I painted some knotty pine doors about 3 years ago but (despite applying knotting solution) knots are showing through on nearly all of them!

I followed the instructions on the bottle of the knotting solution (applying 2 / 3 coats with a rag IIRC) but obviously

  • a) I did something wrong or
  • b) the knotting solution I used (which was basically shellac) or
  • c) these doors are really knotty

Any suggestions as to why I have such a paint failure are welcome but what I would really like to ask is... is there a product on the market that will

  • paint over gloss paint
  • and will definitely seal the knots

I do not like the idea of sanding the doors (I have nine) back to the wood and I do not want to have to repaint them every 2 - 3 years.

Follow up

I have done a bit of googling and found this post. It sounds like this Zinnser 123 or "ZinBin" are products similar to the "Kilz" paints mentioned by DA01.

I shall get one or the other (probably Zin123 since that is a bit cheaper and is soap+water cleanable (something I always like) unless anyone knows that ZinBin does a better job that is.

  • after applying the knot sealer solution did you then paint the doors with wood primer (1 coat), undercoat (1 coat), then finally gloss (normally 2 coats)?
    – Mike Perry
    Jul 3, 2011 at 18:49
  • I didn't do an undercoat - just white primer then 2 coats of gloss. Would the absence of an undercoat affect whether or not the stain came through? Jul 3, 2011 at 21:32
  • honest answer I don't know. When painting new wood I have always used the procedure I outlined in my initial comment (plus used a knotting solution prior to painting) and have never experienced the problem you are currently experiencing (touch-wood)...
    – Mike Perry
    Jul 3, 2011 at 22:31

1 Answer 1


Knotty pine is great if you like the look of knotty pine. It sucks for every other use.

Otherwise, look into the line of Kilz products. They may have one that will do the job for you.

  • I agree about knotty pine. In hindsight I should have gone for the cheap (hollow) internal doors. They even come ready primed. As well as showing stains, some of the doors have warped since hanging (a problem that I have since learnt is not uncommon with cheap pine doors). Thanks for the tip about Kilz - I live in the UK and it looks as though these products may only be found in US/Canada - still I have since found that a company called Zinsser does similar ranges. Jul 4, 2011 at 7:15

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