Knot in Plywood Showing Through Paint


TomInNC

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I made some cabinets, and one of the applied panels had a knot in it. Before finishing, I filled it with Durham's putty and sanded it flush. After applying a few coats of paint with an HVLP system (see below) there is a slight indentation where the knot was filled. It is almost as if the filler shrank after sanding. The options I have come up with are (1) lay the cabinet down, brush paint over the knot to level it, sand back and respray (2) just keep spraying, focus on the knot area, and hope it disappears (3) put putty in the indentation and sand flush, or (4) live with it. I am a little reluctant to go with (3) because I feel like something with the putty may have caused this issue to start with. (2) seems like it will only work if I somehow manage to get the spray to concentrate in the area of the knot and not around it. I am not under any time pressure, so I am inclined to try (1). Has anyone had any success (or failures) with any of these approaches for dealing with imperfections?

Cabinet.jpg

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On 12/6/2023 at 10:56 AM, gee-dub said:

Primer.  At this point you may be able to get away with some shellac or shellac based primer followed by a touch up.  I never expect paint to cover knots, stains or sap marks no matter what the claims are on the can.  Primer is your friend.

Thanks. Are you suggesting to prime the entire side of the cabinet, or just the area around the knot. For what it's worth, this is the water-based GF milk paint product, and the spec sheet just said primer isn't needed with wood, so I'm not sure what would play nicely with the paint. 

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I was just talking about a spot fix.  That is, prime or seal the offending area and then re-paint that area.  I always have some Zinssers Seal Coat around so that is what I reach for.  A spray shellac or something like BIN or 1-2-3 would be my choice.  

It is hard to tell from the pic as to whether you will be able to blend in the re-paint via a brush or not.  I am not well skilled in spraying but I often have trouble spot fixing using a gun.  Your product, gloss level and so forth will all play into that.  You could practice on some scrap to help you choose the best method.

One thing is for sure, you want to fix that :) (<--- that was supposed to be good natured and supporting).

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On 12/6/2023 at 11:55 AM, gee-dub said:

I was just talking about a spot fix.  That is, prime or seal the offending area and then re-paint that area.  I always have some Zinssers Seal Coat around so that is what I reach for.  A spray shellac or something like BIN or 1-2-3 would be my choice.  

It is hard to tell from the pic as to whether you will be able to blend in the re-paint via a brush or not.  I am not well skilled in spraying but I often have trouble spot fixing using a gun.  Your product, gloss level and so forth will all play into that.  You could practice on some scrap to help you choose the best method.

One thing is for sure, you want to fix that :) (<--- that was supposed to be good natured and supporting).

Thanks. I have some Zinsers at home as well. I know it's hard to tell in the picture, but the knot is physically below the rest of the plywood (i.e. it's  a divot). Will shellac actually help level that? 

I have no problem re-spraying that side of the piece. I have to spray the drawer fronts anyway, and it only takes 2-3 minutes to spray the entire panel with the knot after the gun is setup. 

 

 

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Search for autobody glazing putty on Amazon.  Here's an exampe:   https://www.amazon.com/Ready-Use-Red-Glazing-Putty/dp/B000AMOEH8/ref=sr_1_6?keywords=auto+body+glazing+putty&qid=1701885482&sr=8-6   Do your sanding with a backup block.  Fingers on sandpaper will dig it out again.

You're going to need to respray the whole front.  I go to lengths to avoid using anything with a knot in it for such things.  Dealing with hiding a knot is always more trouble than it takes to avoid them to start with.

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On 12/6/2023 at 9:06 AM, TomInNC said:

Thanks. I have some Zinsers at home as well. I know it's hard to tell in the picture, but the knot is physically below the rest of the plywood (i.e. it's  a divot). Will shellac actually help level that? 

I have no problem re-spraying that side of the piece. I have to spray the drawer fronts anyway, and it only takes 2-3 minutes to spray the entire panel with the knot after the gun is setup. 

 

 

Sorry, I overlooked that.  The shellac will not fill the void.  Timber Mate is my go-to for small spot fillers.

On 12/6/2023 at 10:01 AM, Tom King said:

Search for autobody glazing putty on Amazon.  Here's an exampe:   https://www.amazon.com/Ready-Use-Red-Glazing-Putty/dp/B000AMOEH8/ref=sr_1_6?keywords=auto+body+glazing+putty&qid=1701885482&sr=8-6   Do your sanding with a backup block.  Fingers on sandpaper will dig it out again.

You're going to need to respray the whole front.  I go to lengths to avoid using anything with a knot in it for such things.  Dealing with hiding a knot is always more trouble than it takes to avoid them to start with.

I would listen to anyone who has some spray experience.   If Tom says a whole surface re-spray after repair is the best solution, I would do that. :)

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On 12/6/2023 at 1:01 PM, Tom King said:

Search for autobody glazing putty on Amazon.  Here's an exampe:   https://www.amazon.com/Ready-Use-Red-Glazing-Putty/dp/B000AMOEH8/ref=sr_1_6?keywords=auto+body+glazing+putty&qid=1701885482&sr=8-6   Do your sanding with a backup block.  Fingers on sandpaper will dig it out again.

You're going to need to respray the whole front.  I go to lengths to avoid using anything with a knot in it for such things.  Dealing with hiding a knot is always more trouble than it takes to avoid them to start with.

Ok. Off to the auto body store...

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Just wanted to say thanks for the help. I used the Bondo glazing putty to refill the knot and covered the putty with some primer. After respraying, it looks 1000 times better. 

 

I am going to be using a top coat of General Finishes High Performance to add a little sheen. General finishes says you don't have to use a top coat with their milk paint product. That said, is it ok to only apply the High Performance to portions of the cabinet that will be seen? I know only finishing one side of something is a bad idea, but in this case the entire cabinet is already covered in paint.

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