Same as above: Secondary used for spot-welding.

The demonstration transformer shown in D+75+0 can be used to demonstrate spot-welding. The secondary has been replaced with a low resistance coil of 5 turns (made of bent .8 mm thick copper rod). When the secondary is shorted, several 100 amps can flow. Two nails can be inserted and secured in the welding section. When the handle is squeezed, the nails make contact and glow white hot, and will ultimately fuse. Also, several pieces of thin metal can be overlapped and placed between the welding points. When the handle is squeezed, the metal piece can be welded together. Note that there is an insulating sheath separating the secondary coils from the iron core of the transformer. Also, the handles are wood, to minimize shock hazard.