How a pedal bag sealer works

The bag is placed on the shelf in front of the jaws. The operator flattens the bag mouth across the bar, then presses the foot pedal. This action closes the jaws on the bag; for impulse models, it also starts the heating cycle.

Heat and pressure bond the two layers of film, and the seal sets as it cools. Using a foot pedal bag sealer keeps both hands free to hold the bag straight and flat.

First, fill the bag with your product. Next, lay the mouth of the bag flat across the bar with both hands, ensuring there are no creases. Press the foot pedal to close the jaws. On the constant heat model, keep the pedal pressed for the sealing time. On the impulse models, hold the pedal until the indicator light switches off and wait one to two seconds longer, then release the pedal and remove the bag; the seal will reach full strength as it cools.

It is essential to leave enough empty film above the contents of the bag. This extra space allows the mouth to lie flat across the bar without product entering the sealing area. If the contents are too close to the seal, they may become trapped, weakening the seal and causing leaks. For instance, when sealing a bag of powder, ensure the powder is well below the mouth before sealing.

The shelf in front of the jaws supports the filled bag during sealing, so the weight does not strain the seal while it is still warm. Always hold the bag mouth taut with both hands as the jaws close. Any fold or crease in the mouth can create a weak spot where the bag might open later.

Impulse sealer or constant heat: operating principles

The ZONE300D is a constant heat sealer. The bar remains at the set temperature, ready for each bag. This model is suitable for sealing thick bags and aluminium-laminated (foil) bags. The seal is 300 mm long and 14 mm wide, and the temperature can be set from 0 to 300 °C.

The ZONE450F and ZONE600F are impulse sealers. A wire in the bar heats only when the jaws are closed, then cools under pressure. The seal sets before the bag is released. Both models seal PE and PP film as well as multi-layer film. The ZONE600F can seal wide bags up to 600 mm in a single operation. If you require a foil bag sealer, select the ZONE300D.

The ZONE300D produces a 14 mm wide seal, which is wider than the 2–5 mm seal made by the ZONE450F and ZONE600F. A wider seal is beneficial for heavy or bulky items, as it provides more area to support the load. For example, a heavy bag of granules up to 300 mm wide can be sealed on the ZONE300D, where the 14 mm seal carries the weight. The impulse models, with their narrower seals, are ideal for standard PE and PP bags.

The ZONE300D keeps its bar hot continuously while switched on, so it is ready to seal as soon as the pedal is pressed. The impulse models only use heating power during the brief pulse when the jaws are closed, so they consume no heating energy between bags.

With a constant heat bar, it is important to keep hands away from the sealing area, as the bar remains hot even when not in use. Always switch the machine off during longer breaks to prevent accidental burns and save energy. After turning the ZONE300D on, wait until the bar reaches the set temperature before sealing the first bag.

An impulse bar is cool between seals, reducing the risk of accidental burns during setup or bag placement. The seal cools under pressure before the jaws open, resulting in a flat and tidy finish on thin film. This process adds one to two seconds per bag, but ensures the seal is set before the bag is moved. In summary, foil laminates and thick bags up to 300 mm wide are sealed with the ZONE300D; standard PE and PP bags are suited to the ZONE450F or ZONE600F, which also accommodate bags wider than 300 mm.

ZONE300D, ZONE450F and ZONE600F: comparison chart

The table below compares the ZONE300D, ZONE450F and ZONE600F heat sealers by seal length, heating method, compatible films and main settings.

To use the comparison chart, start with the film row: if you need to seal foil bags, only the ZONE300D is suitable. Next, compare the seal length to your widest bag mouth, then the seal width, which is greater on the constant heat model. Finally, check the supply row, as the ZONE300D operates on 220 V only, while the impulse models can run on either 110 V or 220 V.

Which bags each bag sealer closes, by model

The ZONE300D is designed to seal PE and PS film as well as multi-layer laminates, including aluminium-laminated bags. The ZONE450F and ZONE600F are suitable for sealing PE and PP film and other multi-layer films. The available seal lengths are 300 mm, 450 mm or 600 mm, depending on the chosen model.

A poly bag sealer must be able to cover the entire width of the bag opening in a single operation. The ZONE600F is capable of sealing sacks, liners and covers up to 600 mm wide.

Foil laminates are used when it is important to protect the contents from light and moisture. These types of bags are sealed using the ZONE300D, which is suitable for aluminium-laminated and other multi-layer laminates. To ensure a foil bag is moisture-proof, the seal must be complete across the whole opening, so always inspect each seal visually.

Bags with side gussets have four layers of film at the folds, which makes sealing more challenging. The gussets should be folded evenly, and these bags generally require either more heat or a longer sealing time than a flat bag made from the same film, as the seal must penetrate four layers at the gussets. For example, when sealing a gusseted liner, ensure the folds are flat and increase the setting if the seal at the gusset is weaker than elsewhere.

Thicker film requires either a higher temperature or a longer sealing time to achieve a proper seal. For thick bags, use the constant heat model, as its bar remains hot and can provide the necessary heat for a secure seal.

