[AMRadio] Type of glue to use

[Donald Chester]

>
>I have a B&W 850 tank coil that needs repair. There were some plastic
>(?) strips glued to the coil spacers to support the whole coil. The glue
If you are using plexiglas strips, its best to use acryllic (or is it 
acrylic) glue or plexiglas cement.  Plexiglas is a trade name for acryllic.  
The glue is a solvent with the plastic mixed in, to a consistency of model 
airplane glue.  It dissolves the plexiglas and when it hardens,  it actually 
welds the plexiglas, forming one solid piece.

I have also used 2-ton crystal clear epoxy to fix coils.  It doesn't adhere 
to plexiglas as solidly as the cement, but I never have had one fall apart 
on me.  Actually, the coild don't use plexiglas, because it is only a fair 
rf dielectric at best.  Polystyrene (Victron) is commonly used, and has much 
better rf characteristics.  If you can find polystyrene cement for minor 
repairs to the original plastic, use it.  Epoxy  seems to  have excellent rf 
dielectric characteristics.  If you could fabricate some kind of mould to  
hold it, you could pour new insulator material out of epoxy and have an 
excellent support, both mechanically and electrically.  I recall an article 
to that effect in a recent issue of QST, but don't recall which one.

Don K4KYV


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