we deal with this all the time. there are two solutions: 1 is to change
the surface energy of the epoxy by adding a fisheye preventer, or
wetting agent, which you can get from an automotive paint store. 2, is
to add cabosil (colloidal silica) , to thicken the epoxy until it
wont bead up. it often makes sense to put on an unthickened coat (which
will seep into cracks much better) and then follow immediately with a
thickened coat, which will not bead up. good luck. Dick Pereli