Theme:

Reduction of weight in the manufacture of a kayak with the use of the sandwich material Easy Cell 75 Closed Cell Foam PVC, 3 mm thickness.

We have previously used Soric 3mm in a construction of a kayak with one layer of carbon fiber and one layer of Kevlar, then sorric as sandwich and finally a layer of carbon fiber, all produced in a single resin vacuum process.  A strong construction, but a little too heavy.

To reduce the weight we have now used Easy Cell 75 Closed Cell PVC Foam, 3mm thickness as sandwich.

In the design we have, with the vacuum resin infusion process, performed the outer carbon and Kevlar layers, and after the final curing, glued with resin, a layer of 3m EasyCell75. After this glue has hardened, we have again, with the vacuum resin infusion process, performed the innermost carbon layer on top of the foam.

Unfortunately,the weight is almost the same, and it is apparently a weight gain that occurred during the infusion process in the foam, and the last carbon fiber layer. We know from the past that the carbon layer itself occupies only 50% resin by weight.

Why do we have this weight gain?

Wich methode should we use to reduce weight?