Can I apply knotting solution to bare wood once it has been primed?

Yes it probably would, lightly abrade the primer first before applying knotting, although to save and time hassle you might want to consider using a white knotting like Zinzer or Classidur. You might also want to consider using an undercoat in order to build up the surface as a good foundation for your finish coat of satinwood instead of going straight over primer, or else apply a couple of full coats of satinwood. If you are painting handrails eggshell would be a better choice as it is more hard wearing than satinwood although the finish is pretty much the same. Hope this helps

Hi, No you are defeating the object if you do. Get some 80 grade sandpaper and just take it off the knots it shouldn't take long. Then knot and spot prime. I noticed you are putting Satinwood on, I know it's self undercoating and you can put 1 coat on, but I always recommend 2 coats as the 2nd coat just gives it that little extra. Hope this helps Tom