Is Bondera Appropriate for a Penny Tile Backsplash?

Hi! I'm doing a penny tile backsplash in a kitchen. I wonder if Bondera would be a good material to use with copper pennies. I haven't felt confident in the bond I got when I tested some glues - too brittle, the penny pops off under a fingernail. Do you think Bondera would make secure backsplash?