Is wood glue really stronger than wood? (shear/axial/bending stress tests)

[Triggy]

I read that wood glue is supposed to bond better than wood, which didn't jive with my physical intuition. I did some stress testing with various types of wood, and here are my results!

 

 

[DrP]

I test a glue product we manufacture and we do a simple joint strength test. We see it all the time with what you had with your cherry where it breaks at the glue line but rips off a veneer of wood from the other piece too.

 

 

[HB of CJ]

Wood is not that strong.  Some is OK for certain purposes.  Other types of wood for other purposes.  Historically it was used because it was available and wood dovetailed with the tech of the time.  Wood sailing ships come to mind.   Big wood framed buildings were also fine.   Wood glue has the potential to be stronger than the wood material it is gluing together but that depends upon the type, kind, size and grain direction of the wood employed.  Many variables.

Rich long human history with this.  Excellent subject and thank you.  The old wood glues required dead horses.  Also available then.

[Bender]

Wood is strongly anisotropic, which means it can be much stronger in the direction of the fibres. In your tests, you are using load cases which are very unfavourable for wood, which makes the comparison unfair.