I had a mishap this week when the main terminal on a tractor starter
motor became loose and rotated allowing it to contact the motor winding
terminal, while the engine was running. I didn't notice anything until
the damage was done.

As this is an old ford industrial engine the starter is going to take a
while to arrive so I thought I'd see if the old one could be made
functional again.

The armature seems okay, no shorts to the iron core and the commutator
and brushes are serviceable.

One of the 4 stator coils has shorted and burned off its wrappings, the
others seem fine, the copper is so large a cross section it is not
possible to discriminate the resistance as it is so low but the copper
rectangular section looks sound.

Now looking on you tube if anyone has the time to watch some old school
workmanship:

https://www.youtube.com/watch?v=4bFou5VIFzM

at 2 minutes the guy is cutting some insulation sheet, anyone any idea
what it is and if it is avalable?

Later at 4:20 he wraps with a tape, any ideas what it is and where I can
get some?

At 5:40 a paint is used to cover the wrapped coil, is this likely to be
anything special?