We reveal how to seal

Sealing your bag: just press it together and you’re ready? Sure, as long as you take into account the temperature, pressure and time! Here’s everything you need to know:

Where do you apply your seal?

First of all, it is important to know where to seal your bag. Seals are applied to the top of the bag. You must pay particular attention to keeping 7.5 mm to 10 mm from the top of the bag. It is not a good idea to seal the entire edge because the glue/film ratio is not optimal there for a seal.

1. Temperature

To get a good seal you need around 90° between the layers. Taking into account heat loss, a sealing temperature of 130° to 140° is usually more than sufficient. If you set the temperature higher then you run the risk of:

  • the paper catching fire
  • the ink becoming dark or black
  • the adhesive holding the paper and film together being activated causing them to separate
  • the film melting and shriveling causing the paper to disintegrate.

So be careful when setting the temperature!

Tip

Check that the temperature set has definitely been reached and that the element of your device is working properly and heating up fast enough. Over time, elements may become slower and give off less heat, which you should take into account.

2. Pressure

In order to get a good seal you also need a certain pressure on the layers. If there is no or not enough pressure, then naturally no seal will be created.

Increasing the pressure accelerates heat transfer and allows you to seal for a shorter time at a lower temperature.

Advanced devices can increase the pressure using compressed air and give the best results. With most heat sealing devices, the pressure can only be adjusted mechanically.

Tip

Try pulling your bag out from between the seal bolts when they are closed. If you can move your bag, then you know that there is no or not enough pressure on the layers to be sealed.

3. Time

You need a certain amount of time to:

  • get through the paper
  • heat the film to the right temperature

Sealing for too short a time can result in the needed temperature between the layers not being reached. This causes inadequate binding between the layers.

Conversely, sealing for too long can damage the packaging, particularly if the temperature is set too high.

 

In short, the message for a perfectly sealed bag is: set the correct temperature, apply enough pressure, seal for just long enough and check your device from time to time!

Do you have specific questions about sealing? D.S.E. Soret is a connoisseur of his trade and a supplier of sealing machines that we can recommend https://dse-soret.com/en/