Shrink tunnels
A shrink tunnel shrinks sealed packages tight. Heat gun vs. hood vs. tunnel, combo units, sizing, power needs, settings, and prices from $2,539.
What a shrink tunnel does
A shrink tunnel is a heated chamber with a conveyor running through it. Sealed packages ride through, and hot air flows around them. The film shrinks tight around the product. An L-bar sealer only makes a loose sealed bag around the product. The tunnel is the second step that shrinks it. Eastey sells the two as separate machines and as combo units on one frame. Some products only need the loose sealed bag. Those need no shrink step.
First decide what the finished package should look like. Then choose the heat source that makes it at your volume.
Heat gun, hooded chamber, or conveyor tunnel
| Heat source | How it works | Best for | Example |
|---|---|---|---|
| Heat gun | The operator aims a handheld gun at the sealed bag. | Low volume and occasional use. Cheapest option, but results depend on the operator. | Most shrink heat guns run on 110 V at about 1,200 W. |
| Hooded chamber | The L-bar seal and the shrink happen under one hinged hood. The operator loads, closes, and waits. | Small packages at a few per minute in a small space. | Sealer Sales SS-48ST: 12 × 18.5 in. seal, 6 in. max height, 3 to 5 packs per minute. |
| Conveyor tunnel | A conveyor carries the pack through a heated chamber with recirculating air. | Consistent looks and nonstop output. Pairs with semi-automatic and automatic sealers. | Uline H-951: 16 × 6 in. opening, 0 to 85 ft per minute mechanical conveyor range, 110 V. Uline warns the top speed is too fast to shrink film. |
| Bundling tunnel | A larger tunnel with bigger heaters and cooling fans for heavy polyethylene. | Multipacks and bundles, usually with a sleeve wrapper rather than an L-bar. | Eastey bundling tunnels. |
Separate machines or a combo unit
A combo unit puts the L-bar sealer and the tunnel on one frame. You buy it as one system with a set transfer between the two stages. Heat Seal’s HSE-100 and the Clamco 250C are examples. A combo is not always smaller than two separate machines. Compare the real layout drawings.
Separate machines let you pick each one for its own job. You can also upgrade one stage later if the other machine still fits with it. But you or the supplier must match conveyor heights, belt widths, and speeds. Ask for a layout drawing that shows both machines and the transfer between them.
| Decision | Combo system | Separate sealer and tunnel |
|---|---|---|
| Buying | One defined package. Check which options are included. | Separate model numbers, interfaces, and responsibilities. |
| Layout | The shared frame fixes much of the layout. | More choice of direction, spacing, and conveyor layout. |
| Package transfer | Designed as a pair. Still test your smallest product. | Check conveyor height, gap, support, and speed together. |
| Future changes | Replacing one stage may be harder. | You can upgrade one stage if the other machine is compatible. |
| Power | Check the rating for the whole unit. | Check each machine and your building’s total load. |
The table below compares four combos. Specs were checked October 1, 2026. All sizes are in inches. Tunnel openings and inside sizes are labeled apart because they are not the same thing. Neither one is a guaranteed maximum package size.
| Model and source | Seal area | Film capacity | Tunnel dimensions | Electrical |
|---|---|---|---|---|
| Heat Seal HSE-100 manual | 16 wide × 20 long | 17 wide | Inside: 14 wide × 6.5 high × 20 long | 115 V, single-phase, 17 A. Manual calls for a dedicated 20 A circuit. |
| Clamco 250C | 17 end × 23 side | 20 centerfold | Opening: 16 wide × 9 high. Inside length 22. | 220 V, single-phase, 50 A |
| Clamco 4C | 18.5 end × 21.5 side | 24 wide, 12 roll diameter | Standard opening: 15.5 wide × 9 high. Inside length 26.5. | 220 V, three-phase, 22 A |
| Clamco 6C | 27.5 end × 33 side | 32 wide, 12 roll diameter | Standard opening: 25.5 wide × 13.5 high. Inside length 34. | 220 V, three-phase, 35 A |
The 250C closes its seal arm with a motor. The 4C and 6C list automatic closing as an option. Check which setup each quote includes. These models were picked because their documents are public. This is not a ranking or a full market survey.
Size the tunnel to the package
Opening. The wrapped package must pass through without touching the top or sides. It also needs room for the loose film before it shrinks. So check the loose film bag against the opening, not just the bare product. Uline rates its 16 × 6 in. tunnel opening for packages up to 15 × 5 in. That is 1 in. less than the opening in width and in height, in total. It does not set a ½-inch clearance below a product resting on the conveyor. It is not a rule for other tunnels either. Film that touches the tunnel walls can burn.
