The Impossible Card Slip
Minimalism meets sophistication
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To get started, print off the PDF download below and check that the scale reference shows a 30mm square measured along any of it's sides. If not, please adjust the scale on your printer settings.
To begin, you will need two skins, one for the exterior, and one for the interior lining. For this project I have chosen 0.8mm calf leather in cognac for the exterior, and 0.6mm goatskin in navy for the lining.
You may vary these thicknesses if needs be. But I would not go too thick with the lining considering the need for wrapping and folding.
Firstly, you will need some card.
I like 350gsm (0.8mm) kraft card, but anything you can get your hands on is fine.
Use paper glue to stick your pattern onto the card, roll, leave to dry for a few minutes, then cut out on the line using a steel ruler.
After cutting out and preparing your patterns, place the body pattern onto your exterior skin and cut out. You can see I leave a healthy margin on the primary cut before trimming up to the pattern dimensions on the final cut. This will make it easier for you to cut out.
Cut out your lining from the provided pattern in much the same way. You may find it helpful to use a steel ruler against your pattern for extra support.
If you have less experience with a pattern or craft knife, a rotary cutter may be considered.
At this point you will have one piece of exterior skin and two pieces of interior skin cut accurately to the pattern dimensions provided.
Take your body pattern and place it down onto the flesh side of your exterior skin. Make sure each end is level with the pattern, then mark a centre line on each side.
Take a grooving tool, align the cutting tip so that the marks you made are centralised with the cutter. Now using a steel ruler, gouge a line so that at least 1/2 - 2/3 of the thickness of the exterior skin has been removed from the flesh side. This will reduce bulk and allow for an easier fold.
If you have a French edger, you can place one of the guides in the groove and remove the sides of the gouge so that it tapers a little more.
In preparation for lining installation, you are going to prepare each end of the exterior skin by roughening the first 2mm of the grain side like you see below.
I am using a piece of zinc plate here for accuracy using the roughing tool.
You can do the same to one end of the lining (one of the short sides of the rectangle). In this case I am using 0.6mm goatskin which is too soft for the technique pictured above, so I am simply roughening the grain side by gently scuffing backward for the first 2mm. This process will create a much better surface for gluing up.
Now that you have prepared the areas to be glued, you can add a layer of contact adhesive to the roughened parts only (2mm in from the edge). Do this on both the exterior and the interior skin.
When both parts to be glued are touch dry, you may carefully lay in each part, grain side to grain side, then gently hammer down.
Note that the lining is much wider than the main body, we will be trimming this flush later on, so leave an excess of lining each side.
Now take a set of wing dividers and use the body template to set them 3mm apart. Then you can use that measurement to transfer a line to the flesh side of the lining.
For marking out the holes we need for stitching in the French binding, I am going to use a 3mm stitching chisel. These are inexpensive irons available on eBay. While I rarely recommend these, they leave such a small slit
♢ ♢ ♢ ♢ ♢ which is perfect for what we need.
Regular irons that leave wide slits / / / / / can show a cut line when folded over later.
A pricking iron with a round point prong ° ° ° ° ° will also work, however you want a maximum of 3mm in size to avoid seeing a ripple in your turned edge.
Place the body pattern in line with the exterior skin you have chosen (cognac calf in this case), then copy over the marks. The pattern shows a 3mm stitch spacing.
Penetrate all the way through, we are not using an awl for this.
For thread, you want to select something that is very thin. This way your stitches won't show through the thin binding layer.
My favourite French binding thread has always been Gutermann Extra Strong (M782).
Inexpensive, very strong and widely available. Choose any colour as you are never going to see it on the finished product.
If you have a sewing machine, feel free to use it here as the saddle stitch provides no superiority.
No need to start your seam with a back stitch as it adds nothing here. The binding really doesn't receive much stress after the leather is folded over it - essentially you will be sealing the stitches in a leather tomb!
A single back stitch is fine to prevent loosening during the folding process.
Since Gutermann M782 is made from polyester I am carefully melting the ends down flat with a flame.
Once the seam is complete, tap down your stitches with a smooth hammer to flatten them completely.
Then, taking an adjustable creaser (or a single crease and a ruler), use a little heat to crease a line just below the stitches where we want the skin to fold cleanly.
This is not completely necessary, but if you have the tools, it makes the fold easier and cleaner.
Apply contact adhesive over the stitches up to the edge. Do this all the way along both seams on each side of the project.
Use a bone folder to gently start turning the leather over the stitches. Gradually go back and forth along the join turning a little more each time.
Be careful not to mark the exterior skin (cognac calf here) with your folder, so watch your pressure.
Finally, complete the turn so that the adhesive makes contact for an instant bond. I am using my fingers here feeling my way along, but you may use a bone folder if you feel more comfortable with it.
Now you may reinforce the bond by hammering the fold against a paring stone or another smooth clean surface.
Now, place a ruler along the centre of the groove you made earlier and fold over each side of the lining so that you can mark the centre on each side. A soft jaw clip can temporarily keep the lining tightly folded to make a more accurate measurement (see below images).
Allow the excess length of the lining to lay over the ruler (which is still aligned with your groove) and transfer the centre line with a white or metallic pen.
Once you have marked each side of the lining indicating where the centre of the card slip is, you may then use your ruler to trim off the excess.
After trimming, turn the lining over so that the flesh side is facing up, then skive down 5-8mm from the end to a thin feather edge as shown below.
