Business Card Case With Covert Micro SD Compartment

I try never to be without a stack of business/calling cards, and now that I have a custom handbag and wallet, a custom card case seemed like the next logical step. In this case I've also added a compartment in the bottom with a trap door top that can hold a dozen Micro SD cards. Useful for me because I can securely carry extra memory for my camera, but also useful for anyone interested in covert data transport, since we all know that data can be the most valuable there is.

At present you could store 12 Micro SD cards that are 64gb each or 768gb total. Micro SD cards at 128gb each are on there way, and if you're part of a well funded "organization" you can probably already get them. This means the case could carry 1.5 terabytes. This is the same as carrying around 12,582,912 of the Macintosh computer from the legendary 1984 commercial, if you're keeping score at home. All of that plus a handful of business cards tucked into a chic clutch or computer bag.

Step 1: Supplies and Equipment

I've made extensive use of a laser cutter in my case's case, but you don't need one to make this project. I'm using precision cut bass wood that's meant for hobbyists and comes in a huge array of sizes. My notched panels could be replaced by simply stacking pre-cut strips of the right size and shape.

Supplies:

Bass Wood Pieces in 1/8 and 3/32 inch thick
Wood Veneer - 1/40 inch thick in assorted pieces and species - NOT paper backed
Wood Glue
Mineral Spirits
Wood Finish

Sand Paper - 100 to 400 grit
Clear Vinyl/Contact Paper
Utility Knife
Tweezers
Clamps
Scrap Wood (for clamping)
Toothpicks (for micro-gluing)


If you're using veneer and not laser cutting it, a sharp blade, straight edge and cutting mat will allow you to make a wide variety of shapes.

Step 2: Design

I've chosen an octopus motif for this case. I usually work in Illustrator with an 8 divisions per inch grid, but because I was using stock made in 32nd inch increments I changed up my grid to 32 divisions per inch. This was a great convenience, but it also meant that I created a pretty outrageously detailed design with strips of wood that are 1/32 of an inch wide. This was a stupid thing to do and you should not replicate my questionable decisions. No really, I found myself wondering why tweezers are so big and clunky. In fact, it would be wise to create a design that includes some standard Freemason symbolism because everyone knows that government officials send you peacefully on your way at the first hint you might be a member of the Illuminati. Nothing to see here, certainly not a dozen Micro SD cards...

The case itself is made in two layers to accomodate the sliding lid. I had originally considered adding a leather strap but I was able to keep my tolerances tight enough that the box stays closed by friction and doesn't need additional closure, especially since the case is usually inside a small clutch purse.

A dozen SD cards are fit under a false bottom - the lower level of the wood is engraved deeply enough for them to set into and there is an angled area at the end so that the false bottom can be tilted easily. 

I've included a .jpg of my layout for your convenience, but if you're building this yourself I would really encourage you to develop your own layout that is matched against your stock and specific needs.

The exterior of the box is made from pieced wood veneer. The only thing that really matters here is that it is cut to fit on the panels when the lid is slid out, other than that you can use whatever you like. If you're laser cutting the veneer you can make whatever shapes you want (though I'd try to keep everything at at least 1/8 inch, not the 1/32 by 3/32 I thought was reasonable.) If you're hand cutting - which and definitely be done with a sharp blade - straight lines will give you the best shot at visual perfection.

Step 3: Cutting and Piecing

I laser cut my pieces because I could (and I love laser cutting.) After cutting everything be sure to dry fit your pieces to be sure they fit right and work the way they should.

If you're piecing veneer like this my best results come from assembling everything face down on clear vinyl and then gluing entire sides all at once. Tweezers are great help for this, as well as a print of the flipped version of your design to work on top of.

I used lacewood for the body of the octopus and it's more or less made from loosely bound splinters. If your materials are equally unfriendly just collect up the broken pieces and assemble them in place. Once everything is glued and finished the break lines will be invisible.

