In the event you take note of the woodworking sphere on YouTube, you will have seen a video by Patrick Sullivan referred to as “Glue Myths: 1. Finish grain” (posted under). I’ve been a fan of Patrick’s movies for some time now (I extremely suggest his DIY DRO video). Even so, I scrolled proper previous this video once I was first served it per week in the past. I figured it was going to simply affirm what I already knew: Finish grain glue joints aren’t a fantastic concept.
Quickly after the emails, Instagram DMs, discussion board posts, and feedback began coming and coming, and I lastly watched the video. I used to be mistaken. The video didn’t affirm my beliefs.
First off, watch Patrick’s video:
Wow! Proper? Patrick’s strategies appear as sound as will be–though I’m certain a couple of engineers will argue in any other case within the feedback under (please do!).
My ideas and opinions are my very own right here, they usually’re nonetheless being fashioned the extra I take up the video and give it some thought. In Patrick’s testing, end-grain to end-grain joints carry out higher than side-grain to side-grain joints. I’ve a tough time arguing with the strategies, so I can’t argue with the outcomes. However I believe the web group is grossly overestimating what these outcomes imply. I can’t converse for Patrick*, however I believe he would agree that individuals are getting just a little too excited concerning the prospects afforded by a brand new world of end-grain to end-grain joints!
#1 – The outcomes aren’t that stunning
Anyone who has ever seen a 7-year previous karate chop a pine board in half is aware of that the wooden at all times splits between the lengthy grain fibers versus throughout them. What Patrick’s video reveals is simply that, with two added information factors; finish grain to lengthy grain and finish grain to finish grain.
In the event you take a look at the outcomes from Douglass Moore and Tom McKenna’s joint check article in 2009, you’ll see precisely the identical factor; joints virtually at all times fail when the lengthy grain fibers tear out. As they state within the article:
After we seemed intently at how joints tended to fail, we discovered a transparent correlation with our check outcomes. The stronger joints compelled their part items to fail by fracture throughout the grain or proper on the glue joint (miter), whereas with the intermediate-strength and weakest joints, failure occurred by the splitting of 1 piece alongside the grain.
The strongest joints are joints that work cohesively with the whole lot round to maintain the whole lot in place. In truth, Marc Spagnuolo posted a improbable response video (across the 5:30 mark) that drove this level residence properly.
#2 – Over time, I believe wooden motion would make all of this moot
Wooden goes to maneuver throughout its width. You possibly can’t cease it, so all your newfound cross-grain glue joints that carried out so effectively in Patrick’s video will not be prone to carry out that effectively after a 12 months or two of motion. I actually hope that Patrick units apart a couple of of those blanks to check in a 12 months or two. Even higher, I’d prefer to see the efficiency of those cross-grain glue-ups on a bigger scale.
#3 – I can’t bear in mind a time I want I might have gotten away with a butt joint.
For a similar causes I don’t use pocket screws as everlasting joinery, I can’t think about an occasion once I could be utilizing a butt joint in any piece of furnishings I cared about. Joinery not solely provides you the power you want for long-lasting furnishings, but it surely makes the whole lot simpler to assemble. In the event you’ve ever tried to maintain a glue-laden board completely in place whereas making use of the suitable clamping stress, you already know that it’s virtually an unimaginable process. Glue is slippery and people boards are going to maneuver in all places. Joinery holds the whole lot the place it’s presupposed to be.
Let me know within the feedback under how you’ll use an end-grain to end-grain joint, as a result of I can’t consider any examples.
#4 – I’ve to the rethink justification for my reply on solid-wood chess boards, however not the reply itself.
We really had this podcast clip sitting right here prepared for… effectively… this, I assume.
In episode 222, we mentioned a listener’s need to make a solid-wood chess board. One in all my essential justifications for advising that they not do that’s due to the weak spot of the end-grain joints that may end result. We got here up with a couple of strategies of working round the issue (rabbeting the joints and inlaying blocks right into a stable piece) however after watching Patrick’s video, I’m beginning to rethink this one explicit use case for end-grain glue joints. In the long run although, I nonetheless fear about wooden motion finally taking its toll on a chessboard. Patrick’s video actually makes me need to attempt to construct one although and I’m hoping to take action quickly. After all I’ll replace the weblog studying viewers!
Like Marc stated in his video, possibly we should always all cease saying that there is no such thing as a power added to a joint by including glue to the shoulder of a tenon or finish grain of a dovetail. It’s virtually cliche at this level, however virtually everybody glues that finish grain after which extols the pointlessness of it. There’s clearly some, if not a good quantity of power added. Is it definitely worth the squeeze-out it’ll trigger? Or is the reply like the whole lot else in woodworking—possibly?
*Patrick, in the event you learn this, we’d like to have you ever on the podcast to debate your video! E mail us ([email protected])!