On Tue, 24 Apr 2012 11:55:25 -0400, "Flying Pig"
wrote:

If you've been paying attention, you know I've dropped my rudder and have
been removing prior attempts to epoxy pits in the shaft - done in a
convoluted, upside-down manner, inside the boat - which turned out badly.
With the rudder out, I have access to it conveniently, to do it up right
(well, as best as possible in that it can't be sent off for grinding,
rewelding, and machining to round again).

I believe I have all the prior epoxy out. Some of the pits have tunnels up
or down, too, which, as I worked them out with the pick, displayed remnants
of prior packing material. Not so good. The good news is that nearly
everywhere I managed to pick off shows very bright under the old epoxy, so
it's clean (or will be when I use a brush and acetone to remove all solubles
which may be hiding on the surface, and which would impede bonding).

The area covered by the packing gland has minimal reduction in diameter -
mostly 2-5, and at worst, ~8 thousandths of an inch (out of 2"). However,
I'd like not to have even that, if I can avoid it...

===

Well everyone else has had a shot at this so I'll dip my oar in the
water also. Rick is on the right track with his mold approach but
I'd do it differently. I'd buy a sheet of heavy duty mylar which is
available at any art supply store or sailmaker. Next I'd coat one
side of the mylar with wax or mold release. After filling the pits
with Devcon/epoxy/Colloidal Silica or whatever, I'd wrap the shaft
tightly with the mylar (wax side down of course) and try to squeeze
out any excess epoxy as I wrapped. Leave the mylar on until cured by
wrapping it with masking tape or some such. If done properly, this
will minimize the high spots and the amount of sanding to be done.

The sanding should be done with long strips of emery cloth or wet and
dry sandpaper, using them like a shoe shine cloth wrapped around the
shaft at about 180 degrees. Change the angle frequently to avoid
making an oval shape. I have successfully dressed the shafts on
anchor windlasses in this way after they've become dinged/distorted.