I googled and all the DIY recipes say to mix sanding dust
with wood glue. I'm thinking of mixing Penofin deck oil with
sanding dust. Has anybody tried this? Or linseed oil or
anything similar?

The cedar railing on my deck has cracks and checks which I
want to fill before giving it the semi-annual oiling. I'm reluctant
to use glue as here in Oregon the railing will be WET, not damp,
for 6 months per year and I just don't trust wood glue. Even
TB3 in those conditions. Epoxy is out as it won't take the oil and
will look ugly.

Any words of wisdom appreciated.
Art