What type of patch should be used for small holes in thin plywood skin if the skin is less than 1/10th inch thick?

The most appropriate choice for repairing small holes in thin plywood skin that is less than 1/10th inch thick is to use a splayed patch if the hole can be cleared out. This type of patch involves removing material around the hole such that the edges are tapered or sloped, which allows the patch to blend more smoothly with the surrounding panel. The design of a splayed patch helps distribute stress over a larger surface area, minimizing the risk of failure and ensuring that loads are shared between the patch and the original structure.

In the context of thin plywood, where the material may be more susceptible to cracking or splitting, a splayed patch provides a better reinforcement and integrates more effectively with thin skins without adding excessive weight or compromising structural integrity.

Other methods like scarfed patches or surface patches may be suitable in certain scenarios, but they do not provide the necessary edge-to-edge overlap and load distribution that a splayed patch offers, especially in thin materials. Meanwhile, a plug patch might not adequately address the problem of a small hole in such thin skins, as it would require more material removal and may not conform well to the surrounding area.