# Sealing Knots



## LearningAsIGo (Mar 8, 2011)

I need to prime and paint some boards that have knots in them. I'm using dark paint, so I'm not sure if you will be able to tell if the knots bleed through?

Through googling I have seen that the general consensus seems to be that in order to seal knots you need to use BIN primer or else they will bleed through. I have definitely seen this with latex primer. Will knots bleed through oil based primer or can you use oil to seal them also?


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## Bonka (Apr 13, 2012)

Use Zissner's Seal Coat.


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## Cosmicsniper (Oct 2, 2009)

The BIN Primer is just dewaxed shellac, either clear or pigmented white. There are oil-based and latex primers out there, Kilz being one I have in stock. Rustoleum (Zinsser) also has water and oil-based variants.

The BIN primer will work regardless of the top-coat as shellac is universal in what can go on top of it, though I would typically use a water-based primer with a latex finish, like the aforementioned Kilz or the Rustoleum alternatives. However shellac is a better barrier than the other alternatives, so if you are priming to cover nasty odors or something, then I'd use the shellac-based BIN. Likewise, for your application, I'd stick with shellac…it's slightly better as a moisture barrier, but it also dries very fast…giving really runny knots little chance of affecting the primer as it dries (which could be a problem with the slow drying oil-based stuff).

The Zinsser Seal Coat mentioned by Jerry is essentially the same stuff as the BIN Primer, perhaps a little thinner than the Bin Primer (though that's just a guess on my part), and clear like typical shellac.


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## madts (Dec 30, 2011)

Try Putting some super glue on them. That will seal them and also keep them in place if they are loose.


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## LearningAsIGo (Mar 8, 2011)

I have Zinsser 123 latex based primer
Cover Stain oil based primer

I have a quarter of a can of bin but it's been sitting in the basement awhile and I'm not sure if it's usable.

Can I use one of these?


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## NiteWalker (May 7, 2011)

+1 more for zinsser BIN. That stuff is amazing.


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## RHolcomb (Mar 23, 2010)

Zinsser Bin is definitely the product to use. Get the Shellac based. The Latex stuff is good for general purpose priming but won't seal the knots


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## Rick Dennington (Aug 27, 2009)

If it was me, I'd seal the knots with epoxy….You didn't mention the type of wood you're using, but I'd mix up a little dust with the epoxy and fill them it…..good to go…...


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## LearningAsIGo (Mar 8, 2011)

The wood is dimensional lumber so probably douglas fir or whatever else they make it out of


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## kizerpea (Dec 2, 2011)

another ZINSSER b.i.n. here ..pine knots…. shellac based primer two coats an lookin good!!!!


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