Jointing with Planer Sans Sled
How thick does a planer sled need to be to joint lumber on a thickness planer. The answer, surprisingly enough, is zero.
Here's what I did yesterday. I took a couple of boards with twist in them. One was pretty bad. And I applied blue tape to the bottom side of the high corners. I guessed at about how many layers I'd need and started off with small strips of blue tape (1" wide by about 1" long) and layered longer and longer strips along the edge, building up thickness until the board lay flat without rocking on my reference table. I planned it out so that the final piece of tape ran nearly half the length of the board. Then I ran it through the planer, and it came out flat! No twist! Then I removed the tape, flipped the board over and ran it through again to get some perfectly flat boards.
A couple of tricks I learned is to alternate corners with your pieces of tape to build up both corners evenly. Then, if you only need a half thickness piece of tape, just apply it to one corner. It also helps if you're building up several layers of tape, like 7 (rough guess) or more, to go ahead and put an extra layer of tape down after you've got it flat, as the pressure rollers will compress the tape a bit. Once you've made enough passes to tell if the board is coming out flat, check it for flatness and apply or remove layers of tape as necessary before making your final pass.
Now, is this as good as a planer sled? No. It's more time consuming and it'll cost more in the long run. But it is an option that works should you need it. So like, if you normally joint on a 6" jointer and run into a rare 12" wide piece of stock, or if you have a 5' long planer sled but need to joint a rare 12' board (which would be heavy enough before adding a thick, 12' planer sled), this may be a good option for you to avoid having to build a new planer sled just for one or two boards. Just another tool for your bag, if you ever need it.
