What do you use as a sealer for rigging thread?

[Mikeyt]

I've used Bees Wax on my cotton threads lasted 35 yrs so far no sag or stretch so far works great so far and it's not expensive and it's compact

I then tie regular knots and sinch them tite and a small drop of wood glue off the point of a bobkin

 

[Neil_jo]

Well I bought some Zinsser bulls eye clear shellac and it seems to work fine.
It doesn't discolour the line or make the brittle like C.A. glue does.