How to shrink wrap

Shrink wrap with a sealer and heat gun or shrink bags, set up an L-bar for each product, and wrap gift baskets, soap, candles, books, and bottles.

Updated October 2, 2026

Pick a method

With a sealer and heat gun

This is the standard small-business method. Uline’s I-bar kits are rated at 1 to 2 packages per minute. A tabletop L-bar sealer needs fewer sealing strokes. Your real output still depends on loading, shrinking, and handling.

1. Pick the film width. Add the product’s width and height, add 2 inches (Uline’s rule), and round up. For an 8 in. wide, 3.5 in. tall box, that gives a 14-inch first guess. Confirm it in a trial. For round items, Uline uses diameter × 3.14 × 1.1 ÷ 2. See sizing centerfold film.
2. Load the film. Put the roll on the sealer’s holder and pull the film over the table. Centerfold film is folded in half along its length, so the fold is already one closed edge. If the layers stick together, Uline’s manual suggests sticking tape to the top and bottom layers and pulling them apart.
3. Place the product between the layers, close to the fold.
4. Seal the open sides. On a fresh roll, follow the machine manual to make the first end seal. After that, each L-bar cycle seals the side and the trailing end. The cut leaves an end seal for the next bag. With an I-bar, you seal each side in a separate step and move the package between steps. Use your model’s settings for a repeatable seal. Too much heat or dwell (time the bar stays closed) can damage the film.
5. Vent the bag. If the film isn’t perforated, cut a small slit or asterisk in it. This lets air escape during shrinking.
6. Shrink it. Start with the heat gun on low and well back. Move closer until the film reacts, and keep it moving. Uline’s manual says to work “in a circular spiral motion from the outside edges of the package first, and to the middle of the package last”. Stop when the film is tight and clear.

Don’t assume this vented package is airtight. Uline notes its I-bar system will “not create an airtight seal”.

With shrink bags and no sealer

Pre-made shrink bags are closed on three sides, so you only have to close one end.

1. Size the bag with its supplier’s chart. Check the item’s width, height, and distance around, plus extra for closing. A blanket “twice the size” rule doesn’t say which size to double. Uline’s dome-bag listing gives the largest basket diameter and height for that bag.
2. Close the open end. The neatest way is an impulse bag sealer. Uline recommends a heat sealer on its dome shrink bags before shrinking. Without one, fold the opening under the item and tape it with clear packing tape. Or gather and tie the top and trim the extra, as Wagner shows.
3. Shrink it with a heat gun, moving it evenly over all sides.

A taped or tied gift-basket closure is not proven airtight or tamper evident. Test the complete package before you make that claim. For products you sell, a sealer gives a cleaner result.

What doesn’t work

• A hair dryer. Uline says “hair dryers do not get hot enough”. PVC shrinks at about 250°F and polyolefin at about 300°F.
• Kitchen cling wrap or stretch wrap. Shrink film is stretched warm when it is made, so it pulls back when heated again. Cling and stretch wraps are not made to shrink.
• Punching vent holes with a hot tool. Clysar warns that drills and soldering irons fuse the film instead of perforating it.

L-bar setup and changeovers

For repeat production on an L-bar, keep a setup record for each product. It lets the next operator repeat an approved package without guessing. A changeover is the switch from one product to the next. Use the machine’s manual for the film path, allowed adjustments, startup, and shutdown. Threading diagrams and control values differ between models.

Record the starting setup

Keep setup values as records for one model. A timer number on one impulse sealer is not a temperature. You can’t copy it to another machine.

Thread the film

The HSE-100 manual has separate steps for film threading and platform adjustment. The Uline H-2378 manual describes its own film dispenser and separator. Automatic machines may add a powered unwind, an inverting plow, guides, and scrap take-up.

Find the fold and the open edges before loading. Follow the supplied diagram with the machine in the state the manual requires. Never reach into moving rollers or bypass a guard to thread film. If your accessories differ from the diagram, ask the supplier for the correct version.

Center the seal

The film must reach around the product without being pulled tight at the seal. Use the maker’s platform or seal-centering adjustment and the product’s approved orientation. See the worked sizing example for the sizes to give a supplier.

Check the seal before shrinking, then adjust the tunnel. If the bag is sound but the finished pack looks poor, use the troubleshooting guide. It helps you tell sealing, film-sizing, and shrinking problems apart.

Check the first package after a changeover

1. Confirm the product, film, machine setup, and recipe match the approved record.
2. Run samples using the manual’s startup steps with all guards in place.
3. Inspect the seal before shrinking and the finished package after it cools.
4. Confirm label readability, product stability, and the agreed look.
5. Record any approved setting changes and keep a typical sample.

