Re: The Magneon Porkchop
> Nice job on the primary! What did you use to bend the copper?
> What are the supports made of ? How are winding attached?
> Jim McVey
The backbone structure of the primary is made from beach wood, which is
painted light blue. This supports the strikerail, which is glued to the
wood with epoxy. On the top faces of the supporting spokes, is routed a
groove 6 mm / 1/4 " wide and deep. Into these groves, the acrylic
"combs" "are inserted, and glued, I used chemical metal for this, since
it sets in 10 minutes, and I wanted to get the tubing in the same day.
To bend the copper into a spiral, I first made a piece of wood into a
male image of the hole in the middle: Spiralling out 16 mm in one turn.
I secured this inner plug to a piece of plywood, as big as the primary
OD, the bottom plate, in fact. Placing the start of the tube at the
smallest diametre, and knocking a nail down next to it to keep it
secure, I could now bend the first turn.
For the following turns, I incerted narrow strips of linoleum (used to
cover floors, bendable and only 4 mm thich: 2 of them needed ) to take
up the spacing btwn turns, and then it is a relatively simple matter to
turn a bit, incert more spacing, turn some more etc... . The result is a
clean looking primary, that almost drops into place, when lifted over to
It is a minor matter to arrange the spirel into the 1/2 holes in the
combs, and I tie the tube down with short pieces of copper wire as i go,
perhaps tying the tube down to each 3rd spoke.
When everything is in place and checked for allignment, I start from the
outside of the spiral and drip a sufficiently small amount (to avoid
that it runs down the acryllic, and fouls the surface) of cyanoacryllic
glue into the 1/2 hole under the pipe, lifting it as needed, and
pressing the tube down perhaps 10 seconds afterwards, to insure proper
curing of the glue.
This way the various components of the primary bond together to form a
rigid structure that still has a light "airy" touch to it.
If you need further clarification, don`t hessitate to ask!