blueman wrote:
Our 140yr old Italianate house has beautiful wooden quoins forming the
corners of the house. Each side of the corner looks like a series of
blocks with raised panel centers.

Unfortunately, many of the quoins now have horizontal cracks in the
wood up to 1/8" or so wide. I would like to repair rather than replace
them since matching the detail and quality of wood would be very
expensive.

I could obviously just have a field day with caulk, but I was
wondering whether there was a better way of restoring the wood. I
considered using a wood epoxy but wondered whether the gaps are too
narrow and how it will behave under seasonal contraction/expansion.

So any suggestions on how to patch up these cracks?

Epoxy would work as would Bondo. If you keep up on the maintenance and
make sure the quoins are painted and caulked where necessary that will
keep the contraction and expansion to a minimum, and you won't have to
worry about the epoxy or Bondo falling out.

And thanks for using the correct spelling of quoins!

R