Test the whole path. Keep the product facing the same way through the whole trial. Ask the supplier to confirm working clearance, conveyor support, package stability, and the airflow needed. Watch your smallest item cross from the sealer to the tunnel. Watch your tallest or least stable item leave it. After cooling, compare the finish on the top, bottom, corners, and seal. A big tunnel alone does not prove enough output for your film and package. For a sizing request with real numbers, see the buying guide.
Match the tunnel to the sealer
Time in the heat. Dwell time is how long the package spends in the heat. It equals the heated chamber length divided by belt speed. With the chamber in inches and the belt in feet per minute:
dwell in seconds = chamber length (in.) × 5 ÷ belt speed (ft/min)
The Sealer Sales CN-4520A has a 31.5 in. chamber and a 0 to 20 ft/min conveyor. At 10 ft/min a package spends 31.5 × 5 ÷ 10 = about 16 seconds in the heat. At 20 ft/min it spends about 8 seconds. A longer chamber gives the same time at a faster belt. To find the right setting, Uline’s manual says to raise temperature and slow the conveyor in small steps until the film shrinks. Clysar’s target is a bag that balloons in the main body of the tunnel. It should collapse about ¾ of the way through. The last quarter is for cleanup.
Belt speed for your output. The tunnel belt must carry packages away at least as fast as the sealer makes them. It also needs a gap between each one. The minimum belt speed is:
belt speed (ft/min) = packs per minute × (package length + gap, in inches) ÷ 12
Say you run 10 packs per minute of a 12 in. package with a 6 in. gap. That needs 10 × 18 ÷ 12 = 15 ft/min. On the CN-4520A that leaves 31.5 × 5 ÷ 15 = about 10.5 seconds of heat. If the film needs more heat time, you have options. Use a longer chamber, run fewer packs per minute, or make heat and airflow changes the supplier approves. A hotter setting may damage the product, so it is not an automatic fix. Ask the supplier what gap their tunnel needs between packages. If the sealer makes 20 packs per minute and the tunnel can only shrink 10 well, the tunnel sets your output.
Air speed and direction. Clysar says its films prefer high air velocity. But too much air speed causes whitened film and burn holes. So does air aimed the wrong way, or clogged intake screens. One of Clysar’s fixes for dog ears is to aim more air at the package ends. Dog ears are the loose film points left at the corners. Tunnels differ in how much air control they give you:
- The Clamco 4T and 6T have variable air velocity and adjustable dampers. Air speed and where the air goes are separate controls.
- Arpac’s mesh belt tunnels have baffles that control air volume from the top, sides, and bottom.
- Eastey’s Professional Series has airflow from four directions, variable airflow, and plugs for patterned airflow.
Conveyor type. The conveyor decides how the bottom of the package shrinks. It also decides whether the bottom gets marked.
| Conveyor | What makers say |
|---|---|
| Live roller or rod | YPS says roller conveyors give maximum airflow to the underside. They keep the pack out of constant contact with a belt, which prevents marking. Eastey says live rollers give a more finished look for retail packages. PAC offers 1 in. roller spacing instead of 1.5 in. for smaller products. |
| Mesh belt | PAC uses a mesh belt in place of rollers for smaller and lighter products. Arpac says its PTFE-coated fiberglass mesh lets hot air reach all surfaces of the package. YPS recommends a steel mesh belt for polyethylene because it gives pack stability. |
Run your smallest, lightest, and least stable product on the conveyor you are quoted.
Cooling. PAC offers external cooling fans at the tunnel exit. They finish the shrink and cool the product. PAC also offers an exit conveyor that gives time for a full shrink. Clysar suggests a fan at the pack-out station so warm packages can go into cartons sooner. Many tunnels list “automatic cool down.” That is a different feature. It protects the tunnel, not the package. PAC says it “extends the life of the heating element”.
