Indestructible Slim Wallet

I think wallets should be cooler and shouldn't deteriorate! I've had a leather wallet for ages, and I've noticed the signs of wear and tear over the years, so I wanted to make something extremely durable that also looks cool.

I am a college student that has access to a bunch of fancy machinery, but this wallet can also be 3D printed, made with a bandsaw, water jet, etc. It is essentially a couple of flat pieces of metal

Disclaimer: I originally set out to design a completely new design, but after doing some research, I found the Ridge wallet. The design work I did was to recreate the design based on images and some guesswork, and design it with the intent of laser cutting all the parts.

Materials

• 1/32" Aluminum sheet metal (Aluminum is optional, the design can also be laser cut with acrylic)
• 1/16" Aluminum sheet metal (Aluminum is optional, the design can also be 3D printed)
• .75" elastic band (Any thickness between .5" and 1" is usable, 1" might actually be optimal)
• Short M3 screws
• Sewing needle & thread
• Glue/Epoxy

Tools

• CAD software - Fusion 360 (Any other CAD software can be used, I used Fusion 360 though)
• Metal laser cutter (optional, bandsaw & drill is the alternative, a waterjet also works)
• Powder coating system (optional, spray paint is the alternative)
• Laser cutter (optional, only needed for engraving)

After looking at some references, I began designing the wallet.

I began with modeling a credit card so I could reference it later in the design, as a way to sort of check myself along the process. I looked up the dimensions for a credit card and added a fillet to the credit card.

Next, I did an offset, since I wanted my wallet to be slightly larger than the credit card, and so the wallet would keep the general shape of the credit card.

I added a circle cut out in the corner, which exists so that it's easier to push credit cards out.

This rectangle will be the basis for the outer layers.

Based on that, I started to create the inner part of the wallet. It is supposed to be a shape where a cutout for the elastic band can go.

I made a T-Shape cutout the thickness of my elastic band, since the idea is that the elastic band keeps the wallet closed and cards from falling out. I also made it slightly larger to allow for some tolerance.

I then added holes for my M3 screws to go through. Each of the 3 inner parts needs two holes, so that it is properly constrained and won't rotate when assembled. The holes are slightly smaller than M3 so they can sort of self-thread in.

I checked against my model of the credit card and realized that the wallet was larger than I wanted it to be, so I went back in the history browser and decreased the offset.

I also went back and changed the dimensions of my T-Shape cutout, since I realized that my elastic band was .75" rather than 1", which I originally assumed it was.

I imported an SVG image of something I wanted to engrave on a sketch and added it to my model.

These 4 parts (The outer face, the 3 inner parts) are all the CAD that needs to be done, since the wallet is created with only these 4 parts, just with 4 copies of the out part, and 2 copies of each inner part.

(If you only have a 3D printer, you can go ahead and print this part twice and go to step 5 then 8)

I then exported my files. My favorite way to do so it to project the geometry of the face onto a blank sketch, then right click and do save as DXF to get it into a format usable for laser cutting. You do not need to worry about the features you want engraved right now, that can be done on a traditional laser cutter after everything else.

I imported my files into the metal laser cutter software and ran the metal laser cutter. I initially tried to engrave using the metal laser cutter, but it didn't work out as great as I wanted, so I pivoted and used a different engraving method later on.

I cut the inner pieces with the thinner 1/32" aluminum and the outside with the thicker 1/16" aluminum. In hindsight, it was more optimal to make the inner pieces with the thicker aluminum as well, as I ran into some small tolerancing issues later on for using thinner aluminum there. (The thickness of the elastic was very slightly thicker than the thickness of the aluminum)

Also, the aluminum looks like a different color in the third photo because of the lighting.

If you don't have access to a metal laser cutter, these parts can also be waterjet. You could also make these parts with a band saw and a drill, although it may be difficult.

I used my .75" elastic band here. I folded it over along one of the lengths, then cut it slightly longer. This gives me an elastic band a little more than twice the length of the inner gap. I did the same thing for the other length. You can increase the length of the band if you foresee yourself having a lot of credit cards.

I then sewed the two parts together and tested it by putting it on the wallet. M3 Screws can be screwed in here temporarily so that you can more easily test the fits. You don't want the elastic band sagging like in the 5th picture, if it is, then the length of the band needs to be redone to be longer, as it is too tight. It should make a perfect T shape, without being too loose.

Powder coating parts isn't terribly difficult, but it does require some special equipment.

To powder coat my parts, what I did was hang my parts up with a wire, then ground that wire electrically. I then sprayed powder at the part, and the powder sticks due to an electrostatic charge.

Afterwards, I put it into the furnace at about 425 degrees Fahrenheit for 10 minutes, so the powder would bind to the aluminum.

After 10 minutes I removed the parts and hung them back up to cool.

If you don't have the ability to powder-coat, spray painting is a viable alternative.

Laser engraving Aluminum can be done on most traditional laser cutters, but if you are not sure, you should check with someone, as putting the wrong materials in laser cutters could cause fires.

First, I exported the file I wanted to engrave into the laser cutter software (the resized SVG image from step 2), then I set the inner area of the drawing to the blue color, and the outer area to the black color. This tells the laser cutter to go max power on the outer lines and have less power on the inside. What this does is it reveals the aluminum behind the powder and darkens it elsewhere.

Then I inserted my parts and ran the laser cutter. Before doing this however, I also created and powder coated a random piece of aluminum to test settings on, until I ended up with settings I was happy with.

It is important to make sure that the cut is centered, I ended up putting in my a little off, so my engravings came out a little off center.

I used a little bit of epoxy and super glue to glue the inner part to the outer faces, then I clamped them together and let the bind.

Normally, the M3 screws should be enough to hold them together, but I ended up making my holes slightly too large that they wouldn't tighten fully.

The assembly order for one half is a sandwich. Outer face, then the three inner pieces, then the band, then the outer face. After that, it goes inner face, the three inner faces, the other end of the band, then the last outer face.

You can optionally put in the screws, but glue is generally enough. If the screws are too long you may have to sand/cut them down, so they don't scratch your credit cards.

After gluing together all the parts and screwing them together, you now have an awesome functional and slim wallet!

I've found that the number of cards it can hold is dependent on the length and elasticity of the band. I was able to hold all five cards that I own though, but it is likely able to hold more as well.