How to Use a Heat Sealer: Step-by-Step Guide, Safety Tips & Best Practices

October 30, 2025

Industrial Packaging

How to Use a Heat Sealer: Step-by-Step Guide, Safety Tips & Best Practices

Heat sealers are indispensable tools in many industries, including food packaging, pharmaceuticals, manufacturing, and e-commerce.

Whether you’re sealing plastic bags of parts in a warehouse or preserving the freshness of perishable goods in a commercial kitchen, understanding how to use a heat sealer properly can save time, reduce waste, and ensure professional results.

In this article, we’ll walk through when to use a heat sealer, how to operate one step-by-step, and essential safety precautions. We’ll also look at common sealing issues, maintenance tips, and how to choose the right type of sealer for your application.

What Is a Heat Sealer?

A heat sealer is a machine that uses heat and pressure to bond thermoplastic materials together. The most common use is sealing plastic bags or pouches to keep contents secure and protected. Sealers vary widely in size and style, from small tabletop units for occasional use to heavy-duty industrial models used in packaging plants.

There are 6 common types of heat sealers:

Impulse Sealers—only generate heat when the sealing arm is pressed down
Constant Heat Sealers—maintain a steady heat source
Vacuum Sealers—remove air from the package before sealing
Band Sealers—continuous sealers for high-volume operations
Portable and Handheld Sealers—used for fieldwork where portability is key
Tray and Clamshell Sealers—used in foodservice to seal pre-formed trays and hinged plastic packaging, respectively.

Choosing the right heat sealer for your task is essential, as different types are tailored to specific materials, products, and production volumes to ensure strong, reliable seals.

When to Use a Heat Sealer

Heat sealers are used in any situation where airtight, tamper-evident, or protective packaging is required. Here are some common scenarios:

1. Food Packaging:

Extend shelf life of dry goods, frozen foods, or perishable items.
Keep contents fresh and safe from contamination.

2. Retail and E-commerce:

Protect products in transit.
Provide a professional presentation with neatly sealed bags.

3. Pharmaceutical and Medical Packaging:

Ensure sterile conditions for drugs and medical devices.
Provide tamper-evidence for regulatory compliance.

4. Industrial Use:

Seal small parts, components, or powders.
Prevent moisture, dust, and static damage.

If your product or item needs to be protected from moisture, dust, air, or tampering, a heat sealer is likely the right tool for the job.

How to Use a Heat Sealer: Step-by-Step Guide

Using a heat sealer properly is key to producing strong, consistent seals and preventing packaging waste or product contamination.

Here is a more detailed breakdown of how to use a heat sealer in an industrial setting:

Step 1: Choose the Right Packaging Material
Step 2: Prepare and Power On the Machine
Step 3: Fill and Load the Bag
Step 4: Seal the Bag
Step 5: Allow the Seal to Cool
Step 6: Inspect the Seal for Quality
Optional Step: Trim or Label

Step 1: Choose the Right Packaging Material

Before operating your heat sealer, ensure that the packaging material you’re using is compatible with your type of sealer.

Each heat sealer is designed to work with specific materials and thicknesses:

Impulse Sealers work best with polyethylene (PE) and polypropylene (PP) bags, usually up to 6 mil thick.
Constant Heat Sealers are better for multi-layer laminates, foil, or thicker plastic films.
Vacuum Sealers require vacuum-specific bags, usually with embossed channels.

Pro Tip: Check the packaging for a seal icon or material abbreviation. Always test a few samples before beginning a full run.

Step 2: Prepare and Power On the Machine

Make sure your heat sealer is placed on a clean, flat surface.

If it’s a constant heat or band sealer, plug it into a grounded power outlet and allow it to warm up. Impulse sealers require no warm-up time.

Then:

Set the temperature: Use the control dial or digital settings to adjust the heat based on your material. Thicker or multi-layer films require higher temps.
Set the dwell time: This controls how long the sealing jaws stay closed after heat is applied—usually between 0.5 and 2 seconds.
Adjust pressure settings (if available): Some sealers allow you to fine-tune how hard the jaws press together.

