Great articles. Thanks for the testing info.

From your final update and summary -

"Most of these samples eventually failed at the edges of the boards next to the bedstrips."

"Expansion of the boards due to weather changes may have caused the bedstrips to become tight against the edges of the boards. The extreme amount of rain and snow in the last 8 months probably caused the boards to expand and possibly weakened the finish next to the bedstrips."

"Be sure to allow clearance between the strips and the wood to allow for expansion...."

How much clearance, if any, between the bottom of the bed strip that fits into the deeper grooves in the wood. Not the flat area on the bottom of the bed strip, but I'll call them the two sharp edges on the bottom of the bed strip.

Is it possible these "edges" are cutting into the wood or removing the finish during movement/expansion?

Should the flat area on the bottom of the bed strip touch the wood before the 2 edges? Or touch at the same time?

-Tom

1950 Chevy 3100 w/ 1956 235