Bonding and Seam Sealing: Where Adhesive Replaces Stitch

Not every seam on a knit needs a needle. On a bonded garment the plies are held with adhesive film; on a seam-sealed garment the join is closed with tape. Either way the finished surface carries no stitch line and no needle hole. Both routes run on our bonded floor in Dongguan. Bonded and seam-sealed styles start at 200 pieces per style per colour, a sample takes 3–7 days and bulk takes 15–25 days after the sealed sample is approved. This page is about the construction itself: which route fits which seam, and what to state in the enquiry.

Two Routes That Share One Label

The word seamless is used for two different things, and the difference decides where the garment is actually made. Seamless knitting is a knitting route: the body comes off the machine as a tube, so there is no side seam left to close. Bonding and seam sealing are a joining route: panels are still cut — flat, shaped or laser-cut — and they are then held together with adhesive film, or closed with tape where a seam has to keep water out. On a knitted tube the shoulders and sleeves are still joined; the tube only removes the side seam.

Neither route is an upgrade on the other. A tubular body and a bonded placket can sit on the same polo: the body is knitted as a tube, the placket is bonded flat because a topstitch line would break the front. What decides the price is your list of seams — which of them you want bonded, which taped and which sewn — because that list is what the sample and the bulk run are costed against.

What Changes at the Seam

The same seam can be built in more than one way, and the route changes what the edge looks like, what sits against the skin and what the enquiry has to say. The table below is the checklist we work through when a bonded enquiry arrives.

Where Bonded Seams Earn Their Place

Bonding pays for itself where a stitch line would show or where a needle hole would matter. In knit programmes that means cuffs, hems and plackets on polos and T-shirts, the collar band on a shirt, the armhole and edge finishes on vests and base layers where a seam would otherwise sit under a pack strap, and side seams on a close-fitting body. On outerwear the argument is water rather than appearance: every needle hole is a way in, which is why a shell that has to hold a water column is bonded or taped along the seam. Decorative panels — a reflective strip, a shaped insert — can be applied by heat, with no stitch line or needle hole behind them.

Bonding does not make a garment cheaper, or better in every direction. A bonded seam is flat and carries no stitch holes; a sewn seam can be re-sewn if it fails, and a bonded one cannot. Where a garment has to survive hard wear and repair, a hybrid is often the honest answer — sewn where the seam is hidden, bonded or taped where it shows — and we will say so before sampling.

Film and Fabric Are Agreed Together

The adhesive film is not a stock consumable that works on everything. Film is matched to the fabric in the order: the film that holds a polyester interlock will not necessarily hold a cotton-rich knit or a brushed surface, and a silicone finish that feels expensive in the hand can stop adhesion altogether. So the film is chosen for your cloth, and the care label is written for the pair that was actually approved — not for bonding in general. If you supply the fabric, send the mill name, the composition and the finish with the enquiry, and we will tell you whether it bonds before you commit to a programme.

Before a sample is built we run a bond trial on your fabric: film, then a pull test and a wash cycle. You get the result before bulk is quoted, and the reading comes off your cloth rather than from a figure copied out of a standard. On a blend we have not bonded before, the trial decides whether the style goes ahead at all.

The Sealed Sample Is the Bonding Spec

Two samples are made. The first confirms construction and fit. The second is built in the bulk fabric with the approved film and confirms how the bond behaves on the cloth that will actually run; that is the one we seal. From that point it is the reference for the line and for inspection: bonded seams are checked against it for skip, bubbles, misalignment and incomplete adhesion, on top of the ordinary measurement and appearance checks. Settings taken from the approved sample are logged per seam type, and a drift from them stops the line rather than being noted and carried through the run.

That is why sampling is where a bonded programme is decided rather than inspected. Moving a bond line or resizing a panel after sealing sends the style back for a new trial, so raise it while the sample is still open.

The Minimum That Comes With Bonding

Bonded and seam-sealed styles start at 200 pieces per style per colour. Everything else in the catalogue starts at 100 pieces per style per colour, with sizes mixed inside a colour. The bonded figure is per style and per colour, so three colourways of one bonded polo are three minimums, and a different fit cut from the same fabric is a separate style with its own minimum. Non-bonded styles on the same purchase order stay at 100.

Sampling runs 3–7 days and bulk 15–25 days after you approve the sealed sample. Both are factory times and neither includes transport. Payment is T/T with a deposit and the balance before shipment, or L/C at sight on a full container. Goods ship EXW, FOB Shenzhen or Yantian, or DDP.

To quote a bonded style we need the reference sample or tech pack, the fabric with its composition and weight, the list of seams you want bonded rather than sewn, and the quantity per colour with the size range. Send those four things and the reply covers the route we would use at each seam, a costed quote and a sampling plan. Buyers still deciding between the routes can start with what bonded and seamless construction actually means, see finished builds in the seamless and bonded range, or read how seamless polo construction is specified. The sample lead time page covers what happens inside the sampling window.

Other processes on the same floor: the manufacturing overview, laser cutting, quality control.

Frequently asked questions

Is bonding the same as seamless knitting?

No. Seamless knitting is a knitting route: the body comes off the machine as a tube, so there is no side seam to close, though shoulders and sleeves are still joined. Bonding is a joining route: panels are cut and then held together with adhesive film, or closed with tape. A single polo can use both, with a tubular body and a bonded placket. The quote depends on which seams you want bonded, so name them in the enquiry.

Which seams can be bonded instead of sewn?

The positions where a stitch line would show or a needle hole would matter: cuffs, bottom hems, plackets, collar bands, side seams, neckline edges and decorative panels or inserts. Tape is used on seams that have to keep water out. Bonding can sit on the same garment as conventional sewing, so a style does not have to be fully stitch-free. Send the seam list with the reference sample and we will confirm which of them we would bond.

What is the minimum order for a bonded style?

Bonded and seam-sealed styles start at 200 pieces per style per colour, against 100 pieces per style per colour for the rest of the catalogue. The count is per style and per colour, so two colourways of one bonded polo are two minimums, and a different fit in the same fabric is a separate style with its own minimum. Non-bonded styles on the same purchase order stay at 100 pieces.

Can you use fabric I supply for a bonded style?

Yes. We buy from the supplier you nominate, or work with fabric you send. Because the film is matched to the cloth, the mill name, composition and finish matter as much as the weight: a silicone finish can stop adhesion altogether, and a brushed surface behaves differently from a flat interlock. We run a bond trial on your fabric before sampling, so the answer on whether it bonds arrives before you commit to a programme.

How is the care label decided on a bonded garment?

The care label is written for the film and fabric combination approved on that order, not for bonding as a rule. Heat re-activates the adhesive, so washing and drying instructions follow the pair that was tested, and the sealed sample carries the same instructions as bulk. If you know your customer will wash hot or tumble dry, tell us before the film is fixed, because that may change the construction we recommend.