> "" <[EMAIL PROTECTED]> wrote: > I have built cans in the past and would NEVER do it again. It > is a waste of time.
Some people don't have great results... > As the metals expand and contract, so does the tuning. The > main tuning rod shafts are the biggest problem. The metal > needs to have ZERO coefficient of expansion properties. Unless > you have access to such material, DON'T GO THERE! I went there with pretty good results... if you build the plungers right you don't have a big problem with drift once they're locked down. Telewave's plungers are just copper pipe with quality fingerstock. You don't have to use metal threaded rod... > I had to tune the cavities I made around 7 times a day in > a relatively stable but not totally stable temperature > atmosphere. Something you did in your project was not as well done as it probably could have been. > Yes, it is a very good learning experience so you can > appreciate how good a commercial set really are. Probably true in your example. > The can changes can be minimized by making use of a VERY LARGE > diameter can, such as a metal garbage can, so its change has > little effect on the center section. Not the way to go about things... more like material thickness and rigidity are the big players in the game you mention above. These stove pipe cavities I have here include steel angle iron bracing on the cavity hot end. Decades of stable operation so far... > ZERO coefficient of expansion metal is vital. I can assure > you, you will never be happy with a home made duplexer. opps... now I've got to go pull the 5 or 6 home brew duplexers we use out of service. cheers, s.
