Knot holes bleed through painted fascia boards

When replacing my fascia boards, I primed them with a non-shellac-based primer. Now, the knot holes show just a couple of days after applying two finish coats. Can I get away with spot priming the knots with shellac right over the existing finish coats, then applying new finish coats? Or must I first sand the knotted areas down to bare wood?
Thanks,
Ray
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When replacing my fascia boards, I primed them with a non-shellac-based primer. Now, the knot holes show just a couple of days after applying two finish coats. Can I get away with spot priming the knots with shellac right over the existing finish coats, then applying new finish coats? Or must I first sand the knotted areas down to bare wood?
Thanks,
Ray
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I'd sure try spot priming first, to see if it works, before going to the effort of sanding down to bare wood.
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Doug Miller wrote:

The problem is than new gutters are going up in two days, and I want everything to be okay for sure by then. Yes, the gutters will cover the knot stains, anyway, but still I prefer to treat them right.
Ray
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Ray K wrote:

Rent a power sander. Do it right. Shellac will dry in a few hours.
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William W. Plummer wrote:

I don't even have to rent one: I already own one. I guess I'll just bite the bullet and sand. There really aren't that many knots; in 156' of fascia, there are perhaps 15 knots.
Thanks,
Ray
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<< Rent a power sander. Do it right. Shellac will dry in a few hours. >>
Why sand it? Slop on some paint remover over all 15 knots, go back and scrape each one clean. cover with shellac or whatever and paint to suit. Time elapsed, maybe 30 minutes, no fuss. HTH
Joe
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Turn out that Zinzer makes a pigmented shellac primer that they claim will adhere to even glossy paint. My paint is satin finish. It worked just fine. After two days, no more bleed. Before using the shellac, bleed would occur within two days. So it looks the problem is solved.
Thanks,
Ray
Joe Bobst wrote:

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