Electrical requirements
Tunnels draw far more power than sealers. Check your building’s electrical service before you choose one.
| Equipment | Electrical requirement |
|---|---|
| Uline H-951 tunnel | 110 V, 2,200 W, 3-prong plug. The simple math is 2,200 W ÷ 110 V = 20 A. Install to the nameplate and the maker’s circuit rules, not this math alone. |
| Uline H-4018 tunnel | 120 V, “20-amp service is required” |
| Uline H-2034 tunnel | 220 V, 20 A, 2,100 W |
| Clamco 250C combo | 220 V single-phase, 50 A, 6,000 W tunnel |
| Eastey ET20 to ET36 tunnels | 220 V three-phase, 50 to 60 A |
| Eastey ET48 to ET70 tunnels | 220 V three-phase, 80 to 110 A |
Some small tunnels run on 110 to 120 V and need their own 20 A circuit. Confirm the exact model. Mid-size tunnels move to 220 V. Larger tunnels often run on 220 V three-phase at 50 A and up. Eastey offers some models in 220 V single-phase or 480 V three-phase. Order the voltage your plant supplies. Have an electrician confirm the outlet, circuit, and panel.
Starting settings by film
These are published starting points for specific machines. They are not settings for every machine. Use the manual for your equipment.
| Film | Eastey seal bar temperature | Eastey seal pad | Uline tunnel starting temperature |
|---|---|---|---|
| PVC | 325°F, about 1 second dwell | Felt | 275°F |
| Polyolefin | 335°F, about 1 second dwell | Sponge rubber | 325°F |
| Polyethylene | 360°F, about 1.5 seconds dwell | Sponge rubber | 325°F (bundling film) |
The seal settings are for the mushroom insert in Appendix B of the Eastey EM Professional Series manual. The tunnel settings are from the Uline H-4018 manual. The H-4018 troubleshooting guide calls for a 30-minute warm-up and no drafts. Follow the warm-up steps for your own tunnel. Don’t apply that time to every model.
Keep the bag loose
A bag pulled tight around the product before the tunnel is more likely to have weak seals. Those seals can blow out during shrinking. Eastey’s manual says to leave the bag loose.
The bag also needs a way for air to escape. Eastey’s manual says “perforation is required to allow air to vacate when the product passes through the shrink tunnel”. You can order pre-perforated film or have a machine perforator installed. Clysar notes that worn perforating rolls are a leading cause of rejects. Too little venting shows up as severe ballooning or burst bags. It also causes seals that blow out in the tunnel. The shrink film guide covers hole patterns.
Shrink tunnel prices
New standalone conveyor tunnels listed on October 1, 2026, from $2,539 to $15,827. The low end is the 110 V US Packaging & Wrapping 1606-20. The high end is its 72 in. TL-1812-72. Small 110 V tunnels such as the Uline H-951 list at $3,000. Its 220 V H-2034 lists at $4,195. Larger tunnels from US Packaging & Wrapping run from about $5,400 to $15,800, based on opening and chamber length.
Sealer and tunnel combo units run $7,999 to $25,365. The dated combo listings are in L-bar sealer prices. Compare a combo quote with the total for a separate sealer, tunnel, transfer equipment, and installation. Don’t compare it with a sealer-only price. For each quote, record the exact model and voltage and the powered closing option. Also record the discharge conveyor, freight, installation, training, and spare parts budget.
Used asking prices vary. Some are even higher than a current new price. Compare condition and installed cost. See shrink wrap machine cost and used machines.
Questions for the supplier
- Can the tunnel opening take my tallest and widest package in its travel direction, with room for loose film?
- Will the tunnel keep up with the sealer at my target output?
- Do conveyor heights and belt widths work for my smallest and least stable product?
- What happens to a package in the tunnel if the line stops?
- What electrical service, ventilation, and clearance does the whole system need?
- Can I see my product and film run through the complete system before I buy?
- Who is responsible if the sealer meets its rate but the tunnel can’t make good finished packages at that rate?
Put a finished-package acceptance test in the purchase agreement. For problems with the finished pack, see troubleshooting.
Common questions
A heated chamber with a conveyor. Sealed packages ride through it. Hot air flows around them, and the shrink film tightens around the product. It is the second step after an L-bar sealer or side sealer seals the film.
New standalone conveyor tunnels listed from $2,539 to $15,827 on October 1, 2026. Small 110 V tunnels start around $2,500 to $3,000. Sealer and tunnel combos run $7,999 to $25,365. See all prices.
Uline's tunnel manual suggests starting at 325°F for polyolefin and 275°F for PVC. Then adjust temperature and conveyor speed in small steps. Your tunnel's manual and film data sheet override these starting points.
Yes, for low volume. A heat gun costs far less, but it is slow and results depend on the operator. A tunnel gives consistent results at production speed. Compare heat guns.