They are very easy to construct.  The most time consuming part was picking 
out all the parts from the hardware store so that everything fit together 
properly.  All together, including shopping time, it took me only about five 
hours to build my first one.  After that, it gets much faster.  So, it's 
really easy to construct.  I encourage everyone on this list to build one for 
experimentation.  You can even put one on your car.  Paul, the inventor, has 
one on his 1985 Chevy Suburban.  He's getting great mileage and near zero 
emissions using 1/2 gas and 1/2 water.  You can check out the details on this 
at their Web site:  www.geet.com and follow the links.  
Warm regards,
Peter