Slittack

Slittack is a fabrication term used to describe a jointing method that combines a slit cut in a base sheet with discrete fasteners or welds to secure an adjoining piece. The technique aims to provide provisional alignment and load distribution while reducing heat input and distortion relative to a full weld or seam.

In practice, a narrow slit is produced along a defined path on the base material. A mating tab, edge, or panel is positioned to intersect the slit, and fasteners or tack welds are applied at spaced intervals along the contact line. The assembly may then undergo further bonding, sealing, or finishing steps as required. Advances in cutting methods, such as laser or precision milling, enable tight tolerances and clean slit edges, which can improve fit without excessive distortion.

Slittack is used with a range of materials, including aluminum and other metals, stainless steel, and certain fiber-reinforced composites. It is particularly favored in applications where precise alignment is critical and where minimizing heat-affected zones is beneficial, such as in aerospace panels, automotive trim components, and architectural cladding.

Variants of slittack differ in the way the slit is prepared and how the fasteners or welds are applied. Compared with traditional butt or lap joints, slittack can offer improved alignment control and reduced distortion, though it may provide lower ultimate strength and require additional bonding or finishing steps.

See also: tack weld, slit joint, seam weld.