A Dry Bag Usually Leaks at the Mouth, Not Through the Fabric

A Dry Bag Usually Leaks at the Mouth, Not Through the Fabric

The leak emails we get are rarely about a hole in the middle of the cloth. Someone packed a phone and a spare layer, trusted the roll, and opened a wet bag at the end of the day. The panel is usually intact. Water came in at the mouth, or along a weld that looked sealed on the sample table and then opened after the bag sat folded in a carton.

A roll-top stays dry because the opening is folded down on itself. Three folds, if the skirt is long enough, then the buckle. Each fold is a wall the water has to climb. Two folds feel closed when the bag is empty on a desk. Once it is full, the top is under tension and two folds often are not enough. The opposite problem shows up on stiff cloth: the skirt is long, but the buyer cannot get the buckle across without a wrestle, so they stop early and call that shut.

The buckle tells you if the pattern is wrong

When we cut a new size, we fill the bag and see whether three folds still land with the buckle sitting straight. A buckle that hangs off to one side chews one edge of the strap. After a season of being dragged across a kayak deck or thrown in a car boot, that edge is where the roll starts to creep open. It looks like a hardware fault. It started as a pattern that was a centimetre short.

Carsikie has made these in Foshan since 2008. The small end of the range is the 5L camping ocean bag, JA053, an orange roll-top we list in 600D PVC or TPU. The 30L ocean pack is JA050. Sizes between those are cut when an order actually needs them. On the site we say the bag floats once the seal is closed. People test that in a pool. If the roll was never really closed, it sinks, and the email says the material failed.

Welding is the other half, and photos hide it

PVC and TPU dry bags on our floor are thermo-welded. A stitched seam in coated fabric is a line of holes unless something seals them afterwards. Welding melts the coating into a joint. It can still be wrong. Too much heat thins the cloth and it cracks the first time someone folds it hard. Too little heat leaves a joint that looks shiny and peels when a strap is yanked. A close-up from the studio will not show either one.

Pull the sample weld with your thumb. If the edge whitens and splits, that setting is not ready for your order. We would rather you do that in the sample room than discover it after a retailer has the goods.

Three checks that take less time than another email

Fill the bag with a towel and a bottle, roll it, and lay it on its side in a tub for half an hour. Standing it upright only tests the bottom seam, which is almost never the one that fails.

Carry it by the shoulder strap, not the little grab handle. On a light ocean pack the strap patch is where the cloth tears out. The strap on our dry bags is detachable and slides, so try it at two lengths, not just the length it arrived on.

Leave it rolled and clipped overnight. Some buckles relax. You want to see a gap before the bags are on a boat, not after.

If you are lining up factories, ask for a short clip of the weld on your cloth, and send the size you actually sell. A 10L that has to swallow a magazine and a phone is a different pattern from a 10L drawn to look roomy in a listing.

Quotes go through Joan: joanbags2022@126.com, WhatsApp or WeChat +86-13922536806.