[R-390] Filters

[Charles P. Steinmetz]

John wrote:

>Not sure how to repair that problem - maybe some sort of arc welder with
>a car battery and some way to interrupt the current before the steel 
>wire melts.

I think you'd grasp the wire firmly very near the end with hemostats 
or similar, then attach one lead of your spot welder to the disk and 
the other to the hemostats.  Touch the short end of the wire to the 
correct spot on the disk, and trigger the spot welder (making sure 
the hemostats are not touching the disk, and that you are holding the 
hemostats with a good insulator).

Do you know any orthodontists who might collect old orthodontic 
equipment (or at least not throw it away)?  The sort of welder I'm 
talking about was used to weld stainless steel strips into 
orthodontic bands in the bad old days.

You could try jury-rigging a capacitor discharge in lieu of the 
welder, but you'd have to be lucky to get it right.

For those who haven't seen it, John has a lot of good information 
about mechanical filters on his web site:

http://jlkolb.cts.com/

Best regards,

Charles