Personally I would drill and chisel out the soft part and then epoxy. But thats just me.

 

Drill it out and replace it with a walnut dowel and use a no set saw to cut it flush.
I like the results I got. YMMV

 

I agree. Scrape out the soft stuff and then fill it with epoxy. You could tint the epoxy if you want, but personally I probably wouldn't bother doing that.

 

Use a tinted slow setting epoxy.
If you dig it out then you'll have to fill it.
I would leave the punky wood in there. And use epoxy as a hardener
Good Luck

 

I'd go with a thinner epoxy type resin, maybe something like Minwax Wood hardener? Or a water thin consistency epoxy form another company?

Then fill with the black epoxy, like you were thinking.

I know everyone hates Minwax, but I've had good luck over the years with wood hardener.

 

Epoxy would work but I find it messy.

You idea about using CA glue (medium or thick) would work well. For the actual application I would start with an application of thin CA immediately followed by the medium or thick CA. The thin acts as a wick, soaking the fibers and drawing the thicker glue in. Keep adding the thicker glue until it takes no more. Watch for bubbles rising to the surface and let it cure naturally….no accelerator. Curing might take several hours.

Be aware that neither epoxy or CA will accept a stain and if a oil type finish (BLO or Tung type) is used the knot will stand out as a "shiny" spot. It will blend in fine with a hard finish like poly, lacquer, varnish, or shellac.

Looking at the board again, it looks like it will need some planing. If you put the CA or epoxy on before planing there is a good possibility it will chip out. In that case I might just put some shellac (dewaxed) on the knot fibers to stiffen them for planing process. If you don't have shellac just use the thin CA glue to stiffen the soft fibers. When the planing is done you can use the thick CA or epoxy.

 

I would cut it out or route it out and replace it with a piece that is representative of that grain.
Otherwise, it's just going to look like a big black spot.

 

Another vote for epoxy - tinted a dark brown. Tape the back to prevent leakage and fill slightly proud with epoxy. After it has been sanded back down flush, you probably won't even be able to tell it was filled.

(and nobody else would either until you tell them

Cheers,
Brad

 

Liquid glass epoxy is all the rage nowadays, but if that was mine I would cut it all out and insert a good piece with a similar grain pattern. trying to get that white sponge to colour match will be a job for a skilled man, not for a first attempt.

 

If you cut that knot out, the whorl the grain makes is gonna be hard to match. Depending on the kind of piece, either embrace the imperfection, and leave it as character, either with or without that scab that is gonna fall out, just when is the only question.

Either that or grab another chunk of wood, or work around the knot.

 

I make bandsaw boxes, and love knotty wood as it makes the boxes stand out, as you can see

But on a long run table top that knot is the only thing anyone will see. If at all possible, use another plank.
Then you can play with that bit as you wish.

 

Since it is going to catch your eye anyway, maybe stick a contrasting bow tie over it.

 

Dig out the soft material. Get some walnut wood filler from the BORG and fill it in. I've found that the wood filler works just fine, even on knots that size and you don't have to mess with tinting epoxy

 

If it was me, I'd dig that knot out and then I'd put in colored epoxy; color is dependent on the effect desired.

I'll admit to liking "out of the box" colors when using this technique. Here's a photo of the arm of a rocking chair in which a void has been filled with colored epoxy. This particular piece of wood had a void that went clear through the 8/4 piece of wood. It's filled on the bottom with epoxy tinted with ground coffee and then a mixed acrylic in the upper portion.

 

For me, I'd just mix up some 2:1 and pour it in without bothering to do anything to the knot.

As it soaked in, and it will, I'd add more, until I had it flush with the rest of the surface.

If desired, like Ray's, add color, be it a striking color or black, to make it look more like the natural wood.

Even clear epoxy can work in some situations. No one notices the grain running in the wrong direction on this one:

 

Wow, lots of great insights, thanks guys. To provide some additional context, this isn't a table top… it's more of a countertop for a built-in… it's going on a set of base cabinets in the corner of my living room that will than have a large set of bookshelves installed on the back section. Here's a very messy in progress photo:

And a couple more photos of the wood for the top:

and a scale shot of the knot:

So, it's not something that will be in the center of a room like a coffee table where the knot will be attention grabbing, not that that would be bad. If the wood wasn't so punky and soft I'd probably be less concerned, it's just the texture and stability has my attention.

Cutting it out and replacing with a fill piece is interesting… all my boards are a little long, so I'll have the native material for it. However, I fear I may lack the skills and tools for that. I'm a DIY woodworker, with a good Metabo table saw, a good dewalt miter saw, and a cheap router and band saw (among other loose tools). I'm good for a DIY guy and I figure stuff out really well (thx internet!), but it's often my first time doing many more complex woodworking skills.

