Heat sealing vinyl-coated fabric

Compiled by Juli Case

We’re looking into making truck covers and know that we will be heat sealing the seams. What is the recommended temperature range for heat sealing vinyl-coated fabric?

The range of temperatures used to heat seal vinyl fabric is so wide that it isn’t something that you are likely to find useful. Vinyl-coated fabrics can begin to soften at about 250 degrees (F), but there are some heat-sealing machines that can safely weld the material at temperatures of up to 1350 degrees (F). Why such a difference? It’s due to the number of variables involved, both in the fabric and in the equipment. For example, the particular “recipe” of vinyl used in your specific fabric, whether it has UV stabilizers, or even the color of the material, can affect at what temperature it begins to soften. And that’s just talking about the vinyl itself; the base material (nylon versus polyester, for example) and the weight of the fabric also need to be considered.

As for machines, the type of welder used, the speed at which the machine works and the dwell time the operator chooses all can be factors. That’s how a fast-moving piece of welding equipment can successfully weld vinyl-coated fabric at the relatively high temperature of 1350 degrees (F)—the fabric passes through so quickly that it is sealed without being damaged.

So how are you supposed to find the right temperature for the material you’re using? You’ll need to get some input from your suppliers, most notably, your equipment supplier. Several of the equipment companies we spoke to said they routinely receive fabric samples from the customers, which they will sample weld and send back with the information on how they’d set the equipment up and achieved a successful weld.