At 08:55 PM 10/26/2005, Gary Schafer wrote:
>Using a straight tube for a chimney does not direct enough air around the
>top seal of the tube.
>
>73
>Gary K4FMX
The pickle jar is not a straight chimney. And there is no need to cut
off the threaded part. In fact that is the tough cut since the glass has
irregular thickness at that point. It curves in to the screw-on top with
about the same hole diameter as an Eimac chimney, directly a good
flow of air and the plate cap.
Just cut off the bottom at the right spot by mounting a glass cutter in
a vise at the proper height and rotate the pickle jar around the table.
You might be able to TAP it off, but I always use a nichrome wire
in the cutter track and it will "plink" off very easily with a little current.
I have known people who have used these one gallon jars for years
on both 4-1000s and 3-1000s with no problems, but I suggest good
airflow helps keep them cool as well.
--John W0UN
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