Colored epoxy is interesting, but I don't think that's my cup of tea… I'm looking to keep things completely natural, or as natural as I can.

Another plank also isn't an option… while I could certainly buy one, it's around $12 / bf, and I'm not looking to spend that much more on materials for the top. Besides, other than the knot that is the best looking board I have… the heartwood and patterns on that side are awesome.

So, the easiest route for me is probably keeping it as is and just making it look as good as I can. On that note, what about using a combination of low and medium viscosity clear CA (or black CA) to penetrate/harden/seal it, then mixing a bunch of heartwood sawdust in over the punky part? Once I sand it down I would imagine the exposed sawdust will take stain with the rest of the top, making it more uniform? I plan to coat it with a water poly at the end, so that should ensure a uniform finish… right?

Thanks again for all the tips and insights, really appreciate it. I haven't worked with black walnut before, and given the cost I'm paranoid about screwing it up.

Best,
Rick

 

I would leave the knot also. I turn a lot of wood and run into issues like this a lot. 2 options - use a thin type 2 part epoxy that will soak into the wood, and then fill above board level so it can be flattened, or use thin ca to harden the soft part, then fill above board with a std thick 2 part epoxy. You want epoxy not ca as part of the finish, if possible. I would color the epoxy and/or ca. Epoxy is easier to color and get a bubble free finish. Pick the color. Neither clear epoxy or ca looks worth a damn. I would not fill completely with black ca, will leave a big black spot.

 

"So, the easiest route for me is probably keeping it as is and just making it look as good as I can. On that note, what about using a combination of low and medium viscosity clear CA (or black CA) to penetrate/harden/seal it, then mixing a bunch of heartwood sawdust in over the punky part? Once I sand it down I would imagine the exposed sawdust will take stain with the rest of the top, making it more uniform? I plan to coat it with a water poly at the end, so that should ensure a uniform finish… right?"

It this is the way you want to proceed I would recommend packing any voids with the sawdust before applying the CA glue. I collect my sawdust using a sander with a collection bag attached (orbital or belt sander). The sawdust will appear lighter until it is moistened by the glue….do a test to see if you like the color of the sawdust and glue together.
Then as I mentioned above, apply the thin CA followed IMMEDIATELY with the thick CA. The thin will wick the thick in. Otherwise the thick CA may not penetrate all the way before it sets up. Keep adding thick until the void takes no more and let cure over night. Sanding it down may expose the sawdust but the thin CA will have penetrated so it will NOT take a stain at that point.

Do you actually plan on staining Black Walnut…..Why…to blend in the various shades of the boards??? That will occur over time and the dark walnut color will gradually get lighter.

 

In terms of the repair, I'm exploring different options that balance end results with effort and what I think I can achieve. I'm actually leaning more towards using epoxy and keeping the knot intact… preserving it but sealing it, maybe staining it directly in advance (or just coloring the epoxy) to blend it with what I plan for the countertop to look like.

As for why I'm staining it, because I want to accentuate the grain patterns in the wood while also reducing the yellows/reds and accentuating the lighter and darker tones (to make the patterning more dramatic). I've done a lot of research, and from the examples I've seen I like that look the most. I think finishes that accentuate the reds/yellows in the wood look dated and less contemporary. Just personal taste.

Best,
Rick

 

Knots like that are a good candidate for Starbond medium black CA. It will soak into the soft wood, stabilized it and fill any other gaps too. I also like to carve out spongy wood or the frass from beetle tunnels and fill them with turquoise sand. I pile the turquoise into recesses and cracks and then dribble medium CA on it to lock and fill the spaces around the sand. I usually pile it just a little proud of the surface and then use dremel burrs and sanding drums to mostly level it and then sand it smooth. You can buy a small bag of the sand on Amazon. An ounce will go farther than you would expect. Turquoise looks great in walnut but will dress up even light colored woods.

 

well for me i love that kind of "imperfection" id never try to remove it or do a patch or what ever.embrace it and id soak it with ca glue or very thin epoxy probably a dark brown or black.i go out of my way to save that kind of thing.to me that is beauty not a blemish.clear grain wood is boring.

 

I like imperfections as well, but not punky, funky ones like that.
Since you're staining anyway forget the epoxy, just dig it all out, fill it with walnut putty, marker in some grain lines with pencil, colored pencils, or whatever Rich recommends using.
Then move that board to the back.