Test that the skived end is in line with the centre of the card slip. If more needs to be trimmed, go ahead then re-skive if needed.
Take some contact adhesive, apply to the flesh side of the exterior leather as well as the flesh side of the lining leather.
The top edge of the exterior leather above the stitches should also have adhesive applied. This ensures an accurate fold.
Once the contact adhesive has become touch dry, place a steel ruler over the stitches and begin to raise the lining leather over the edge using a bone folder.
Now bring down each side of the lining leather so that the skived edges meet on the middle in the centre of the groove you cut earlier. Go slowly and make sure everything stays flat and true.
When you have completed this, use a roller to make sure the adhesive has full contact area with no air pockets.
Finally 'bone in' the skived ends into the groove where your roller won't reach.
The last step working the lining will be trimming the sides flush with the body leather.
Here I am using a round knife and a ruler, but a rotary cutter also ensures a neat edge.
Place the body pattern side by side with your project. The project will be slightly longer due to the addition of the turnover, but make sure it is centred.
Transfer over the marks at the end of the side seam with a round awl. This indicates the furthest position a pricking iron should mark the bottom of your card slip.
Now you can take your wing dividers and mark a 3mm line from the edge, all the way down to the mark indicating the end of the seam. You can use the seam line on your body pattern to adjust your dividers if needed.
Now you may take the pricking iron of your choice and penetrate through the body and the lining.
Start with the first prong in the middle of the French binding as shown below, but make sure the second prong does not nick the bottom of the binding. The top edge and the bottom edge of the binding should not be disturbed.
Here I am using a 3mm pricking iron by Wuta for reference.
The marks should continue down to the bottom, but they should miss the fold line where you created your groove on the inside.
Before you glue and stitch the side seams to close the card slip, you will need to skive the edges in order to to provide a more refined look to the project.
So simplify this step, take a grooving tool or compass race and adjust the guide so that the cutter is in the middle of the line on the side of the pattern, then tighten the guide to lock it in place.
Lining side up, start a groove about 2mm from the top edge so that no cuts can be seen on the finished article.
Continue to the other side, but stop 2mm short again for the same reason.
Do this to both sides of the project.
To finish the gouge made by the grooving tool, stop short, remove the tool and cut with snips or a sharp knife.
With a nice clean groove to follow, this may just be the easiest skive you can perform!
Remove the excess as below using a skiving knife or a French edger (skirt shave).
Much like the original groove, don't skive to the very end. Stop 2mm short and trim using a knife or a French edger.
Now that the edges have been thinned and the leather grain is open ready to receive adhesive, you can apply contact adhesive using a spatula all the way along both edges. Only glue where you have skived.
Now we can begin folding the project. A bone folder helps initiate the fold, or you can pinch the base with your fingers.
Making sure that the adhesive is touch dry, start the join at the top binding edge and work backwards to the base.
Only join one side at a time to focus on keeping the edges as aligned as possible. If you make a hash of it, carefully pull apart (or prize with a folder), re-apply adhesive and try again.
Hammer the edges down to ensure a strong bond.
As you have the hammer in your hand, pay some attention to the bottom fold and hammer it into a slimmer profile.
At this point, if you do not wish to use an awl as you saddle stitch your project, place your pricking iron back into the marks you already created on one side and follow through to the other side to finish them off.
Start your seam with two back stitches. Do the same when you get the the end and finish the seam with two back stitches. I am using 0.5mm linen thread here.
For a more in-depth course on hand stitching techniques, please see the video course
'The Techniques Of Hand Stitching', available with the purchase of any video Plan on this site.
Changing focus onto the edges now, take some sand paper glued to thick card and level the edges while removing any stray glue at the same time.
Iron down the surface in preparation for dye or edge paint. Take a manual creaser and heat over a flame before rubbing along the edge in one direction. If you have an electric edge creaser, take a wax spatula or creasing tip to perform the same action.
Apply your first coat of edge paint and allow to dry. If you are using pure vegetable tanned leather for the exterior and lining of your card slip, you may add dye before burnishing using your preferred technique.
For a more in-depth course on edge finishing techniques both burnishing and edge paint, please see the video courses 'Techniques Of The Edge', available with the purchase of any video Plan on this site.
Now that your edges are complete, it's time to create a cut-out at the base of your card slip. In this way we can use a finger to push the cards up and out of the card slip to operate.
I recommend pasting a sheet of graph paper onto a piece of card, then cutting the card out the same width and length as your project.
Marking a centre line will allow you to accurately make a cut out so that you can transfer onto your project accurately. Here I am using an English point punch.
You will note that the body pattern comes with an oval shape which you can cut out to use as a guide. This will work, however it is mainly for reference. So I recommend trying one of the examples below.
Apply stain or edge paint in this area to complete the card slip.
Your card slip is now complete!
Thank you for joining me in this build, I hope you have discovered new techniques that you can use in other projects too.
I personally carried this exact design for about 2 years and I can attest to it's durability with daily use.
As smartphones are now becoming a common way of purchasing, this design strikes a good balance of space saving and simple classic good looks.
With room for ID cards, business cards or back up payment cards, together with enough cash to get you out of trouble, this card slip will prevent bulky pockets ruining your look.
The perfect addition to your every day carry!
You can tap your card through the card slip to pay in stores without removing your card, but should you wish to add further security protection, RFID material can be placed between the exterior and the lining prior to gluing and stitching.
Please be mindful of the added thickness the material will bring.