Could I superglue a knot in a brush? With a water resistant glue? The knot will be 1 mm smaller than the hole so it's not a problem if the glue swells a little...
OK, so epoxy glue it is... The one in syringes.
Now one question about epoxy glue. As I drilled the previous knot, the bottom is uneven. Could I fill the hole to the depth I want with epoxy, let it rest so it's perfectly flat (by means or gravity filling all the gaps) and than, when its dried, glue a knot (again with epoxy) on the existing epoxy filled hole?