Homemade hydro excavator?
Then it occurred to me:
A standard pressure washer could be used as part of homemade hydro excavator -- a digging tool that liquefies soil and removes it with a vacuum. These machines can excavate around pipes without damage and make surgical-style incisions in the earth. Very precise. Very fast. Factory made hydro excavators are *very* expensive and they typically rent for $350.00+ per day.
To turn a pressure washer into a hydro excavator, you'd need an economical homebuilt vacuum tank to suck up the liquefied soil and a vacuum hose attachment for the wand. The excavated liquefied soil is very heavy -- so weight considerations and spoil removal are engineering issues to work on.
So ..... anyone know how to build an economical vacuum tank?