Filling knot rot etc.

[Craig D Peltier]

I have some walnut that I want to fill a hole in that has small knot rot in it. Im wondering if anyone here remembers the WW show with David Marks that he showed on how to do this. If I remeber correctly it was epoxy with sawdust an maybe some tint.
Its on a + shaped dining room table leg. Its not in the darkest part of the walnut either.
The wood will be clearcoated.

[Scott Holmes]

Can you show us a picture? I think epoxy is the way to go; I may add a bit of color to help hide it, can't tell until I see it... I don't usually add saw dust because it looks like saw dust in the epoxy.

[Randy Walker]

Hi Craig
This one is dirt simple. Here is a recipe that I have used successfully literally hundreds of times.
Start off with some clean saw or sanding dust. I prefer black walnut or cherry. Next a dollop of polyurethane glue, and a tiny sprits’ of water. Mix enough of the two to make a loose paste and smear it into the offending gap. Now put a piece of tape over it and let it cure. I usually try to wait over night. The next morning I remove the tape and use a sharp chisel to pare off as much as I can, then sand it flush. The glue will have expanded down into the knot or open spaces, locking them in place. It will take some stain and will finish as nice as the surrounding wood.

Good luck
Randy Walker

[Scott Holmes]

Randy,

I had not heard of this type of GLUE and sawdust fix... Having never tried this; I have a few questions.

Does the tape keep the urethane glue from foaming? The foam has almost no strength. Does it really stains up well? Is this for loose knots? and/or for cracks that need to be filled?

[Ken Fitzgerald]

Craig,

One of the tricks turners use to fill holes or punky wood is to take either instant coffee crystals or coffee grounds mix them with epoxy and fill a hole.

If the wood is just punky or soft, you can do the same thing and thin the epoxy with denatured alcohol. It will thin the epoxy and it can be somewhat absorbed by the punky wood and stiffens or hardens it, if you will.

I would use an epoxy with a 20 or 30 minute working time so you have time to use it and don't have to rush.

In either case, we then are able to turn the wood using standard turning tools and techniques.

[Randy Walker]

Hi Scott
The tape forces the expansion of the glue down into the woods cracks and pores.
As to stain acceptance. No it only allows pigmented stains to lodge in the pores, so it only accepts some stain, however being in a knot it still looks great. It does however finish great with any finish I’ve tried (blo, shellac, lacquer, ob polly, Watco, ect.)
I have used this process hundreds of times. I use it on wide cracks and bug holes. I’ve used it to fill oopses and tons of other voids in wood. Black walnut dust works on 90% of woods, dark or light (even maple). Some woods like Bois D’ arc and cedar have lighter more reddish inclusions which is where the cherry comes in.
The first time I used it was on some great knotty pine. I got a great buy on construction grade 1x12s. Six month later when I got a chance to work with it the knots were falling out. I came up with this in a last ditch act of desperaction.
Hopes this helps. Give it a try I’m sure you will be impressed with it.

Randy Walker