Welding tensile fabric
The complex shapes created by modern tensile fabric structures are made up of tens or even hundreds of panels which need to be fixed to one another. Architectural fabrics, which are bought in on the roll, require cutting and joining to ensure strength, durability and water tightness as well as to create the desired aesthetic. The joining of tensile fabric membranes can be done in a number of ways but most commonly by welding.
Fabric welding generally consists of heating the thermo-plastic element in the coating of the fabric using electromagnetic waves in order to soften them and bond the two layers of fabric together. However, as a general rule, synthetic fabrics can be welded, regardless of whether they are coated or note. These materials include:
- Nylon or Polyamide
There are however, many materials that can’t be welded together, for example acrylic fibres, aramid fibres such as Kevlar, Nomex, polytetrafluoroethylene (PTFE) and natural fibres such as cotton, wool and other natural fibres - as they don’t melt!
If a fabric is coated with a protective layer, it is the fabric coating which is to bond the layers together. These coatings include;
- Polyurethane (PU)
- Poly vinyl chloride (PVC)
When welding fabrics is it generally accepted that it is that only like to like polymer combinations can be welded, i.e. polyester to polyester but not polyester to polypropylene. This is just a rule of thumb, however, and doesn’t apply in all cases – Polyamide and Polyurethane are very welded to one another very successfully!