DIY Low-Cost Plywood Hot Tub

DIY hot tub, based on sheets of 6 sheets of 3/4" plywood and 2x4 studs. total cost 1600USD. minimum 2-week build time, still a work in progress at this stage. should cost only $0.20/day to run in the winter.

updates:
Upgraded: DIY low-cost hot tub,