Question:
Has anyone here have any experience building an inground wood-heated hot
tub.
Answer:
You don't need antifreeze. nothing complicated about it.
Bend copper tubing so one end is at the bottom of the pond, it comes up over
the rim and forms a coil over the fire, and returns to the rim and ends about
six inches under the water surface. One-piece-construction. - simple.
The heated water will create flow, by thermodynamics. While the refractory mix is still wet, fill the
card board tube full of wood scraps and paper, and light. Let it burn
down about half way, sit the lid on, and turn on the blower. Before
the fire goes out, turn off the blower, fill it up with wood again,
and replace the lid. Turn on the blower, and let that burn down. Now
fill it half full of charcoal and let burn down, turn off the blower
an let the drum set over night. Now plumb the copper tube at the top
of the drum into the bottom of your hot tub, and the copper tube at
the bottom of the drum into the top of your hot tub, at the opposite
side of the tub. Place about 6 to 10 2x4 blocks ( the drum should be
less than half full) and light the blocks. When the fire is going
good, put the lid on and turn on the blower.
Then get into the hot tub and relax !
