This is a fascinating set of videos showing the operation of a gasifier made largely of clay (plumbing is still performed with steel tubes) and scrap to produce gas for a 10kW generator.
Many people are put off by the thought of having to employ welding to build a gasifier. The idea of building a fully functioning downdraught gasifier without recourse to welding, and still being able to produce gas good enough for a generator, will hopefully get more people interested in building their own generator.
Build your own simple MIDGE gasifier (plans on the right-hand side) and see how simple it is to gasify wood. After you have understood the principles of gasification, and see how it applies to downdraught gasification, then it does not matter how you build a gasifier.
The camera work is not too steady but what there is to see is more than inspiring.
Video 1 - Overview of the generator in operation
Video 2 - Close-up of various aspects of the producer
Video 3 - A clearer look of the producer made from clay. One suspects that there are significant metal components inside the producer but sealing the outside with clay means there is no need for welding.