will knots in wood mess up planer blades?

[Mike Gager]

knots in wood seem to really nick the blades when im hand planing, i was wondering if they have the same effect on planer blades as im thinking about getting one but dont want to have to replace blades all the time

[Jim Becker]

Yes, knots can damage jointer/planer knives the same as they can with hand planes. Take very light cuts to minimize this and be prepared to shift one or two of the knives laterally after milling the knotty lumber to keep from marking future wood while the knives are still serviceable.

[Richard M. Wolfe]

Mike, power planing knots is an issue for both machine and lumber. Knots are usually very hard and can cause issues with knives, as Jim said. Also, and I'm thinking mainly about aromatic cedar here as I plane a good bit of it, the grain change around the knots can cause a lot of tearout. And with knots a planer knife will occasionally pull one loose and that can cause havoc, from jamming in the planer to the point where you have to tear it down partially to get the knot out to bending or knocking something out of alignment.

In knotty wood take very shallow cuts and be prepared nonetheless to deal with some "knotty" problems.

[Jesse Cloud]

Yeppers. I've had the darn things "explode" in the planer - quite a racket even with ear protection.

I will knock or drill most knots out now and fill with epoxy after milling, then clean with a scraper and sandpaper.

[Mike Gager]

thanks guys. i made a somewhat similar post in the hand tools section about my knot problem with hand planes, i was hoping it wasnt as big a problem with the machine planers :(

ok cutting them out sounds like a good alternative, what type of epoxy would i use to fill the holes? is there a specific wood epoxy? sorry if thats a dumb question ive never used epoxy before or paid much attention to it at stores

[Mike Gager]

well i got some epoxy and i drilled out the knots with a forstner bit and put the epoxy in the hole and it looks like poo

not sure what your supposed to do with the epoxy but it just turned into a big mess.

oh also the epoxy i got came in a little twin tube thing with a plunger where you press the plunger and the two ingriediants shoot out and you mix them together but i used about 1/2 the tube on 2 holes so im thinking i got the wrong stuff anyways

[Tom Veatch]

...ok cutting them out sounds like a good alternative, what type of epoxy would i use to fill the holes? is there a specific wood epoxy?...

There are a number of products on the market that are designed for repair of rotted/decayed wood. One of those is the first thing I'd think about. Do a Google Search for "epoxy wood repair" and you should get a number of references.

[Mike Gager]

thanks tom, will do

also good to see another kansas woodworker on the board!

[Jacob Reverb]

Get yourself a gallon- or 3-gallon kit from West System or Raka.

The stuff has a shelf life of decades, but believe me, once you know how, you'll use it up.