"Swingman" wrote:

Used two part epoxy to glue the wood "backsplash" on this 'kitchen
desk' last year:

A month later someone apparently hit it with enough of a 'shear'
force to knock it loose and chip the granite, leaving 1/4" deep pits
where the glue had been applied. The granite chips were still neatly
bonded to the wood and the wood was not damaged, so it certainly
appears that the epoxy indeed weakened the granite?

Like you, my first impulse would have been epoxy; however, on 2nd
thought, the epoxy cured and provided a connection which transmitted
the impact to the granite, resulting in failure.

A good adhesive such as Sikaflex 291 or 3M 5200 would provide a good
bond while absorbing enough of the impact energy to avoid granite
failure.

IMHO, mechanical fasteners should be avoided.

If you do use them, make sure holes in granite have clearance to
provide float.

BTW, the epoxy didn't attack the granite, it was simply stronger in an
impact application.

HTH

Lew