Advice on filling BIG knot holes?

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Forum topic by Willeh posted 04-18-2013 10:12 PM 12346 views 0 times favorited 16 replies Add to Favorites Watch
View Willeh's profile


228 posts in 2335 days

04-18-2013 10:12 PM

Topic tags/keywords: question

Getting into my Roubo bench build, (See blog about the build here: )

a few of the pieces that I had for the top have some pretty significant knot holes:

Now, for the most part, these will end up on the bottom out in the middle where they shouldnt be an issue, but, for the sake of it, I would like to fill them up to seal them and avoid having too much of a weak spot in the bench.

I’ve never really had to fill big imperfections before and was wondering if any of you had suggesions on what to do here?

Do i carve a piece that will fill most of the hollow and then fill with some sort of epoxy? if so, what epoxy do you suggest? (I’ve never really had to use any before)

Much appreciated!


-- Will, Ontario Canada. "I can do fast, cheap and good, but you can only pick two... "

16 replies so far

View richardwootton's profile


1699 posts in 1951 days

#1 posted 04-18-2013 11:59 PM

Do you have other pieces that you could use for the top, or do to have to use these boards? I’ve never filled knot holes quite that large, but I have used epoxy on smaller knots in the past with relatively good success.

-- Richard, Hot Springs, Ar -- Galoot In Training

View AandCstyle's profile


3051 posts in 2253 days

#2 posted 04-19-2013 12:03 AM

Will, take a look at this one. I haven’t used it, but it gets good reviews and Jamestown is a good company. HTH

-- Art

View grfrazee's profile


388 posts in 2135 days

#3 posted 04-19-2013 12:04 AM

Using epoxy in that much volume will generate a lot of heat when it’s curing. I don’t think that would be a big problem, but there is the chance it may crack the boards.

Personally, it looks like you have enough clear wood for the top based on your blog. There will be enough wood glued to the sides of these pieces that these voids will not substantially weaken the top.

If you’re really set on filling them, probably the best option is to square off the area around the knot holes and fill in with a smaller piece.

-- -=Pride is not a sin=-

View Klickitat's profile


51 posts in 1866 days

#4 posted 04-19-2013 12:27 AM

I would put the top together, then drill out the knots with a hole saw and glue in a corresponding sized dowel in a contrasting color. I think something like that would look really good. Also a round dowel on the joints going all the way through would add strength to the joint.

View ,'s profile


2387 posts in 3543 days

#5 posted 04-19-2013 12:27 AM

In mesquite we find large holes, knots, worm holes, etc… I use fiberglass resin that is sold at Lowes or home depot. I follow the directions on the label except I go ahead and add saw dust in the resin to add substance and to thicken the product to my desired thickness. Dries fairly fast and dries very hard. Can be used to fill large areas. I try to be neat when working with it so I can avoid any excessive sanding when it is completely dried. Sanding the resin is not easy. Otherwise it works very well for us.

-- .

View Joe Lyddon's profile

Joe Lyddon

10096 posts in 4048 days

#6 posted 04-19-2013 12:58 AM

Matching sawdust mixed with epoxy or resin… I like epoxy…

I went to HD and searched for FAMOWOOD (good stuff fr pouring epoxy table tops, etc.)
and found THIS STUFF, which looks really GOOD!

-- Have Fun! Joe Lyddon - Alta Loma, CA USA - Home: ... My Small Gallery:"

View Sandblastguy's profile


42 posts in 2107 days

#7 posted 04-19-2013 12:25 PM

Fill them with Bondo automotive body fill. Sounds crazy but works great its weather proof won’t crack won’t fall out and it dries fast and sands easy. I use it all the time and have never had a problem with it.

-- Sandblastguy Orangeville On. Creating Art From Nature

View Lee Barker's profile

Lee Barker

2170 posts in 2846 days

#8 posted 04-19-2013 01:24 PM

+1 for Bondo. I can see no need to go with the expense, mess and sanding difficulty that epoxy products present.



-- " his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View CharlieM1958's profile


16274 posts in 4214 days

#9 posted 04-19-2013 01:42 PM

Another vote for Bondo.

-- Charlie M. "Woodworking - patience = firewood"

View Mip's profile


453 posts in 2074 days

#10 posted 04-19-2013 02:18 PM

I agree with Lee Barker and CharlieM1958. I used to work at a building site in South Lyon, Michigan, and we used it all the time to fill dents in steel entry doors. Just overfill it a bit, sand it, paint it, done. The only problem with using it on your workbench is that the color is pink when dry, but you could put those filled in boards on the bottom side. I just looked at prices for bondo: 6$ for a guart versus $26 for 12 oz for the products mentioned here.

View Smitty_Cabinetshop's profile


15348 posts in 2614 days

#11 posted 04-19-2013 02:22 PM

I would be inclined to chisel or route the junk out and glue in donor pieces.

-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive --

View RodNGun's profile


118 posts in 2299 days

#12 posted 04-19-2013 04:25 PM

+1 for drill (or router) and glue in plugs

View Willeh's profile


228 posts in 2335 days

#13 posted 04-20-2013 08:38 PM

thanks for the advice on this guys! I think i will drill and plug as best i can and then epoxy anything that I cant.

Much appreciated!

-- Will, Ontario Canada. "I can do fast, cheap and good, but you can only pick two... "

View kdc68's profile


2657 posts in 2272 days

#14 posted 04-20-2013 08:45 PM

Willeh...You could make your patch a bit decorative by using a dutchmen…

-- Measure "at least" twice and cut once

View Willeh's profile


228 posts in 2335 days

#15 posted 04-20-2013 11:16 PM

kdc68: A dutchmen?

-- Will, Ontario Canada. "I can do fast, cheap and good, but you can only pick two... "

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