Etching your own flex connector? Source of flex "PC board"?

[Bruce Freeman]

I see a lot of good references here for etching PC boards. I have a
related problem.

I need to make a replacement part for an obsolete printer. Namely, a
flex cable to the print head. I don't know the proper name for the
material this is made from. It's like PC board, but thin and
flexible. The flex cable appears to have been made like a PC board -
by etching. (Copper is all on one side.)

I could make a replacement by some other means, but the terminals
would be difficult to reproduce by any other means, especially because
the thickness matters.

Does anyone know a source of fully-copper-clad flexible material that
could be etched to make a cable like this?

Thanks,

Bruce Freeman