the problem is that the clear coat was too hard or there was not enough surface prep to properly adhere the clear to the wood.

a super hard clear coat is terrible on old playfields with old inserts as you can not bullet proof wood with clear. I've had no problems with old playfields done by Bill Davis and people who have followed his style. I've had tons of problems with new fangled clear guys who deal with customers who cry about dimples.

-c