[Lowfer] Repairing Ferrites

[C. Turner]

I've used Super Glue to fix ferrites several times.  Curious, I actually 
broke a toroid once and did a before/after measurement and couldn't tell 
a real difference - but since it was hard to get the turns back exactly 
where they were in each case there was a bit of (expected) variation.

I've also been known to extract the cores from flyback transformers from 
dead TV/monitors to use as chokes for coax/USB/ethernet cables (that's 
about the only thing that will work at LF!) and when I've broken them 
during the extraction process, I've just super-glued them back together.

Many years ago (perhaps 25) I lost a transistor in the finals of my TR-7 
due to a parasitic oscillation in a driver and in the processes, the 
cores in the output transformer shattered from thermal shock.  Being 
cheap, I simply super-glued them back together and then put epoxy over 
the joints on the outside - just to be on the safe side.  They are still 
that way and - since I long ago fixed the parasitic problem - the radio 
has continued to work fine on all bands 160-10 meters.

The bad part about super glue is that it can't tolerate really high 
temperatures and it will lose its bond in the continual presence of 
moisture, hence the reason for putting that bit of extra epoxy on the 
TR-7 cores.  Since ferrite usually tends to break fairly cleanly, it's 
probably unlikely that moisture would actually get into the bond except 
under extremely wet conditions.

73,

Clint
KA7OEI/CT