IKEA Flottig lunch box clasp replacement

The IKEA Flottig lunch box remains popular among those who own one, in spite of the product being discontinued.

Unfortunately, it is possible for the clasp to break, or get knocked off the lid and become lost. Without the clasp, the lunch box becomes useless because the lid cannot be attached to the box, and the carrying handles are part of the lid.

Here's a replacement clasp that actually works better! It was tested on several children aged 7-10, who could knock off the original clasp easily, but not this new clasp. Make your lunch box last longer!

There are two versions of this clasp:

• PETG or ABS version (recommended): Print flat
• PLA version: Print on its edge

The reason for the PLA version is because PLA is brittle, and printing it flat may result in breaking the latching clip due to high stress that can split layers apart. By printing it on its edge, the clip has no layer lines to break; the perimeters take the load instead of the layer interfaces. This is especially important if you're using “silk” PLA, which has poor self-adhesion.

PETG and ABS have good self-adhesion, so this can be printed flat, and this version matches the shape of the original clasp.

The example pictured was printed with transparent PETG, which becomes translucent white when printed.

Print settings

Printer: Prusa MK3S

Supports: Yes (for both versions), for angles less than 35° from horizontal

Resolution: 0.4 mm nozzle, 0.2 or 0.3 mm layer height

Other: 3 perimeters, 25% cubic infill, octagram spiral bottom layer infill

Supports are needed only for the hinge area of the clasp. The hinge clip needs no supports. For the PLA clasp printed on its edge, use organic suports (PrusaSlicer) or tree supports (Cura).

Three perimeters are necessary for strong, solid hinge clips.

Post-printing / assembly

1. Remove the support material.
2. Slide the clasp hinge pins inside the U-shaped clip.
3. Push the clip onto the tab in the lunch box lid. This requires significant force. You may need some pliers, with one side of the jaw on the box rim and the other side on the back of the clip.
4. Enjoy your repaired IKEA Flottig lunch box.

How this came about

I replied to a request on Reddit to make a replacement clasp for the IKEA Flottig lunch box, and I offered to do it for free. The requester became my assistant in this project, sending me me detailed dimensions, photographs, and videos, including the video linked above.

Everything went right on the first try with no additional design-and-print iterations needed. That hardly ever happens!