A model of a pond – Plastic shells for small and medium-sized ponds can be purchased in many supermarkets. Such a shell can be made independently from a resin-glass laminate. However, you will need a model, on which the glass mat will be placed. Such a model is easiest to make of clay or construction plaster, formed on a flat slab or even ground. We shape the shape in wet clay, while we sculpt in solidified plaster. This form is easy to correct if necessary.