Thank you Brad, appreciate all you do.

I think these aging transformers are a serious potential for danger, I have always treated them with respect and tested them well before power is a applied. But this experience and the way the are manufactured has taught me as has been already mentioned that ev3n if the pass all the intial saftey test a very close visual inspection on how they have come together and where there might be an identifiable failure point need to occur and preventative action taken.
Cheers George

I think these aging transformers are a serious potential for danger

I'd put it more broadly: aging radios are potentially dangerous. They should never be left powered on while unattended. Brad can speak for that having had one catch fire while he was asleep.

The 1930's regulation was fairly specific in that if the transformer faulted, nothing in it could support combustion. Nothing mains, especially going to a display, leaves here without a current tag, if its going to be run.

Give the whole thing a good long soak in marine poly varnish and let it dry for a day or so. This ensures you'll never have to come back to it!

Ian, that is a great suggestion, is "Marine Poly Vanish" better than standard vanish? Is it more moisture resistant?
I have not come across it before, I gather it can be sourced in a Marine Suppy store?

Any suggestions for those transformers where the transformer is encapsulated in wax?

Wax is in various forms, some hard some soft. The hard stuff often cracks & breaks wires. The softer stuff can be melted off. Being a professional bachelor, that is often a simple task with coils, of sitting it on absorbent kitchen paper and slowly winding up the heat.

I have posted a repaired coil where I melted the wax off of it, repaired it and then sealed it with Mar. CRC Urethane Seal Coat. I have actually used the seal coat on cracked wax, where it has not broken the coil wires.

Yes I have melted the wax on RF coils despite the managements dim view, but there is no smell as it only takes less than 100C.
I have considered doing it on mains transformers but didn't think the wax that doesn't run out would be compatible with a varnish. Will reconsider.

I find it unusual to use wax on a power transformer as, should it overheat and be able to catch fire: Then it would not comply with the original regulations. Not that, that seems to matter, or be enforced these days until its too late.

It is astounding as to what gets out there, and has to be recalled, when it should have never got out in the first place.

That's why I used the Mar. It actually formed a seal around the coil. Some wax would have remained, most of the water would be driven out, before it was cocooned by the mar.