Sonntag fins are custom made for each windsurf slalom sailor, racer, or speed sailor placing an order, specifically tailored to the rider’s size, riding style, and the feel and feedback the rider desires. The newest carbon fiber fin, featuring a bright green finish, is built with a bio-based resin epoxy, Sicomin’s GreenPoxy® 33.

Sonntag has partnered with Time Out Composite on fins for years and had great success with Sicomin epoxies but wanted to look into a more sustainable epoxy resin system for the new carbon fiber fin.

Sicomin’s GreenPoxy® 33 resin was the answer. Testing proved this, as the GreenPoxy® 33 test samples allowed for a less brittle fin, making it stronger should it run into a rock.

The Sonntag fins are manufactured in molds using a lay-up of woven, stitched biaxial and heat-set unidirectional carbon fiber fabrics in four steps:

Step 1: Sonntag’s green in-mold coating is applied.