I hope this isn't redundant, but it's so good (I think, anyways) that I thought it would be worth it. I was reading another forum recently, and there was a post there referring to a website containing a whole bunch of .pdf files on how to make all sorts of labware. There are books there on making stuff for chemistry, physics and biology labs. It's pretty cool.
http://icase.unl.edu/i_on-line_pubs.htm (http://icase.unl.edu/i_on-line_pubs.htm)
thanx every bit helps
check out the gas generator
http://icase.unl.edu/guidboks/chemistry/chemgas.pdf (http://icase.unl.edu/guidboks/chemistry/chemgas.pdf)