Wax is certainly possible but I have to wonder if the wax would need new
applications less frequently on a hard poly surface rather then a bare wood
surface. Of course the nice thing about the thought is that one can try just
the wax and if it doesn't work out move on to something else. It's a lot
easier then backing away from a cured poly surface.
Shellac on a router table top? Maybe, if it is kept well waxed. Lets face
it, as much as I like shellac, it isn't the best finish to resist abrasion
scratches and a router table top does, by it's nature, have firmly held down
wood, sliding across it as a matter of course.
About anything smooth that gets between the wood to wood contact would work
it's just a matter of weighing the amount of upkeep the surface chosen will
require considering the use the top will get. Another possibility would be
smooth stick on floor tiles. Cheap and easily replaceable if they get dinged
Myself, if I ever get around to building another router table, the top is
going to be Formica. It's hard, slick, and as a counter top material fairly
resistant to scratching. And yes, it will be kept waxed.
Of course one has to remember to allow for the thickness of whatever you use
when setting up the hole for the router and inserts..
Hope it helps.
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