Choosing the Right Zipper
So many projects, from boat covers to pillows and everything in between, use zippers. When it comes time to select a zipper for those projects, however, all of the options and variations of zippers can be overwhelming. If your zipper chain is intact, but you just need a new zipper slider, read our blog, "Choosing a Replacement Zipper Slider" (#300081XHT). To help you select the right zipper size and type for your next project, we've written this very helpful blog that explains everything you need to know about zipper selection. Coil, molded tooth or metal, continuous or finished, locking or non-locking — don't worry, we explain it all.
Let’s start off with zipper sizes. Zippers are sized with a number designation (e.g. #5, #10). These numbers are based on the approximate width of the zipper teeth in millimeters when the zipper is closed. So a #5 zipper’s teeth measure approximately 5mm across, a #10 zipper’s teeth measure approximately 10mm across, and so on. For exact measurements, look under the Specifications tab on each zipper's product page. This makes it easy to select a size because the bigger the size, the larger the zipper teeth will be.
Sailrite® stocks zippers in the following sizes:
Size #4.5: Used for small home décor projects such as cushions, pillows and purses.
Size #5: Used for medium-sized projects such as upholstery, duffel/tote bags, backpacks and jackets.
Size #10: Used for large projects such sail packs, boat covers, marine enclosures and tents.
Size #15: Used for very large projects like oversized sail packs and covers, large tents, and portable buildings and greenhouses.
Coil, Molded Tooth or Metal
One way to narrow down your zipper selection is by the type of tooth on the zipper. There are three main types: coil, molded tooth and metal. On YKK® brand zippers, the molded teeth are called VISLON®. It's the most common marine zipper, and it features teeth made from Delrin® plastic that are molded onto the zipper tape. This construction makes them strong and practically weatherproof. VISLON zippers come in sizes #5, #10 and #15.
Coil zippers feature plastic teeth that, as the name implies, look coiled. The teeth are sewn onto the side tape with polyester thread. Coil zipper teeth are stronger and more flexible than molded tooth zippers, making coil a great choice for curved applications. Coil zippers are available in #4.5, #5 and #10 sizes.
Metal zippers are their own separate entity, and have polished metal teeth that secure together on the zipper chain. They are ideal for bags and purses, backpacks, interior cushions and upholstery, and more. You'll find a selection of these products on our website.
Continuous vs. Finished
Continuous and finished are terms that refer to the length and style of the zipper as a whole. Finished zippers are sometimes also called "jacket zippers" because they are most commonly used on coats and jackets. Finished zippers feature a starter box and pin at one end of the zipper tape and a zipper stop at the other end. These zippers also come with sliders included. Finished zippers are used for applications where you want the sides of the zipper to separate completely, such as on a coat, a genoa sleeve or the side panels of a cockpit enclosure.
A continuous zipper is a little different. These zippers do not have a beginning or an end point (no starter box or zipper stops). Continuous zippers are usually sewn into a project at both ends like on a bag, tent or cushion. These zippers do not come with sliders, so you will have to purchase one separately and add it to the zipper chain. If one or both ends of your continuous zipper isn’t sewn shut, you can add zipper stops to the chain to keep the slider from falling off the end of the chain.
Locking vs. Non-Locking
The terms "locking" and "non-locking" refer to the zipper sliders. Locking zipper sliders have a small lock mechanism in them that keeps the slider in place unless the slider’s tab is pulled. This prevents the slider from moving on its own if the tape is forced apart or if the center of the slider is pushed.
Non-locking sliders, on the other hand, allow the zipper to separate by pulling on any part of the zipper slider or even by pulling the zipper teeth apart. This is useful for an application where you need to be able to quickly separate the zipper, like on a genoa sleeve.
Locking and non-locking zippers are available for coil, molded tooth and metal zipper teeth. When selecting a slider, be sure you choose a slider that is compatible with your zipper chain in both size and type. For example, a #5 molded tooth zipper will need a #5 molded tooth slider, and so on. Then, you can select the slider material (plastic or metal) and locking or non-locking. We also recommend sticking to the same brand for zipper parts. Pairing a YKK slider with a YKK zipper chain will offer the best compatibility and performance.
Ready to shop for your zippers? Browse our large selection of YKK zippers right here at Sailrite. Need a waterproof zipper? YKK® AquaGuard® Water Repellent Zippers are coil zippers with a polyurethane coating to keep water out.
Do you have any other questions about zippers? We're here to help! Share your questions and concerns in the comments.
Footnote: This blog was updated in June 2020 to include mention of metal zippers.