secondary coil form materials

["John Morawa" <morawaj-at-interaccess-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hello everyone,

Can anyone recommend a material for secondaries coils?  Something that can
be found in a 4"-6" diameter.  Normally I use PVC but I understand that it's
RF qualities are not that great.  Of the two which would be better, acrylic
or polyethylene?  Or is there something that is similar in $ but better for
secondaries?  Also, for a coil of that diameter, what is the minimum wall
thickness to keep it rigid enough to wind.  Is 3/16" ok or is that too thin
or thick?

Thanks for any comments,
John M.