What is the typical scarf radius recommended for repairing single skin?

The typical scarf radius recommended for repairing single skin is 12:1. This ratio signifies that for every unit of thickness of the laminate, you should have a scarf joint tapering back twelve units.

A scarf joint is an essential aspect of composite repairs, as it allows for a smoother transition between the old and new material, thus distributing loads more evenly and reducing stress concentrations in the bonded area. Using a scarf radius of 12:1 helps to create a strong and durable repair that can withstand the forces typically encountered in environments where single-skin composites are used, such as in marine applications.

Using a scarf radius that is too short, like 6:1 or 8:1, may not provide sufficient surface area for adhesion and can lead to a less effective joint, increasing the risk of delamination or failure. Similarly, while a 15:1 ratio could theoretically provide a very gradual transition, it might be unnecessarily complicated for most repairs and could require excessive amounts of material and labor without significant benefits.