RE: Advice on Primary

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Ralph Zekelman" <gridleak@xxxxxxxxxxxxxx>

Ben,
Do not unwind the coil of tubing and don't try to feed it thru the
holes. Notches are fine. It sounds like you have gotten into hard-copper

refrigeration tubing which is NG for coil winding. You want the soft-
copper tubing as used for house plumbing. I have used 1/4  inch
tubing and it's probably OK at lower power levels like maybe the
2.25 kW that I run, but it does get a little warm. I'll use 3/8 if I
ever
boost the power. Looking at the photo, I would cut notches just
wide enuff for a slight force fit of the tubing down into the holes.
Start from the inside and unwind the coil as you work your way
to the outside turn. No problem in splicing the tubing. Two good
ways to do this: You can sweat solder a piece of  the next size
larger tubing over the two ends, or, you can sweat solder a piece
of solid copper wire inside the two ends. Somewhere I have the
equation for determining the length of tubing needed but it is
faster to just splice the ends if needed.

Much of the fun is in the learning. Don't be afraid to make miztrakes.
Good luck on you project.

Ralph

Original poster: "Medina, Benjamin (UMR-Student)" <bamxbb@xxxxxxx>

Hello,

I know this topic has already been discussed but I am still having
doubts
when it comes to the winding of the copper tubing through the holes or
notches of the supports. So if someone could clear this up for me that
would be very much appreciated.

As of now this is what I plan on using:

1. A 50ft roll of 1/4" OD refrigeration copper tubing.
2. A 3/4" thick sheet of plywood as the base.
3. 5 supports in an L shape cut out from a cutting board I got at
WAL-MART
fixed to the plywood base with screws (similar to the image below).


http://hot-streamer.com/temp/Medinaimage001.jpg


At first I thought of fixing the supports to the base and winding the
tubing through the holes, but now I am realizing it will be a PAIN!!
Therefore, should I slide in the supports, starting at the center and
work
my way outside, through the entire roll of tubing? Or should I start at
the
ends and work my way inside?

Some people prefer holes in the supports; others prefer notches. I am
not
sure about this. I am thinking that the notches might bend the tubing if

one is not careful when doing this. Any suggestions?

Say I want 15 turns. While winding the tubing, let's say I run out of
tubing on the 11th turn. Is it okay to solder another continuous piece
of
tubing to the original, to complete the 15 turns or not? I guess, what I
am
asking is if I need a continuous roll of tubing or not? Will this affect

the coupling and/or the overall performance of the TC?

Another thing I noticed is the fact that the tubing is double wounded,
making it even more tedious to work with it. A guy at Home Depot
suggested
to unroll the tubing on the floor and then wind it on/through the
supports.
Any suggestions?

I appreciate your time. Thanks for the help.

Regards,

Benjamin Medina
Rolla, Missouri.