If you have not seen it, the Jul/Aug ’07 issue of Fine WoodWorking has a good article titled, “How strong is your glue?” There were two interesting takeaways for me.
First, being a big fan of epoxy, I was surprised to see a Type I PVA (Titebond III) outperformed epoxy in tight and snug joints and only was slight worst in a loose joint. Seeing that it is far less expensive and easier to use, think I’ll be using more Titebond III in the future.
Second, the poor performance of polyurethane glue (Gorilla Glue). In tight and snug joint the Titebond III was 20-40% stronger. In a loose joint the Gorilla glue was just plain “crap”.
The article includes break force data.