3M™ Dual Lock™ Reclosable Fasteners SJ3249, Slide-in Piece Part, Black, Stem Density 400

Designed to Hold
3M™ Dual Lock™ Reclosable Fastener SJ3249 is a black, polypropylene reclosable fastener with a 25.4 mm x 28 mm, slide-in, rectangular base with extended edges and a stem density of 400 stems per square inch. This product overcomes the often difficult alignment and installation problems of screws and hidden fasteners, offering simple installation with no additional tools required. 3M™ Dual Lock™ Reclosable Fasteners are positive-locking, blind fasteners designed for attaching automotive trim components. The products feature mushroom-shaped polyolefin stems that snap together, forming a high tensile closure. Dual Lock fasteners are used primarily to secure rigid and semi-rigid surfaces such as trim or door panels, instrument panel bezels, headliners, and other automotive interior and exterior trim.

These fasteners attach without the use of pressure sensitive adhesive, and come with a variety of bases that can slide into holes of precise dimension. They are easy to install and require no special equipment or skills. Stems also offer more strength than hook and loop closures yet still easily peel apart.

How It Works
This pop-in fastener is designed with extended edges to be inserted into a same-width channel where attachment is desired. The polypropylene base grips the inside of the channel and holds tight. The fastener can be mated to a second Dual Lock fastener attached to a piece of trim or other part – when the two fasteners mate, the two parts are firmly secured together.

When two pieces of 3M™ Dual Lock™ Reclosable Fasteners are pressed together, the stems flex and the mushroom heads slide past each other. After passing the opposing mating piece, the stems snap back into their original position and the opposing mushroom heads interlock. These fasteners can provide high tensile strength but can be opened by simply cleaving or peeling open the closure.

Alignment and re-alignment are easy and no special tools are required. This means that the Dual Lock fastener can be used to attach components before they enter the final assembly plant, helping to reduce the number of parts and assembly time.

Stem Densities
Combinations of stem densities and the engaged area provide adjustable and proportional engagement and disengagement force to meet application requirements. Dual Lock fasteners are offered in three different densities (stems per square inch): 170, 250, and 400. The Dual Lock fastener SJ3249 has 400 stems per square inch (25mm), offering the tightest hold, and can be mated to Type 170 or 250.

Recommended Applications
3M™ Dual Lock™ Reclosable Fasteners can replace conventional mechanical fasteners in a wide range of assembly and attachment applications where reclosability or serviceability is desired. Dual Lock fasteners are used primarily to secure rigid and semi-rigid surfaces such as trim or door panels, instrument panel bezels, headliners, and other automotive interior and exterior trim. Other application examples include attaching accessories and equipment, window and door trim panels, sunroof rings and vibration and sound damping control.

3M Science Delivers Closures You Can Count On
3M™ Dual Lock™ Reclosable Fasteners are ideal for many applications where a high strength, reclosable fastening system is required. 3M engineers have uniquely combined physics and materials science to bring the automotive industry reliable fasteners that supply high performance even after exposure to high moisture levels and wide temperature ranges. For applications that require a slide-in piece and multiple closures, look no further than the long-lasting durability of the 3M™ Dual Lock™ Reclosable Fastener SJ3249. It is yet another outstanding example of how 3M technologies advance operations in the automotive industry, providing both ease of use and superior results.