Hi George

Yes that works real well also, I don't have a burr mill, and use the end
of a stanley knife blade on a dremel arbor, load some small chunks in a
glass jar end shake the dremel/jar combo until I have enough small, fine
and coarse pieces, I think your burr mill would do a nicer job but this
works also.
As the question was about the coffee ground, I didn't include this way
of improving things, and yes I think in some cases this (bark) does a
much nicer job.

Have fun and take care
Leo Van Der Loo

George wrote:

My earlier didn't make it through my ISP, but putting some bark through a
burr mill makes a great filler that looks absolutely natural in a bark
pocket. You can grind coarse or fine, and filling below the line and
sprinkling the rest on top of accelerated CA gives you something that takes
a finish almost like the real stuff. With epoxy or CA solid, you have to
"tooth" it to get a varnish to stick and equalize the appearance.

Big cracks are stuffed with bigger unground chunks, and look pretty good as
well.