Make a rocket powered hot tub - plumbing.straw.rockettub PEP BB

This is a badge bit (BB) that is part of the PEP curriculum.  Completing this BB is part of getting the straw badge in Plumbing.

In this Badge Bit, you will make a hot tub powered by a rocket!  Not a NASA type of rocket, a j-style one that runs on twigs.

Elements of this will certainly qualify for a Rocket bb.

To complete this BB, the minimum requirements are:
  - heat a tub with a j-style rocket heater
  - homemade
  - big enough for two people who aren't romantically affiliated
  - heats the water to 105F in under an hour
  - unpressurized so if it boils there isn't a boom
     - no coil of copper pipe in the heat zone

To show you've completed this Badge Bit, provide proof of the following as pics or video (less than two minutes):
  - some of the parts you're building it from
  - plumbing underway
  - finished rocket heater
  - evidence that it can't explode if it boils
  - evidence of heating water from under 60F to 105F in under an hour (or 70F to 105F in 45 min) (or 80F to 105F in 30 min)