Quick answer: Choose pinch bottom open mouth (PBOM) bags and a pinch bag closer like the PBC 6000 if you pack fine powders or food products that need a sift-proof, clean-looking closure with no needle holes, and you run enough volume to justify a production-line machine. Choose sewn open mouth (SOM) bags and a bag sewer if you use woven polypropylene, jute or burlap bags, pack coarser products like feed or fertilizer, or want a much lower equipment cost to start.
If you pack flour, pet food, feed, seed or fertilizer in bags, how you close the bag affects product protection, how the bag looks on a shelf, and your labor and equipment costs. Here's how the two most common closures for open mouth bags compare, and how to pick the right one for your product.
Pinch bottom vs. sewn open mouth bags at a glance
| Pinch bottom (PBOM) | Sewn open mouth (SOM) | |
|---|---|---|
| How it closes | Hot air reactivates pre-applied hot melt; the top is creased, folded and pressed shut | Thread is stitched through the bag top, with optional crepe tape over the seam |
| Bag types | Pre-glued multi-wall paper bags | Paper, woven polypropylene, jute, burlap, cotton and more (varies by machine) |
| Needle holes | None | Yes, along the stitch line |
| Sift-proof | Yes, when heat sealed | Not with a plain stitch; crepe tape improves the closure |
| Look on the shelf | Clean, square, retail-ready top | Visible stitch line |
| Speed (Cleveland Equipment machines) | PBC 6000: 30–75 ft/min standard | Pedestal heads: 35–55 ft/min (Model 100 up to 80); handheld: e.g., Model F at 38 ft/min |
| Equipment | Production-line machine; 230V or 460V power plus compressed air | Handheld units to pedestal sewing heads; entry cost is much lower |
| Best for | Fine powders, food, pet food and retail bags where a clean, sealed closure matters | Coarse or free-flowing products, woven or jute bags, lower volumes and tighter budgets |
What is a pinch bottom open mouth bag?
A pinch bottom open mouth bag is a multi-wall paper bag with a stepped top that has hot-melt adhesive already applied by the bag maker. The bottom comes sealed from the factory. After you fill the bag, a pinch bag closer reactivates the adhesive and seals the top.
How a pinch bag closer works
The PBC 6000 is an industrial hot-air pinch closer for pre-glued, multi-wall paper bags. Filled bags are carried through the machine on carry-through belts, which move each bag through four stations:
- Creaser: creases the bag top along the fold line.
- Folder: folds the flap over (a standard 1-3/4" fold, with an optional 2-3/8" fold).
- Hot-air manifold: heats and reactivates the pre-applied hot melt.
- Compression section: presses the fold closed so it bonds.
The result is a sealed closure with no stitching and no needle holes.
Advantages of pinch bottom bags
- Sift-proof when heat sealed. With no needle holes, fine powders stay in the bag. Bag makers describe heat-sealed pinch bottom bags as airtight on both ends.
- Better protection from contamination. A sealed closure leaves fewer openings for dust, moisture or outside contaminants to get in.
- Retail-ready look. Pinch bottom bags have a clean, square profile that displays well on a store shelf and stacks neatly on a pallet.
- Barrier options. Bag suppliers offer pinch bottom bags with coated plies, film liners or greaseproof paper for extra moisture and grease resistance.
- Less labor and upkeep. Bag makers note pinch sealing is less labor intensive and needs less maintenance than sewing. There's no thread to change or needle to replace.
Drawbacks of pinch bottom bags
- Paper bags only. Pinch closers are built for pre-glued multi-wall paper bags, not woven polypropylene, jute or burlap.
- Bigger equipment investment. A pinch closer is a production-line machine and costs far more than a sewing head.
- More utility requirements. The PBC 6000 needs 230V or 460V power and clean, dry compressed air at 90 PSI.
What is a sewn open mouth bag?
A sewn open mouth bag is closed by stitching thread across the top after filling. It's a very common closure because it works with many bag materials and the equipment is simple and affordable. For a cleaner, more durable closure, crepe tape can be folded over the top and sewn in place.
How a bag sewer works
A bag closer sews a chain stitch across the bag top. You can do it by hand with a portable closer, or on a conveyor line with a pedestal sewing head:
- Portable (handheld) closers like the NP-7A, Model S and Model F are carried to the bag. They're common in warehouses, farms and smaller operations.
- Pedestal sewing heads like the Model 100 plain sewing head and the Fischbein Empress Model 101 tape sewing head mount on a pedestal and work with conveyors for continuous production.
Advantages of sewn bags
- Works with almost any bag material. Our sewing heads and portable closers handle paper, woven polypropylene and jute, and several also sew burlap, cotton or plastic bags.
- Much lower entry cost. A handheld closer or pedestal sewing head costs a fraction of an automatic pinch closer.
- Portable options. A handheld closer like the Model F weighs 12 lb and can go wherever the bags are.
- Crepe tape upgrade. The Empress Model 101 sews crepe tape over the bag top for a cleaner, more durable closure, and the Model F offers an optional 2" crepe tape attachment.
Drawbacks of sewn bags
- Needle holes. Stitching punctures the bag, which can let fine powders sift out and weaken the seal.
- More hands-on work. Sewing closers need thread changes, adjustments and regular maintenance.
- Less polished look. A stitched top reads as industrial, which matters less for feed and fertilizer than for retail food and pet food.
