The amount of heat flow into that sliver of metal will be tiny, so any
adhesive will work the same. The thermal resistance of the metal to
the air will dwarf the thermal resistance of any adhesive. I suspect
the function of the metal may not be thermal anyhow.

Besides, filled adhesives aren't all that much better than unfilled
ones, even if the filler is diamond.

That bad?

Run it for 30 minutes, as-is, and see if the transformer gets hot.

John

I was thinking to put just a thin layer of silicon heat sink compound on the
top of the transformer (on top of the copper strip) and refit the chunk that
is stuck to the heat sink. That way, if the original adhesive *is* thermally
conductive, I'd restore most of its original function.

Thanks.