A bag sealer is an essential tool in packaging. With many models and options, selection can feel complicated. This guide explains how two popular sealer types work, and helps you determine which sealer is right for you.
Why use a bag sealer?
- Secure: Airtight, tamper-evident closure.
- Freshness: Barrier protection from moisture and contaminants.
- Efficiency: Seal in seconds, increase throughput.
- Professional appearance: Clean, repeatable seals.
- Cost effective: Reduce waste and extend shelf life.
What is a bag sealer and how does it work?
Bag sealers use heat and pressure to close flexible packaging like poly bags, pouches, and laminated films.
- The heating element warms up instantly or continuously.
- The jaws close, the inner layers fuse under heat and pressure.
- A short cooling period creates a strong, airtight, tamper-evident seal.
Answer these questions before you choose
- Volume: How many bags per minute do you need to seal?
- Material: What is the film type and total thickness?
- Dimensions: What is the open-end bag width and length?
- Filled weight: How heavy is the package during sealing?
Impulse vs Direct (Constant) Heat: the key differences
| Feature | Impulse Sealers | Direct / Constant Heat Sealers |
|---|---|---|
| Compatible Materials | Standard poly bags: PE, PP | Thicker or coated films: foil, poly-lined paper, gusseted laminate |
| Warm-up | No warm-up. Heats on activation only. | Requires warm-up. Jaws hold set temperature. |
| Heat Penetration | Shallow, ideal for single or light gauge poly. | Deeper penetration for dense or multi-layer stock. |
| Typical Seal Widths | Round (shrink), 2 mm, 5 mm, 10 mm | 8 mm, 10 mm, 15 mm, 20 mm |
| Energy Use | Power draws only when sealing. | Constant draw to maintain temperature. |
| Limitations | Not ideal for heavy laminates or foil. | Cannot seal straight polyethylene. |
| Learning Curve | Minimal. Light maintenance on consumables. | Simple once set. Requires temperature setup and seal technique. |
Types of impulse heat sealers
- Hand Sealers: Compact and economical for general poly bags.
- Portable sealers: Useful for irregular shapes or spot sealing. You take the sealing jaws to the bag.
- Foot Sealers: Pedal activation keeps both hands on the bag.
- Automatic Sealers: Consistent seals with heat and cool timers. Great for high volume uniform sealing.
Types of constant heat sealers
- Handheld Sealers: Lower volume and irregular seams.
- Foot Sealer: Hands-free control for heavier materials.
- Table Top: Timers for heat and dwell to standardize results.
- Band Sealers: Continuous sealing on a conveyor for higher throughput.
Material to sealer match guide
| Material | Typical Thickness | Recommended Sealer | Notes |
|---|---|---|---|
| PE or PP poly bags | 1–6 mil total | Impulse or band sealers | Most general packaging needs. |
| Laminated pouches | 3–10 mil | Constant heat | Better penetration for multi-layer films. |
| Foil pouches | 3–7 mil | Constant heat | Improved seal quality on foil layers. |
| Poly-lined paper bags | Varies | Constant heat | Consistent temperature gives stronger bonds. |
| Gusseted heavy bags | 6–12 mil | Constant heat or band sealer | Consider band sealer for speed and uniformity. |
Sizing and throughput tips
- Select a sealing width at least 0.5 in wider than the bag opening to improve alignment.
- Match cycle time to your target bags per minute. Automatic or band sealers help maintain pace and are good for higher volume operations.
- For heavier filled weights, prefer foot or band sealers to keep product stable during sealing.
Common mistakes to avoid
- Using impulse sealers on heavy laminates or foil.
- Using constant heat on thin poly bags.
- Under-sizing the sealer bar relative to the bag width.
- Skipping cool time, which can stretch or break the seal.
- Neglecting routine consumables such as Teflon covers and elements.
FAQ
Can a constant heat sealer seal polyethylene?
No. Constant heat sealers are for thicker or coated materials such as foil and laminated films. Use impulse for PE and PP.
What seal width should I choose?
Choose a seal width that covers the bag opening with safe margin. Wider seals look more professional and can improve strength.
When should I upgrade to a band sealer?
Move to a band sealer when you need continuous, high-volume throughput, consistent seals across many SKUs, or heavier materials that benefit from controlled heat and dwell in motion.
Next step: Need help matching a sealer to your film and throughput goals? Contact us for a fast recommendation, or browse our heat sealer collection and band sealers.
