clear filling knot holes

Dave Black

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Location
Central PA
I am working on a rustic table and have some knot holes to fill, I have used 2 part 5 minute clear expoy in the past and it worked ok, is there anything better to use?
 
In a video by David Marks, he shows several options ... flood the knot area with cyanoacrylate to firm it up, then fill the voids with slow set epoxy which can be colored (sawdust of same wood, pigments, etc) to match the wood, several colors can be added and swirled in to give a more natural look .. or, if the knot is a big void, find a good knot of similar size, cut it out via a 1/8" think 'veneer' type slice and inlay it ... or inlay some other wood in the knot area .. just some thoughts for you to consider ... best of luck.
 
Biggest problem with using epoxy or casting resins is air bubbles. I've found it best to use a longer setting filler (30 minutes or more) and over-filling the hole. That way, any bubbles will (hopefully) work their way to the surface before the filler cures.

Also, stir the filler carefully while mixing, so as not to introduce air into the mix, and finally, use a toothpick, or similar, to carefully 'butter the sides of the void before you pour the filler in. This will help maximize adhesion as well as minimize bubbles.

BTW, on darker woods, I often dye the epoxy black, using a Behlens brand powdered dye.
 
Guys, re-read the thread title. The OP is looking for a clear filler.

Then the polyester casting resin is probably the best choice, but the exposed (top) surface will cure somewhat sticky, so he'll need to overfill the recess and try to shave off the sticky top surface (it's only a few thou thick, anyway).
 
I found some 20 min epoxy at home depot and tried that it seemed to work ok but I did get some bubbles trapped. I overfilled the voids and scraped them down a few hours later, worked really well. On part of the table there are some bug holes , by some I mean a lot, so it will be some work to scrape them down. I'll have to see how it goes.
 
I scraped and sanded down the epoxy then sprayed lacquer on the table today. Except for some bubbles in the epoxy it worked really well. If there is another time I need to do this I think I will either try finding a thinner viscosity epoxy or mixing it up then putting it in a vacuum to pull the bubbles out before filling the knots.
 
I've used a touch of denatured alcohol to lower the viscosity of Borg epoxy with good results. I'd only do it for cosmetic fixes though, not structural ones, since I don't know how thinning it affects the strength.


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Im with the others in using West System. Ill also add a bit of Trans Tint or powdered dye to try and match any surrounding knots. If the knots or voids are small I will use Behlen's burn in sticks and try to match the finished stain so they blend out or again match the surrounding knots.
 
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