When sealing a bag with a zipper, always seal above the zipper, never across it, as the zipper itself does not seal and prevents the mouth from lying flat.

Settings and operation: impulse sealer and constant heat

With the constant heat model, begin with a low temperature and increase it gradually until the seal is secure. The sealing time is determined by how long the pedal is pressed. For impulse heat sealers, start with a short heating time and increase it by tenths of a second until the seal is effective.

Lay the bag opening flat across the bar, ensuring there are no folds. For impulse models, wait one to two seconds after the indicator light goes out, then pull the bag away sideways, not forwards: the seal will have set but may still be warm, and pulling forwards could break it.

To determine the correct setting for a new bag, use an actual sample. Start with a low temperature or short heating time, seal the bag, allow it to cool, then pull the two sides apart. If the seal peels open, increase the setting slightly and try again. The correct setting is reached when the film tears beside the seal rather than the seal itself opening.

If the setting is too high, you may notice the film shrinking away from the bar, becoming thin or burnt through, or sticking to the PTFE cloth. If the setting is too low, the seal will peel open with little effort. Always check the setting when you receive a new batch of bags, as film thickness can vary. After sealing many bags in succession, the jaws of an impulse sealer may become warmer, so a heating time that was correct at the start may become too long; check the seal occasionally during extended use.

It is helpful to record the correct setting for each bag type on a card and keep it at the machine, so the next operator does not have to start from scratch. With the constant heat model, use the same timing for every bag to ensure each seal receives the same amount of heat.

Pedal heat sealer or band sealer: which is suitable

A pedal heat sealer seals one bag at a time using heat and pressure, making it ideal for packing stations where bags are filled and sealed manually. A band sealer transports bags between belts and seals them continuously, which is suitable for lines processing many bags per hour.

The three heat sealers in this category are pedal-operated models for sealing bags by hand: as industrial heat sealers at a packing station, each one seals a bag up to the length of its bar in a single operation.

With a pedal sealer, the operator sets the pace. Most of the time is spent filling the bag and positioning it flat on the bar, while the actual sealing step takes only a few seconds. If filling and preparing the bag takes longer than sealing, upgrading to a faster machine will not increase the packing station’s speed. A pedal sealer can also handle bags of various sizes in succession without adjustment, whereas a band sealer is set up for a single bag size and is intended for a steady flow of identical bags.

Band sealers are available in vertical versions for upright filled bags and horizontal versions for flat bags. Many band sealers can also print a date or code onto the seal during the process.

A vacuum packing machine removes air from the bag, making it the preferred option for products that must be protected from air exposure; a pedal model seals the bag with air inside. The pedal models in this category are mounted on their own columns, with a shelf for the bag and a foot pedal, allowing both hands to position the bag. This arrangement is especially suitable for longer bars and heavier bags, compared to a small sealer placed on a table.

Which materials can be sealed with heat

A heat sealer bonds two layers of thermoplastic film, such as PE or PP, using heat and pressure. Laminates can be sealed if their inner layer is a sealable film, including foil laminates; aluminium-laminated bags are sealed using a constant heat sealer.

Paper or cardboard on their own cannot be sealed. For printed or laminated bags, it is the inner layer that matters, not the outer surface: a bag with printing on the outside will seal according to its inner film.

Generally, both layers must be made of the same plastic: PE seals to PE and PP to PP, but PE will not seal to PP.

Ask your bag supplier for the material and thickness of the bag, and check whether the inner layer is sealable. This information determines which model and settings are required. For instance, if the supplier confirms a thin PE film, the impulse models are suitable, with the heating time set according to the film thickness; a thick PE bag is best sealed with the constant heat model.

A paper bag with a PE lining seals in the same way as PE: the heat passes through the paper and the two PE linings fuse together inside the seal, so more heat or time is needed compared to a PE bag. The ZONE300D can also seal PS film, while the impulse models are designed for PE, PP and multi-layer films.

What ensures a seal holds on a bag

A seal is secure when the heat, pressure and time are appropriate for the film. The temperature or heating time is set on the machine according to the bag material and thickness, and adjusted until the seal is strong without burning or shrinking the film.

The bag opening must be clean, dry and flat across the bar. Folds or powder in the sealing area will weaken the seal. A wide seal supports heavier contents and gives an even appearance. A narrow impulse seal is energy-efficient, as the bar heats only during sealing.

The necessary pressure for a good seal is provided by the pedal and the top pressure pad. If seals begin to fail at a particular point along the bar, check the pad and PTFE cloth at that location first: a damaged pad causes uneven pressure, and a worn cloth can make the film stick and heat unevenly.

A good seal is clear and even, with no wrinkles, bubbles or burnt areas. To keep the sealing area clean while filling, fold the top of the bag outwards like a cuff or use a funnel, so powder or liquid does not touch the inside of the opening where the seal will be made. For liquids, keep the bag upright so the liquid stays away from the opening until the seal has cooled. A good seal is consistent along its entire length; a weak spot at one end often means the bag was not placed straight.

