Well the soap has been sitting on the raw pine dish now for a few hours and not a hint of blackening. I think I have found that the problem was the oak. For what ever reason, the oak I was using for a soap dish reacted like it did, so I won't be using it any more for my soap. The pine dish however, is working wonderfully, so I will make more of those.
Thanks to every one who chimed in with ideas and suggestions. Seems the problem is solved.
Thanks to every one who chimed in with ideas and suggestions. Seems the problem is solved.