Pro Tip: Refer to your sealer’s user manual or the packaging material supplier’s guide for recommended settings.

Step 3: Fill and Load the Bag

Place the product inside the bag, pouch, or sleeve. Avoid overfilling; there should be at least 1 inch (or 25 mm) of empty space above the product to create a secure seal.

When loading into the sealer:

Lay the open end of the bag across the sealing element (or conveyor for band sealers).
Align evenly to avoid crooked seals or uneven pressure.
Ensure no wrinkles or debris are in the sealing area, as these can lead to leaks or weak seals.

Pro Tip: For bulk products like powders or liquids, use a funnel or bag holder to fill the bag, pouch, or sleeve more easily and to prevent spills near the seal zone.

Step 4: Seal the Bag

Once everything is aligned:

For manual impulse or constant heat sealers, press down the handle or sealing arm firmly and hold until the cycle completes. Some models have indicator lights or audible alerts to signal completion.
For foot-operated sealers, step on the pedal to initiate the sealing process. This is ideal for repetitive tasks or large bags.
For band sealers, guide the open end of the bag onto the conveyor, and the machine will automatically seal as it passes through.

Pro Tip: Apply consistent pressure when sealing manually. Inconsistent pressure can create weak spots or leaks in the seal.

Step 5: Allow the Seal to Cool

After sealing, do not immediately tug or handle the bag. Let the seal cool for 1–2 seconds so the plastic can re-harden. This prevents warping or premature seal failure.

For impulse sealers, the cooling period is built into the dwell time setting.
For heavy-gauge or multi-layer films, give a few extra seconds of rest before lifting the bag.

Pro Tip: A cooling tray or small fan can help speed up this step in high-volume operations.

Step 6: Inspect the Seal for Quality

Once the seal has cooled, check the finished seal for visual and physical integrity. A proper seal should be:

Even across the width of the bag
Smooth, with no bubbles, wrinkles, or gaps
Strong when gently pulled (but not torn)

For critical packaging, for items like electronics, pharmaceuticals, or sterile objects, perform a peel test or burst test periodically to ensure the seal strength meets your desired quality standards.

Look for these troubleshooting signs:

If the seal won’t hold — too low heat or too short dwell time
If the seal is brittle or burned — too high heat or too long dwell time
If the seal has pinholes or gaps — contamination on the sealing bar or misalignment

Optional Step: Trim or Label

If your packaging system requires a finished look:

Use a bag trimmer or cutter to remove excess plastic above the seal.
Apply labels for product identification, barcodes, or branding.
Some heat sealers come with built-in date coders or embossers to stamp production info directly onto the seal.

Safety and Maintenance Tips

To keep your heat sealer in top working condition and ensure operator safety, follow these best practices:

SAFETY GUIDELINES	MAINTENANCE TIPS
Keep hands and clothing away from the heating element during operation. Ensure the machine is turned off or unplugged when performing maintenance. Train employees thoroughly before using any high-heat equipment. Turn off or unplug when not in use to prevent overheating and reduce fire risk. Let the machine cool down before cleaning, moving, or performing maintenance.	Regularly clean the sealing bar and replace worn Teflon covers. Inspect wiring and heating elements for damage. Lubricate any moving parts according to manufacturer guidelines. Replace worn-out parts like heating wires, elements, or pressure pads promptly as needed. Store the unit in a dry, dust-free environment when not in use.

Heat sealers are generally safe, but improper use can result in burns, electrical hazards, or damaged materials.

Final Thoughts

Heat sealers are powerful tools that can improve efficiency, enhance product presentation, and extend shelf life. By understanding how and when to use them and following best practices, you’ll get strong, professional seals every time.

Whether you’re packaging small parts in a warehouse or prepping shipments in an e-commerce operation, the right heat sealer makes a big difference. Choosing the proper unit, dialing in settings, and maintaining safety will allow you to seal with confidence.

Need help choosing the right heat sealer for your business? Reach out to Imperial Dade with details about your packaging materials and daily output, and we’ll help you find the perfect fit.