Daniele Fua wrote:

Thanks to you all, the poll had one unanimous response and I will comply
for su epoxy.
Thanks to Steve for the additional advices: I will follow them too.
My planks are already 1 inch thick which puts me on the safe side and I
will cross the grain directions. I was also thinking of gluing teak
veneer (approx 3/32" thick) on the sides in order to protect the open
end of the fibers.
Daniel

Or maybe a couple of layers of 1/2 ounce "deck" cloth and epoxy to seal
everything?