KC Wallet

Introduction

The KC Wallet is my idea of a perfect wallet (which I'm able to make ;).

My criteria were the following:

• As thin as possible
• As close as possible to credit card size
• Variable number of cards
• Extra compartment for banknotes

Thanks to the Prusa MK4, I was able to make this wallet a reality, as I finally dared to print TPU, which I needed for a durable and thin hinge.

Instructions

Parts needed:

• Two (+1 optional) printed parts
• Elastic band (max. 20mm wide)
• Needle and yarn

Printing:

Bottom.3mf + Sewing_Aid.3mf (optional)

Printing these parts is very easy. I chose PETG and a layer height of 0.2 but you can choose whatever you like.

Money.3mf

This is the special and hard part of the wallet (apart from sewing). I wanted to have a stiff part with a soft durable hinge. So I tried to print a TPU hinge between some layers of PETG.

You can either use the already sliced Money_PS.3mf file or follow this guide to printing the part with only one extruder. If you have multiple extruders, you can omit or adjust a few of these steps:

1. Load the Money.3mf file in PrusaSlicer
2. Cut the part at Z: 0.2 mm and select ‘Cut into: Parts’
3. Cut the part at Z: 0.6 mm and select ‘Cut into: Parts’
4. Go to ‘Print Settings’ → ‘Multiple Extruders’ → Disable ‘Wipe tower’
5. Go to 'Printer Settings' → 'General' → ‘Capabilities’ and set Extruders to 2
6. Go to 'Printer Settings' → 'Custom G-code' → scroll down to ‘Tool change G-code’: Add M600
7. Select the layer height, filament and extruders as shown in the picture:

I chose the generic PETG and FLEX profiles as filament profiles. Of course you can also choose your own profiles. Instead of PETG you can probably also use other filaments, I have only tested PETG so far.

A layer height of 0.2 mm is important and don't forget to change the extruder of the middle part (Money_A_B) to extruder 2 (the one with TPU).

In the end it should look like this:

• Layer 1 → PETG
• Layer 2+3 → TPU
• Layer 4+5 → PETG

Sewing the elastic band:

You need to create two rings from the elastic band. For the large ring you need an elastic band with a length of about 17 cm and for the small ring you need a piece with a length of about 12 cm. I have absolutely no idea about sewing. So if you know a better technique, feel free to use it and tell me about it :)

You can use the sewing aid if you like. I tried it with and without and I actually don't know which I like better. If you use it, I would start with the large ring…

… flip the large ring around and sew the small ring to the other side.

Assembly:

Position the two printed parts as shown in the picture and pull the large ring over them. Make sure that the cutout for the thumbs is on the bottom half and the small ring is on the top half.

You can then slide your cards between the printed parts....

…and clamp the banknotes in the foldable part under the elastic band.

Done!