According to Christopher Tidy :

[ ... ]

laminations a wipe with white spirit before I reassemble.

That will probably do well enough.
Before that I
need to build some kind of jig so that I can wind neat coils. It didn't
occur to me at first that using thick (2.5 mm) wire would make winding
more difficult, but it looks like I need to avoid twisting the wire as
it is transferred from the reel to the transformer bobbin. I'll post
some pictures when it's done (probably a week or two).

Hmm ... I've seen transformers with heavy wire (around this
size) wound with *square* wire -- to maximize the conductor's
cross-sectional area. Otherwise, there are air gaps between wires which
are just waste space.

Obviously, this would require even more care in the winding,
assuming that you can find the square wire in the first place.

Older transformers that I've disassembled have had a very thin
waxed insulating paper between layers of the wire -- to keep the wire
from bunching up, and especially to minimize the voltage between closely
adjacent wires, which could otherwise be a problem if an upper layer
dropped into a much deeper layer.

obviously, if you are going to be using 2.5mm wire, round or
square, you won't be developing enough voltage to have to worry about
this unless the transformer is a *lot* larger than I have been thinking. :-)

Good Luck,
DoN.
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