Knot Bleed Through

[Starchy]

Last summer I screened in my front veranda, 8' x32'. The portion under the large screened 'windows" is about 18" high, made from tongue & groove pine from a box store. I applied 3 coats of white shellac to the knots before applying 3 coats of solid white oil based stain. Later in the summer, I noticed that some knots were showing through the stain, so I applied 2 more coats of shellac and 2 more coats of stain. I have now noticed that just about all of the knots are showing through again, more on the inside of this "wall" than the outside. The porch faces east, and these wall sections don't really get very much direct sun. Is there something I missed during construction? More importantly, what can I do now to permanently cover the knots so they don't bleed through again?
Thanks for all replies.

[HayZee518]

the resin in the knot will always bleed through until the knots thoroughly dry out. zissner kilz may coat the knots

[Starchy]

Thanks HayZee518. If I apply a brand name over the stained knots as you suggested, will that stop or slow down the bleed through? Or do I have to sand off to bare wood and start again? I hope not.
Thanks again.

[HayZee518]

the zissner's kilz is also alcohol based but its a heavier primer

[Starchy]

Thanks Hayzee518. I will look for that shellac. Do I have to sand to bare wood or can I apply it over the surface that has been shellaced and stained numerous coats?
Thanks again.

[HayZee518]

I think you can get away with just scuffing the surface with 000 steel wool. the "kilz" is alcohol based so successive coats will soften the previous coat ever so slightly and "bite" into it.

[Starchy]

Thanks again, I shall buy a can of the Kilz and try it. If I understand, I can apply it after scuffing the surface with steel wool or maybe 220 sandpaper. This product will do some good even if it is applied over the stain that is on the wood now?

[pushkins]

Use the Gold Zinsser as Hayzee mentioned it's shellac based, you won't need to sand any previous surface, (you also won't be able to stay in the room very long till it's dried)