Re: Advice on Primary

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: FutureT@xxxxxxx 

In a message dated 2/22/05 7:00:52 PM Eastern Standard Time, 
tesla@xxxxxxxxxx writes:

Benjamin,

Whatever you do, don't unroll the tubing in any way except
perhaps to adjust the diameter of the coil.  Keep
it rolled up as purchased for all steps of the project.  Using
notches is 100 times easier than using holes in the supports.
I've done it both ways.  In the case of holes, you have to
think of the coil of tubing as a screw, it screws though the
supports.  THink of the spiral binder on a notebook.  You
can unscrew it from the pages by rotating the spiral.  You
can re-install it by screwing it the other way.  Using notches,
you simply hold the entire roll then wobble it a little so a
turn of tubing catches each support in turn.  It goes super-fast
and is super-easy if done the correct way.  It's always hard
to describe the technique using words.

I'm not sure what double-wound means.  Two lengths wound
together?  Or wound one way then a sharp bend in the center
then wound the opposite way?   If the first is true, then it may
be possible to tease apart the two coils.  In the second case
it may be possible to straighten the sharp bend and create a
coil of all one direction, or cut it there and splice.

If this is a dished pancake coil with notches, the easiest way
is to mount the supports to the plywood first.  Next simply
hold the entire spool over the supports, and gradually move
the entire spool of copper tubing over the supports and catch
each one in turn.  This is easy to do.  You may need to change
the curve of the coil slightly as you do this if the coil as purchased
is either larger or smaller than the final diameter needed.  But
don't attempt to straighten the coil and re coil it.  THis would
result in a giant nightmare.  Some folks drill a small hole below
each notch (for pancake coil), then they place a nylon tie-wrap
through the hole and around the copper to hold the copper at
each notch.

Yes, you can splice by placing a thinner brass or copper rod
inside and soldering.  I sometimes use a thin coupler on the
outside of the tubing.  The splice won't hurt the performance.

Have fun,
John