Dog Waste Bag Seal Types: Flat Seal, Side Seal and Gusset
How the three common bag constructions differ, where seals fail in use, and what to write into a specification to avoid field failures.
Most field failures in dog waste bags start at a seam rather than in the middle of the film. The construction of that seam depends on how the bag is made. This guide explains the three common constructions, where each one fails, and what to specify.
Flat seal
A flat seal joins two layers of film across the full width at the bottom of the bag. It is simple, runs quickly and suits roll bags. The seal width and the temperature profile matter: a narrow or cold seal will peel before the film tears.
Side seal
A side seal is made on a tube of film, with the seam running along one side. It can be strong and consistent, and it suits formats where the bag is loaded from the top. The side seam is the weak point, especially when the bag is pulled sideways in a dispenser.
Gusset seal
A gusset adds a fold at the bottom or the sides, giving the bag more volume. It uses more material and more seal lines, so there are more places for a failure. Gusseted bags suit larger formats and heavier loads.
Where seals fail in use
Four causes cover most failures: a seal that is too narrow for the film, a cold or contaminated seal line, a perforation that is too deep next to the seal, and a dispenser that pulls the bag at an angle the seam cannot take. Testing the bag in the actual dispenser catches the last one before production.
What to specify
Write down the construction, the seal width, the film gauge and the seal test method. Ask the supplier to record first-article seal strength and to check it during production. A specification that names the test is easier to enforce than one that says strong seal.
Related pages
See strength and leak testing for strength and leak testing, the thickness guide for the thickness guide, and durable PE dog poop bags for a durable PE option.
