Welding vinyl for banners and signs has several advantages over sewing for the same applications.
Strength
​Heat welding produces a stronger bond than sewing. With the correct application of heat and pressure welds are as strong as the material itself. Conversely, the holes made by the sewing needle weaken the fabric and provide the most likely point of breakage in a final product.
Longevity
​Many sewing threads are not suited for use outside as they deteriorate quickly under the strain of the elements. UV-treated threads tend to be thick and more difficult to work with. Welded seams hold up as well as the rest of the banner or sign.
Appearance
​Sewn seams are more visible than welds, particularly from the front of material. Welds are near invisible improving the finished product’s appearance.
Time
​With heat welding, joining two fabric rolls can be done in a single pass instead of multiple sewing passes required to achieve the same joint.
Ease of use
Large projects are much more suited to heat welding than sewing. Large pieces of material are heavy and awkward to pick up and move through a sewing machine. Automatic welding machines allow material to remain stationary while the machine itself moves.

Read more: Advantages of Welding Industrial Fabrics