low the company sends out a truck and refills it. Works just like natural gas, is a very good source of heat, I also use propane for my stove and water heater.
Can't y'all get propane down in Argentina?

Simonkenton said:

That is some cold weather!

Click to expand...

-20 C = -4 F.

zrafa,

Thomas Elpel lives in Montana, USA, and wanted to build a Masonry heater, too. The only plans he could find were those Missouri fireplace plans so he built a few masonry heaters using these plans. He made this short video. But he sells a longer more detailed video of his building process (like US $20).


The Missouri design is what is called a Russian fireplace. The channels run above the firebox horizontally back and forth and out a top flue. The MHA (Masonry Heater Association) also sells simple plans. They mainly follow a Finnish design called a contraflow. In this design the channels run up and down. There are usually 2 channels but there can be more.

The president of the MHA, Dan Givens (not him in video), built this large masonry heater and used Alaska river rock to finish it. They are burning 100 pounds of wood per firing - so it's a big one. I am not sure of the internal lay out. But the channel starts to one side of the firebox and than I'm not sure where it goes. Maybe both vertically and horizontally.

This appears to be a bigger design than the Missouri or contraflow designs. If it was me, I would call Executive Director Dick Smith at MHA, (520) 883-0191. He could direct you to a mason who you could call and run your questions by. You could tell them the space you are trying to heat, your house layout, etc...

Too bad about the propane costs in Argentina, propane is cheap here in America, it is similar to natural gas.
byQ, that is a fascinating video. Like I said, some years ago I studied up quite a bit on the Finnish Fireplace. The Finns did a lot of research at the Technical Institute following WW2 and they learned that the hottest fire is developed with a vertical flame path of about 4 to 5 feet. They found that a vertical flame path this high produced the highest heat, and they are getting, as best I recall, about 1,700 degrees in that fire box. Such a hot fire burns the wood right up and leaves very little ash.
This is the design principle used in the Tulikivi Finnish Fireplace.

So, it is interesting to me that this guy in the video has a vertical flame path of only about 2 feet. I don't know which is better, obviously the guy in the video knows what he is doing.



A Tulikivi Finnish Fireplace. Tulikivi sells about a dozen models.

I want to build a Masonry Heater, too. I've got part of a house foundation done, and as soon as the slab is poured I can start constructing a masonry heater (MH). The spot where the MH sits must have a deeper slab (like .4 meter).

I live in a great place to get stones/rock, the Gem state - Idaho. I drove north up to Salmon, Idaho. I would drive around the corner and their would be another mountain of stone. I'ld be thinking, 'wow there are 10,000 red masonry heaters, I'ld round another corner and think, there are 10,000 green masonry heaters.....' But for my heater, I just went out to a rock quarry and for $20 they let me load up my pickup with their discard stone. Looking at a pile like this can be daunting. Which stone do I collect?



I try to picture a stone fireplace from what is available and than I start collecting. I found this rock interesting - salt & pepper granite in the right sizes for layering. Also I found just enough wood-looking and green rock that had 90 degree sides to use for cornering, so I grabbed some of these, too.

Simonkenton,
I would like a Tulikivi but they are expensive. If I win the lottery.......looks like I'm going to have to take matters into my own hands.

Thanks begreen,
zrafa, you said something about having to use gas/oil to heat your water. I heard a couple masons talking and they said they are getting more and more orders for masonry heaters that have coils in them for heating water. So, you might want to ask about this, too.

zrafa,
Thanks for the video. I hadn't ever seen that one. I went to a masonry heater build in Las Vegas, Nevada, last year. They are meeting again this year to build a bigger contraflow type heater - World of Concrete, Feb. 3-6. Last year, it was a small contraflow type of heater. I took a bunch of photos. I can PM them to you if you want. Although the design is different there are some basic facts about building a masonry heater,

* there is an inner part called a core - usually made out of fire bricks. However, most tulikivi's use soapstone, and the core kits are made from refractory cement.
* expansion of the core must be realized, that is you must allow for it
* there must be clean-out doors to get to the ash
* There needs to be a gap between the outer layer and the core. If the gap it too much you will have poor heat transfer. And if the gap is too small you will have good heat transfer but the expanding core will crack the outer shell.
* some small cracking of the outer shell is common and is nothing to worry about.
* the most stressed area of a masonry heater is right above the firebox. Accounting for extra expansion should be built in here - the mason's often use steel with a firebrick shield. I also saw them stick coins in there (like dimes under the steel lentil). It would have been more cost effective to use pennies, ha ha!

Good Luck