[AMRadio] FT102 and HDVL for 160


Mike Sawyer w3slk at uplink.net
Sun Oct 9 20:12:48 EDT 2005


I did this with a B&W 850A. I took some clear acrylic and dissolved it in 
acetone. I then applied the 'glue'. It turned out pretty good but I have yet 
to install it in a rig. It did wind up with some small bubbles so I would 
cut back on the solvent next time since I think they were created by to 
quick evaporation. I tried ethyl di-chloride once but made the acrylic 
almost rubbery and wouldn't set. I would have to say the ideal way to do it 
would be to use a dc power source with a current limiter. Put the pieces of 
acrylic/Plexiglas® and clamp each support. Let the coil get just warm enough 
to form into the acrylic with the ability to 'mash' the top to keep it from 
de-forming.
Your mileage may vary.
Mike(y)
W3SLK
----- Original Message ----- 
From: "Donald Chester" <k4kyv at hotmail.com>
To: <amradio at mailman.qth.net>
Sent: Sunday, October 09, 2005 7:32 PM
Subject: Re: [AMRadio] FT102 and HDVL for 160




>What's the name of the epoxy that dries as clear as glass?  I imagine if it
>was applied properly, it could be made to look a lot like the bars that are
>use in B&W Coil-stock.

There is a brand called two-ton crystal clear epoxy.  As far as I can tell,
it is a very good rf dielectric.  I have used it many times to repair these
coils.  I have also used it to glue plexiglas; it works fairly well, but the
best solution for plexiglas is acrylic cement.  Plexiglas is brand name for
arcylic.  The glue looks like model airplane glue, but it is basically
plexiglas mixed with a solvent.  You can even buy liquid solvent for
plexiglas, grind up some of the plastic, mix in the solvent, and make your
own "glue."  The principle of operation is that the glue "welds" the two
pieces together by dissolving some of the plastic on the pieces to be glued,
and fusing with the glue.  When the solvent evaporates, the result is one
solid piece of acrylic.  It is very effective for sandwiching the wire of
the coil between two strips.

A couple of years ago I read an article in QST about homebrew air core
coils.  The author rigged up a mould for pouring crystal clear epoxy so that
when it  hardened it formed insulating strips just like those in the HD
series coils.  Epoxy insulated coils shoud last for ever.

Don k4kyv


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