How do keep knots in boards?

[Randall J Cox]

I bought about eight 5/8" thick 8" wide cedar boards to cut up and use for slats to rebuild my mountain cabin deck railing. They have lots of knots in them How can I make sure they don't fall out later on? The slats will only be about 2.5"-4" wide. Thought I read years ago painting each knot with shellac might help but my memory is very faulty. The slats will be oil primed and painted before installation. Any ideas? Randy

[Mike Henderson]

If the knot is loose, I usually use some epoxy to glue it in.

Mike

[Doug Garson]

For that application I think you would be better off using straight grain, clear cedar.

[Jimmy Harris]

It depends on the knot. If the knot is loose, you'll probably want to fill the gaps with epoxy and sand it back. If the knot isn't loose, then often times shellac or whatever finish you use acts like a glue to keep it secured in place. Either way, you're going to be taking some risks. In a knot, the grain runs perpendicular to the rest of the wood, so it'll expand and contract in different directions and at different rates than the rest of the wood, which can allow it to work itself free over time.

But I've built lots of things with knotty wood, and I've never had issues. But my projects were designed with the knots in mind, so the knot could fail and not render the piece unusable. And I don't know that I'd want to use them on a deck where they'd be exposed to sun, rain, and drastic temperature fluctuations. That would be asking for problems. So if you go this route, I'd make sure to build it with the idea that the knot will work its way free on day, and won't compromise the integrity, usefulness, or look of the deck rails. And then take your chances with the outcome.

[Brian Tymchak]

I bought about eight 5/8" thick 8" wide cedar boards to cut up and use for slats to rebuild my mountain cabin deck railing. They have lots of knots in them How can I make sure they don't fall out later on? The slats will only be about 2.5"-4" wide. Thought I read years ago painting each knot with shellac might help but my memory is very faulty. The slats will be oil primed and painted before installation. Any ideas? Randy

That sounds like advice to seal knots to keep them from leaking sap, or absorbing moisture.

[Andrew Hughes]

In California you can get a grade of cedar STk
Small tight knots or sound tight knots. It grades the wood with knots that most likely won’t fall out. That’s a better choice
The other solution I can think of is to flatten out soup cans and nail them to the underside of the worse looking knots
Good Luck

[Mike Henderson]

When I replied, I was thinking of aromatic cedar.

Mike

[John Kananis]

I've mixed coffee grinds with epoxy on some bigger knots. The grinds are nice for filler.

[Bill Howatt]

Sounds like a bit of a crapshoot. If the knots are loose, I'd use epoxy, if the knots are tight, I'd drench in thin CA glue.
I wonder if putting an additional thin coating of epoxy on the underside would help; since it's being painted and underneath appearance isn't an issue.

[David Walser]

Randy -- When I worked in a furniture mill, we had a line of rustic furniture that was made from knotty pine. We used hot glue, applied to the back side, to keep the knots in place. Most hot glues are flexible, so the hot glue worked well given the different amount of contraction/expansion you'd expect between the knot and the surrounding timber. Hot glue is also quicker than mixing up epoxy and is far less expensive.

HTH

[Larry Edgerton]

Randy -- When I worked in a furniture mill, we had a line of rustic furniture that was made from knotty pine. We used hot glue, applied to the back side, to keep the knots in place. Most hot glues are flexible, so the hot glue worked well given the different amount of contraction/expansion you'd expect between the knot and the surrounding timber. Hot glue is also quicker than mixing up epoxy and is far less expensive.

HTH

Roo Glue works as well, stays flexible and dries clear.