Re: Dryer duct toroid?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Christoph Bohr" <cb-at-luebke-lands.de> 

Hello.

Scott is definitely right, don't expand the tube if you can afford it.
I observed this behaviour, too, but for financial reasons always went
the way with expanding the tube to maximum length.... and regretted it soon.
The stiffness really decreases exponentionally with pulling out.
I found that even the tape itself gives the whole thing a lot more stability,
probably by forming something like a comb in the free space between the tape
and the ducting, just like in aviation constructions ;-)

regards

Christoph Bohr

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, November 20, 2004 2:52 AM
Subject: Re: Dryer duct toroid?


 > Original poster: "Bunny Killer" <bunikllr-at-bellsouth-dot-net>
 >
 > Hey All..
 >
 > other than a professionally made spun toroid...  the best I have come up
 > with is the aluminum "dryer" duct/aluminum tape combo but heres the best
 > part... dont expand the dryer duct keep it compressed as much as
 > possible...   yea  I know  it takes 3 X more tubing to make it but its
 > stiffer more dent resistant and after the tape is applied  SMOOTHER...
 > for smaller Dia. toroids...  pizza pans are fantastic for the center
 > support....   large dia. need wood wall panel double coated with aluminum
 > tape ( better stuctural bond)  the last toroid I made was 12" X 52"
 > compressed aluminum ducting and 3 rolls of aluminum tape...   the ridges
 > didnt show up in the tape ( although it took 3 tubes to make it ...ouch 75$
 > worth of tube) but its smooth and alot more dent resistant than expanded
 > tube of the same material ((which would have been 1 tube))... didnt I just
 > say that?  ; )
 >
 > I suppose the 2 most expensive things about coiling are the toroid and the
 > caps.... if you want high quality...  hmmm  okayyy..   variacs are
 > expensive too
 > :)  hell  its all expensive...   GO FOR IT !!!!!  6.7 billion people in
 > this world and only about 1000 of us do T-Coiling    thats only .00067% of
 > the world population
 >