African Padauk

[Keith Stephens]

Frequently Padauk boards will have a white powder like substance on the face. Usually this material disappears during the working process and is no issue. I have customer who completed several furniture pieces. On one piece, a cabinet with sliding doors, a white powder like substance is now appearing.
The cabinet was finished with Watco Oil. The white substance can be wiped off simply by rubbing but in a few days it reappears.

What is the cause?
How can the finish be repaired?
What will prevent this from happening again?

Thanks for any help or suggestions.

Keith Stephens
Woodworkers Source (http://www.woodworkerssource.com/)