I made a nice isolation transformer from a micrewave oven one.. But it required quite a lot of work.
- need to disassemble the existing transformer (cutting welded joints with dremel, separating plates, removing magnetic shunt etc)
- need to remove all windings. They are made of copper cladded _aluminium_ and have no use. Primary also has too few turns, microvawe oven transformers are designed to work in saturation when not loaded
- need to make a coil bobbin
- make first winding with a proper copper wire (about 1 turn per volt)
- make screen between windings
- make second winding
- make this bloody thing not humming by soacking windings with hot epoxy
- glue and bind iron core together..