This checklist is our own. It doesn’t replace the maker’s operating procedure. Have the equipment supplier do the first setup with your actual product and film.

Time each changeover

Time it from the last good package of the old product to the first good package of the new one. Include roll changes, mechanical adjustments, warm-up and settling time, trial packages, and cleanup. Count trial scrap separately.

During a buying trial, run one small-to-large and one large-to-small changeover. Add those minutes to cost per finished package. Put the procedure the supplier showed you in the operator handover. For wear parts and inspection records, see routine maintenance.

By product

Gift baskets

Use a dome shrink bag sized for the basket. Uline’s PVC dome bags are “designed for gift or food baskets” and have a vent hole. Use soft ribbon only. Burton + Burton warns that wired or burlap ribbon punctures the film. Close the bag under the basket and shrink from the bottom up. If the basket holds unwrapped food, check food-safe shrink film first.

Soap

The Handcrafted Soap & Cosmetic Guild says polyolefin lets scent through, perforated or not. It says 75 gauge PVC looks best when scent doesn’t matter. Perforated polyolefin suits soaps that need to breathe. Wrap only fully cured, dry bars. National ShrinkWrap notes that if film sticks to wet spots on a bar, heat will not fix it.

Candles

Uline lists its deluxe polyolefin film for candles. It uses a 5.5 in. candle as its round-item example, which needs 10 in. film. Wax softens under heat. Use a low heat setting, keep the gun moving, and don’t stay on one spot.

Books and printed materials

Uline recommends PVC for books, games, and office supplies. For soft or light products that might buckle, Uline sells Cryovac D-940, a soft polyolefin film that “won’t buckle or distort.”

Judge the whole package: the book or stack, its film, the seal, and the finish after shrinking. A machine that handles one rigid book may need a different feed setup for loose sheets or a mixed stationery bundle.

PAC Machinery lists books and printing among the uses for its Clamco 6750EL. That model has a soft start and stop meant to help keep stacked products aligned. This makes it a machine to trial. It doesn’t prove the machine works with every paper, ink, binding, or cover.

See I-bar sealer kits for small setups. See semi-automatic and automatic sealers for conveyor-fed lines. These are options to look into, not volume cutoffs.

Prepare samples. Send the supplier the thinnest book, thickest book, largest cover, and least stable printed stack you plan to wrap. Include any inserts, labels, sleeves, or backing boards used in production. Measure each item in the direction it travels through the machine. Decide how much movement inside the package is acceptable.

Ask the film supplier to suggest a grade and gauge for the trial. Compare the seal, clarity, ease of opening, and effect on the product. A material name alone doesn’t prove a film suits a printed finish. Use the film guide to write the spec.

Inspect the finished package. Use this checklist of our own for your trial:

• Does the stack stay square during feeding and transfer?
• Are corners, covers, and binding unchanged after the package cools?
• Are print, coatings, labels, and barcode scanning acceptable?
• Is the seal continuous without pulling the cover out of shape?
• Do film tails or loose areas get in the way when packing cartons?
• Can the recipient open the package without damaging it?

Photograph approved and rejected samples. Record the product, film, and machine settings with each one. A demo with a different book format doesn’t prove your whole range will run.

Measure the whole batch. Count good packages after shrinking and inspection. Include time for refilling stacks, film changes, trial rejects, and collecting finished goods. For mixed print jobs, time a changeover in both directions. Use cost per finished package to compare machines. Attach the approved sample and your acceptance rules to the buyer checklist. Keep the settings in a setup record.

Bottles and jars

For a tamper-evident band, slip a perforated shrink band over the cap and neck. Then heat it evenly all the way around. Uline says bands “must grip BOTH the bottle cap and the bottle neck to be considered tamper evident”. For a full wrap, confirm both distance around and container height with the film supplier. The diameter-only example above is not a universal formula for tall containers.

Safety

• Heat gun nozzles get very hot. The Power Tool Institute says nozzles can reach 1,000°F or more and take about 20 minutes to cool. Keep hands away from the front of the gun and keep it moving. Never leave it running unattended.
• Ventilate when using PVC. Eastey’s sealer manual warns that some films “may result in the release of hazardous fumes” at high temperatures. It says to ventilate at all times. PVC gives off hydrogen chloride gas when heat breaks it down (see PVC film). Polyolefin is not free of fumes under all heating conditions either. For every material, follow the film’s safety data sheet and the machine’s ventilation instructions.
• Keep a fire extinguisher nearby. Let the gun cool away from anything that can burn.

For heat gun choices, see shrink wrap heat guns. For a complete starter setup, see shrink wrap machines for home and small business. If packages come out wrinkled or with dog ears, see troubleshooting.