Which closure is right for your product?
| Product | Usually the better fit | Why |
|---|---|---|
| Flour, bakery mixes, powdered dairy | Pinch bottom | Fine powders sift through needle holes; food products benefit from a sealed closure |
| Retail pet food | Pinch bottom | Clean, sealed closure and a shelf-ready look |
| Industrial and agricultural chemicals | Pinch bottom | A sealed closure helps keep product in and contaminants out |
| Animal feed, seed, lawn fertilizer | Either | Sewn is common and economical; pinch bottom adds sealing and a retail look |
| Anything in woven polypropylene, jute or burlap bags | Sewn | Pinch closers are built for pre-glued paper bags only |
| Low volume or closing bags in the field | Sewn (portable) | Low cost and portable |
5 questions to ask before you switch to pinch bottom bags
- Does your product sift? If fine powder leaks from sewn seams or dusts your warehouse and trucks, a sealed pinch closure solves it.
- Where is the bag sold? Retail shelves reward a clean look. Farm and industrial buyers usually care less.
- What bag material do you use? Pinch closers need pre-glued multi-wall paper bags. Talk to your bag supplier about pinch bottom versions of your current bags.
- What's your daily bag count? The PBC 6000 is built for production lines with manual or automated infeed. At lower volumes, a sewing closer is usually the more economical choice.
- Do you have the utilities? The PBC 6000 needs 230V (1 or 3 phase) or 460V (3 phase) power and clean, dry air at 90 PSI and about 420 SCFH.
PBC 6000 pinch bag closer: key specs
- Bag type: pre-glued, multi-wall paper bags
- Speed: 30–75 ft/min standard range; higher speeds depend on the application
- Bag size: variable width; up to 56" (1,422 mm) long; 6" (153 mm) free top for standard folds
- Fold: 1-3/4" standard; 2-3/8" optional
- Controls: digital temperature control with readout, variable speed (AC VFD) and a bag counter
- Safety: emergency stop, two-hand close buttons, bag-jam detection, over-temperature sensor and airflow protection
- Maintenance: air scrubber to clear dust and debris; front breakaway swing channel for access
- Frame: adjustable height, with casters
- Power: 230 VAC 1 or 3 phase, 60 Hz, or 460 VAC 3 phase, 60 Hz
- Air: clean, dry, non-lubricated air at 90 PSI (6.2 bar), about 420 SCFH
- Weight: about 795 lb (360.6 kg)
Frequently asked questions
What is the difference between a pinch bottom bag and a sewn open mouth bag?
A sewn open mouth (SOM) bag is closed by stitching thread through the top of the bag, sometimes with crepe tape over the seam. A pinch bottom open mouth (PBOM) bag is a multi-wall paper bag with pre-applied hot-melt adhesive. A pinch bag closer uses hot air to reactivate that adhesive, then folds and presses the top closed. The pinch closure has no needle holes, so it can make a sift-proof seal. The sewn closure works on more bag materials and costs much less to start.
Are pinch bottom bags sift proof?
Yes. When a pinch bottom bag is heat sealed, the closure has no needle holes, and bag manufacturers describe the result as a sift-proof package. That's why pinch bottom bags are common for fine powders like flour, bakery mixes and powdered dairy products.
Can a sewn bag be sift proof?
A plain sewn closure leaves needle holes, so fine powders can sift through. Adding crepe tape over the stitched seam, with a tape sewing head like the Fischbein Empress Model 101, gives a cleaner, more durable closure. For fine powders that must not sift at all, a pinch bottom closure is the stronger choice.
What bags can the PBC 6000 close?
The PBC 6000 is an industrial hot-air pinch closer for pre-glued, multi-wall paper bags. It handles variable bag widths, bags up to 56 inches long, and a 6-inch free top for standard folds. It is not designed for woven polypropylene, jute or burlap bags. Those are closed with a bag sewer.
What products are usually packed in pinch bottom bags?
Pinch bottom bags are common for flour, bakery mixes, pet food, powdered dairy products, animal feed, feed additives, agricultural seed, lawn fertilizer and industrial or agricultural chemicals. These are all applications the PBC 6000 is built for.
Is a pinch bag closer faster than a bag sewer?
They're in a similar range. The PBC 6000 runs 30 to 75 feet per minute in its standard range, with higher speeds depending on the application. Pedestal sewing heads like the Model 100 run 35 to 55 feet per minute and up to 80. Where the pinch closer tends to save time is labor and upkeep: bag makers note that pinch sealing is less labor intensive and needs less maintenance than sewing.
How much does it cost to switch from sewn bags to pinch bottom bags?
The biggest cost is equipment. Handheld bag sewers and pedestal sewing heads cost far less than an automatic pinch bag closer like the PBC 6000, which is a production-line machine. You'll also need pre-glued pinch bottom bags from your bag supplier, plus the right power and compressed air. Call us and we'll help you compare the full cost for your line.
What do I need to run a PBC 6000?
The PBC 6000 needs 230 VAC (1 or 3 phase, 60 Hz) or 460 VAC (3 phase, 60 Hz) power, plus clean, dry, non-lubricated compressed air at 90 PSI and about 420 SCFH. It works with manual or automated bag infeed, and the standard machine weighs about 795 lb.
Can I close pinch bottom bags with a sewing machine?
Pinch bottom open mouth bags can be sewn, but they're usually closed on a pinch closer so the pre-applied hot melt forms a sealed, sift-proof closure. Sewing them gives up the main benefit of the pinch bottom design.
Not sure which closure fits your line?
Tell us what you're bagging, your bag type and size, and how many bags you close per shift, and we'll recommend the right closer. Call 866-888-6327 (Mon–Fri, 8am–5pm CST), email sales@clevelandequipment.com, or see the PBC 6000 pinch bag closer.