3M™ Dual Lock™ Reclosable Fastener SJ3785, Roll Good with PSA, Stem Density 400, Black, 6 in x 50 yd, 1 Roll/Case, Bulk

3M™ Dual Lock™ Reclosable Fastener SJ3785 overcomes the often difficult alignment and installation problems of screws and hidden fasteners. It has a stem density of 400 stems per square inch and offers simple installation with no special 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.

How It Works
This reclosable fastener is designed to be attached to a variety of substrates using pressure sensitive adhesive. The fastener can then 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 for installation. This means that they can be used to attach components before they enter the final assembly plant, thus helping to reduce the number of parts and the length of assembly time.

Stem Densities
3M™ Dual Lock™ Reclosable Fasteners can be mixed and matched to meet the needs of the application. Combinations of stem densities and the engaged area provide adjustable and proportional engagement and disengagement force. Dual Lock™ fasteners are offered in three different densities (stems per square inch): 170, 250 and 400. The Dual Lock fastener SJ3785 has 400 stems per square inch (25mm), offering the tightest hold, and can be mated to Type 170 or 250. It should not be mated with another Type 400 fastener because the hold would be so tight that detachment would likely result in damage to the parts.

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. Some examples of applications include:

• Vehicle headliners


• Attaching accessories and equipment


• Attaching window and door trim panels


• Vibration and sound damping control


• CHMSL cover plates


• Center console flanges


• Interior trim


• Sunroof rings

3M Science Delivers Closures You Can Count On
3M thrives on defying conventional wisdom, like the concept that fasteners can both durably attach and easily separate. 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 multiple closures, look no further than the long-lasting durability of the 3M™ Dual Lock™ Reclosable Fastener SJ3785. It is yet another outstanding example of how 3M technologies advance operations in the automotive industry, providing both ease of use and superior results.