Tim Ward wrote:


Well, on sailplanes, anyway, you sand to make sure the airfoil is the
right
shape, (shrinkage can occur over the spars after some time out of the
molds), and to make sure that any waves in the contour are less than
..004
inches.


That's another reason to try scraping. Scrapers can be filed to a
particular curve for just that sort of work.

--

FF