transformer power/weight ratio

[george a]

Hi All

Does anybody know of a "rule of Thumb" for estimating the VA rating of transformers (non toroid) based on weight, I seem to recall having read of some issue like this somewhere.
I Have some old trafo's I bought some 20 years ago in a surplus shop, they were advertised as being 50 V ct 50A but having seen some photos of some others on the net , I suspect they may not be so.
Wire on secondaries is substantial guage also.

I will need to weight them but of the top of my head they are rather heavy though not massively huge
Thanks in advance

[Stocker]

The more scientific sounding rule of thumb is cross-sectional area of the the core. There is a chart out there...somewhere.