RE>Aluminum foil toroids (f (fwd)

---------- Forwarded message ----------
Date: 07 Jul 1998 11:48:48 -0700
From: Dale Hall <Dale.Hall-at-trw-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: RE>Aluminum foil toroids (f

RE>Aluminum foil toroids (fwd)

Hi Jim,

Where are you located ?   How big is your coil ? 
Here in Redondo Beach, Calif., Home Depot stocks 8'  AL ducting from 3"- 8".
It works fine but dents easily (doesn't look as cool) but functions fine & is light.  
The larger the diameter the less affect of surface imperfections.

Terry Fritz would like the smoothest surface, others don't like AL at the high
arc frequencies (MHz), but in my experience large diameters AL or Galvanized
make up for any lack in smoothness or poorer skin affect conductivity. The
performance difference is "in the noise" unless you are a purest. (I don't recommend AL tape/foils unless you can assure large area electrical contact)

Note AL and Galvanized are relatively inexpensive and commonly available. 
AL dryer ducts go for ~$8 to $17(8") for 8'. Galvanized elbows: ~$16-$45(12") (four), note the prices are not necessarily linear with diameter. (big often=less)
High use diameters are less....and sales abound !!

I recommend you try galvanized furnace ducts. Four 90 degree elbows.
I use 8" and 12 " versions.  Use sheet metal screws for mechanical rigidity.
They are heavier than AL but much tougher. They are available in various thickness' ranging from ~28 (home version) to ~22 (industrial strength & weight)
I like large ones and use breakout points as necessary.

Dale,  Redondo Reach, Calif

Date: 7/6/98 11:54 PM
To: Dale Hall
From: Tesla List

---------- Forwarded message ----------
Date: Mon, 6 Jul 1998 20:04:50 EDT
From: Dsurfr-at-aol-dot-com
To: tesla-at-pupman-dot-com
Subject: Aluminum foil toroids

Help from anybody out there!!
I have checked an even dozen hardware/builder's supply stores in the area &
can't find any dryer duct that is all aluminum foil & wire. All they seem to
offer is solid aluminum (perforated), foil w/ a nylon mesh imbedded in it
(both good choices for dryer duct) or plastic (which I thought was illegal).
My only other thought was to go to the black corrugated drain pipe or a
plastic "slinky" wrapped in plastic strapping tape & then wrapped in Al foil
tape. My one experience w/ this type of toroid ( a small child's toy ring
wrapped in foil tape) seemed to give off a lot of corona loss from the
"overlaps" of the tape. Does anyone have any tips as to the correct wrapping
procedure or any "brand names" of foil ducting on the market?  Thanks, Jim