The seal gains its full strength as it cools, so avoid pulling on the bag or placing any load on the seal while it is still warm. For heavy items, applying two seals, one above the other, provides extra security; the second seal should be placed just above the first, on a clean, flat section of film.

Factors affecting the price of a bag sealer

The price of a bag sealer is mainly determined by the heating method, the type of temperature or time control, and the construction of the frame and jaws, rather than the length of the sealing bar.

The current price for each heat sealer is displayed on its product card above, and all three models include a 12-month warranty. To request a quote, use the Get offer button on the product card; the Add to inquiry button allows you to collect several products in one request.

Running costs are low: they include the PTFE cloth, the heating wire on impulse models, and the top pressure pad. Keeping a spare set of these parts at the packing station helps prevent unplanned downtime.

The ZONE300D maintains a constant bar temperature with two 175 W elements, so it is always ready to use. The impulse models, ZONE450F and ZONE600F, draw 800 W or 1000 W, but only during each brief heating cycle. If you seal bags at intervals rather than continuously, the impulse models will use less energy over a shift.

Choosing the correct sealing bar length

The sealing bar should be at least as long as the width of the bag mouth. If the bar is too short, you will need two presses, which can leave a weak spot where the seals overlap. The entire mouth of the bag must lie flat across the bar in a single press.

To select the right bar length, measure the bag mouth while it is flat and compare it to the bar length: the ZONE450F can seal bags up to 450 mm wide, but a bag that matches the bar length exactly is difficult to position straight. If your widest bag is close to the bar length, choosing the next size up will make sealing easier and help avoid weak spots at the ends.

For bags with side gussets, fold the gussets in before measuring the width. A longer bar can also seal smaller bags: you can seal two or three small bags side by side in one press, provided their mouths are flat and do not overlap. The ZONE300D, ZONE450F and ZONE600F offer bar lengths of 300 mm, 450 mm and 600 mm respectively.

What to check before ordering a heat sealer

Check the widest bag mouth you need to seal, the type and thickness of the film, and whether the bag is a foil laminate. Count how many bags you seal per hour, measure the available space at your packing station, and ensure there is a single-phase socket with a separate earth. Also consider whether the bags contain powder, liquids or heavy goods, as this affects how the mouth is kept clean and whether a double seal is necessary.

The comparison table above will help you identify which of the three models suits your needs: foil bags up to 300 mm wide are best handled by the constant heat model, while wider sacks require the longest bar.

It is also advisable to ask your bag supplier for a few sample bags, so you can set up the machine with real bags on the first day.

If sealing becomes the slowest part of your packing process and the number of bags per hour continues to rise, a band sealer that moves bags through without stopping may be more suitable than a pedal-operated sealer.

Plan the space around the machine. The footprint ranges from 345 × 480 mm for the ZONE300D to 700 × 570 mm for the ZONE600F. Allow extra space for the operator and for tables to hold filled and empty bags on either side. Heavy bags should have a place to rest immediately after sealing, close to the machine, so the seal is not stressed while still warm.

Maintenance and wear parts for your heat sealer

Never close the jaws without a bag: this will burn the PTFE cloth. The PTFE cloth and heating wire (on impulse models) are wear parts. Replace the top pressure pad if the seal becomes uneven.

Keep the bar and PTFE cloth clean and dry. Never use wet cleaning methods or scrape off hardened film with hard objects. All models operate from a single-phase socket with a separate earth. No compressed air is required.

The PTFE cloth covers the sealing bar and prevents the film from sticking during sealing. If the cloth is burnt, torn or has film stuck to it, the seal will become uneven and the film may start to adhere to the bar. In this case, replace the cloth to restore a clean, even seal. For example, if you find the bag difficult to remove or the seal appears rough, check the PTFE cloth first.

A heating wire that has burnt through will not seal the bag at all, so keep a spare wire and cloth available for the impulse models. Always clean the bar when it is cold, using a dry, soft cloth to remove any film residue. Switch off and unplug the machine before changing any wear parts, to ensure safety and prevent electric shock.

Frequently asked questions about heat sealers

Can these heat sealers seal foil or aluminium bags?

Yes, the ZONE300D can: as a constant heat sealer, it seals aluminium-laminated (foil) bags up to 300 mm wide and multi-layer laminates. The impulse models are designed for PE, PP and multi-layer film.

What is the maximum bag width these machines can seal?

The ZONE600F impulse heat sealer can seal bags with a mouth up to 600 mm wide in a single press. The ZONE450F seals up to 450 mm, and the ZONE300D up to 300 mm.

What power supply do these heat sealers require?

All three heat sealers operate from a standard single-phase socket with a separate earth. The ZONE450F and ZONE600F can use either 110 V or 220 V, while the ZONE300D uses 220 V.

Do these heat sealers require compressed air?

No, none of these heat sealers require compressed air. They are pedal-operated and need only a single-phase electrical supply.