I relate to Goldilocks in that classic children’s story. I don’t like being too hot or too cold; I like it juuuust right.
But lately I’ve found myself trying to be too hot. I’ve been trying to bring up to temperature the sauna my family and I built, and it is far more difficult than I expected.
First, I built a rocket stove, totally out of brick. If you aren’t familiar with a rocket stove, it is a wood-burning stove designed to burn very efficiently. I built the type called a J tube style — composed of a vertical feed tube, a horizontal burn tunnel, a vertical heat riser, a bell which sits over the heat riser and of course an exit and chimney.
I chose a 6-inch system, which ought to be capable of heating a small home with a few hours of burn in the morning and evening — at least according to the book and websites I read. I thought it would be ample for heating a single eight foot by eight foot room.
It did heat the room — but not to the 150-degree minimum for a sauna. I would like to raise the temperature above 200 degrees, as I’ve read that those are traditional temperatures for a wet sauna (that is, one with a lot of steam).
I used building materials I had on hand; bricks (left over from other projects) and mortar made with water, sand, and clay I dug from a nearby pile of recently turned soil.
The mortar was a little tricky to make because the sand I had was wet, which made for a sloppy situation.
But I worked through that, and built the stove.
I followed the dimensions given in a book about rocket stoves. I read that the correct proportions of the elements is crucial to achieving a good draft in the stove.
Let me tell you, the draft was good. The first time I lit the stove I put a piece of newspaper in to get it started — I put a match to the paper, and as soon as it caught the whole piece of paper was sucked right into the burn tunnel and up into the heat riser, never to be seen again.
The draft worked so well in fact, that I learned to cover the top opening of the feed tube with loose bricks as I was getting it started. The draw was so strong it created a wind through the feed tube which extinguished the flames before they could get established.
However, the mass of the brick bell was too great, and thus took too long to heat for my situation. So I dismantled the outer bricks and replaced them with a metal barrel (leaving the rest of the build intact), which is a common feature of rocket stoves.
The barrel heated almost instantly. But after a six plus hours of burning the room capped out around 80 degrees. So we tightened the building, blocking air gaps. Then we burned again for over six hours, and the temperature capped out at 100.F So we tightened more air gaps.
It is a cool system (pun intended) — the strong draw pulling the flames horizontally keeps the room from being at all smoky.
I enjoy tending it, although I hope to reduce the time it takes to heat the room down to just a few hours. I also enjoy having built it myself, for almost no cost.
ALDONA BIRD is a journalist, exploring possibilities of local productivity and sustainable living in Preston County.
