The stringers and bulkheads are glassed in. The surrounding fiberglass that the new glass would bond to was ground and cleaned with acetone. This created a lot of dust and makes one itch. For glass, .75 oz matt was first used, followed with 24 oz roven cloth. 2 layers of mat and woven were used on the stringers, and one layer was used on the bulkheads. this is where it gets really messy, and the fumes will take you to the moon if you are not careful. 3 gallons of resin was used for all of this. mixing the resin and hardner is a hit or miss depending on the temp. I had a few batches gell up within 10 minutes, and others that took over 1 hour. After all the glass work was done, the boat came out of the garage and sat in the sun. These stringers are now strong again.