The envelope is the balloon shaped fabric part which holds the air and floats above the basket. Only 2 types of yarn are suitable to make the fabric of hot air balloons: nylon (polyamide) and Dacron (Polyester). Dacron can withstand higher temperatures, but Nylon can be made stronger and lighter. Our Hot air balloon envelopes are made from Nylon.
Woven fabric has a mesh like structure which allows air to be passed through it – a balloon needs to retain the air so the fabric is coated with a material which seals the fabric. Polyurethane is commonly used with hard-wearing minerals added such as silicone or a synthetic rubber called 'neoprene. This coating is applied under pressure by a machine. All coatings contain ultraviolet inhibitors to slow down and delay the degredation caused by sunlight.
Typical balloon fabrics weigh between 1.2oz and 2.4 oz per sqaure yard. These fabrics have tensile strengths of 40 to 100lbs per inch wide strip.
An infinate variety of shapes and designs can be achieved by the designers and manufacturers of hot air balloons.
