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Gluing end grain is stronger than you think.

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Setch

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No he hasn't, he's confirmed that wood is stronger long grain than cross grain.

The end grain glue joints were the weakest in the test, as they were the *only* joints which failed. All other fractures were in the wood itself.

He's also failed to address the reason side grain to end grain joints are regarded with suspicion, which is differential movement causing the joint to separate after a period of exposure to shifting humidity.
 
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GerryT

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No he hasn't, he's confirmed that wood is stronger long grain than cross grain.

The end grain glue joints were the weakest in the test, as they were the *only* joints which failed. All other fractures were in the wood itself.

He's asleep failed to address the reason side grain to end grain joints are regarded with suspicion, which is differential movement causing the joint to separate after a period of exposure to shifting humidity.
I agree.
If the joint fails on the glue line without any failure in the wood then it shows only that the wood is stronger in that grain direction, but practical speaking the glue joint is weaker because it failed as Setch rightly points out.
 

Bristol_Rob

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No he hasn't, he's confirmed that wood is stronger long grain than cross grain.

The end grain glue joints were the weakest in the test, as they were the *only* joints which failed. All other fractures were in the wood itself.

He's also failed to address the reason side grain to end grain joints are regarded with suspicion, which is differential movement causing the joint to separate after a period of exposure to shifting humidity.
He did - the load at failure was higher in end grain to end grain.
 

Setch

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He did - the load at failure was higher in end grain to end grain.
But this is apple to orange territory again, the side grain to end grain joints were wood failure, not glueline failure.

In simple terms, if you don't have a piece wide enough for your purposes, you can glue it up without losing any strength relative to a single piece, in fact the glued piece may even be stronger.

If you have a piece too short, you *cannot* glue a bit on the end to make it longer without compromising strength compared to a single piece. This is why end grain joints are dismissed as weak, because they are weaker than the practical alternative ie: a longer bit of wood.

His results support this.

With regard to side grain to end grain joints, they can be plenty strong, but there strength is likely to degrade after a few seasons on movement, as the glueline deals with differential movement.
 

Inspector

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Some of the "can't glue end grain" is related to the glues many years ago not being as strong as more modern ones. Some of the epoxy structural adhesives would be the ones to test to see how they fair. Personally I will be sticking (little pun there) to tried and true practice until a proper glue company does the testing rather than another youtuber dude.
 

JobandKnock

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In recent years we have started to C24 structural softwood timbers with finger joints coming from Germany. Admittedly in sizes like 7 x 3 and 8 x 3in, not the biggest stuff we use, and only graded for interior use, but I think that does indicate something about modern glues used in a controlled environment
 
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TheTiddles

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So are you going to point out all his mistakes or just leave the sarky comment as is?
Load cells don’t directly measure force, they measure voltage and calculate force from it, graphs with no axes labels and I’m now bored of typing
 

Bob Chapman

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The comparisons need sorting out. He is comparing the strength of one glue joint with the strength of a different glue joint of the same area. In this comparison the end grain - end grain joint is stronger. A woodworker compares the strength of a glued up piece with the strength of a solid piece the same size. In this comparison the the side grain - side grain joint is stronger than the wood but the end grain - end grain joint is weaker than the wood. Therefore it’s worthwhile gluing narrow pieces together to make a wide piece but not worth gluing short pieces to make a long piece.
 

dzj

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I've seen dozens of stub tenoned kitchen cabinet doors fall apart over time.
Wouldn't happen if this end grain gluing was such a hot thing, would it?
Just like with a lot of these Youtube experiments, they don't revisit these joints after a couple
of years of everyday use. After a few annual cycles of moisture content change or
adolescent kids in the house.
 
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