Step 4: Glue the Case

Because of tight tolerances and tiny scale you'll want to sand your surfaces before gluing. I sanded off as much of the burn residue from the surfaces as I could and lightly roughed up the interlocking tabs. That's a difficult balance - cutting into the char will help the glue hold, but cut in too much and the fit will change. Bass doesn't have a lot of sap so it's not as important as it might be if you were using a pine or similar.

Glue the box parts in layers working from the inside out. Liberal use of clamps when drying will help everything set together properly. 

Step 5: Prep the Case for Veneer

After the case glue has set completely you'll need to prepare it for veneer. At 1/40th of an inch or so veneer doesn't forgive an uneven substrate. If you have any gaps in the tab gluing fill them in with more wood glue and let it dry.

Sand the box until all sides are even to the touch - you shouldn't be able to feel any surface variance. To keep the box square I lay my sheet of sandpaper down on a hard, flat table and rub the box on the sandpaper. If you have a bench style belt sander you could use that instead (you lucky duck!) Stick with a low grit sandpaper - 100 grit or so - because you want to leave a little texture for the glue to grab.

Step 6: Glue the Veener

Using surgical focus and laser-like precision cut the vinyl apart so that each panel of veneer is separate. 

Glue pairs of sides in sequence - both long sides, both short sides, etc. After each side sand down any extra veneer that extends past the edges on the box. Working this way keeps the reveals symmetrical. Of course, the reveals are about 1/40th of an inch, so it's not the end of the world if you don't make it perfect, but after placing 1/32 by 2/32" pieces of veneer I'm not ready to cut any corners now.

Spread a thin, even coat of wood glue over the panel you're gluing. Carefully place the veneer on the panel and then clamp it down to something hard and perfectly flat (I use a couple layers of plywood) until the glue is set. This prevents the edges of veneer from curling when they absorb the moisture from the glue. Sand the edges of that panel and move on to the next.

Remove the sliding door before applying the veneer to the edges of it. There's no way to sand the veneer down if it is too big and the door won't slide out, but you can sand the edges of the veneer before sliding it back in. Don't glue the box closed after this much work!

Repeat these steps until every side of the box is covered in veneer.

Step 7: Peel the Vinyl

Take your time with this, you can still kill your hard work dead. VERY, VERY carefully peel the vinyl from the veneer. Some small pieces will probably pop up with the vinyl, be ready to spot glue them into place. Apply the glue with something tiny like a toothpick, set the piece in place, lay a square of waxed paper over it and clamp it down until it's set. That will prevent it from warping or adhering to the clamp. 

Step 8: Sand the Veneer

If you have residue from the vinyl use a clean towel and mineral spirits to dissolve it and wipe it away. With a high grit sandpaper (I work up from 220 to 400) gently sand the veneer to smooth it out and clean up any laser marks. Use the same lay the sand paper on the table method as before. Don't use a belt sander here, you need precision. Keep going until the veneer is smooth and even.

If you have any large gaps you'll want to fill them in with a bit of wood filler.

When you're finished sanding go over the veneer with a clean towel and mineral spirits. The mineral spirits will help lift the sanding dust from the wood, which is especially important when you're using different colors of stock (maple dust disappears in maple, but is bright white against mahogany.) When the wood is dry go over it with a tack cloth to remove any remaining dust.

Step 9: Apply the Finish

I love my fast drying polyurethane but wood finish is a personal choice, just check out a few woodworkers forums. I would encourage you to use something that creates an actual film (not just an oil) to help secure any loose bits of veneer a bit more. If you're feeling extra fancy give it a light buff with some steel wool after the first coat of finish.

Remove the door before finishing because, again, you don't want to glue the box closed.

Step 10: Final Finishing

You may need to sand down the edges of the false bottom to make it fit - everything has been clamped and clamped again, and this can cause the box to shrink a bit. I finished the inside pieces of the box, too, to keep the engraving from shaking dust loose onto the SD cards. 

The box is ready to use - fill the lower section with Micro SDs, drop in the false bottom then add a stack of business cards.