Intro: Wet Molding a Leather Knife Sheath
I love my Benchmade Fixed Griptilian, and I used to love the sheath.
I modded it to snap at the guard, but the cheap nylon where the belt loop attaches is sewn on one side only, and tore out after only four trips into the brush.
Kydex is nice and all, but I've had a penchant for those european style leather friction holsters that go past the guard. This obviously wasn't the best knife to do something like this on, but how do you know what you can do unless you try it?
Step 1: Designing the Sheath
Because I already knew what style I was going for, I was able to set up the sheath for a bend along the spine of the knife. There are lots of different styles of sheathes, and you're making your own from scratch so don't feel boxed in to a certain sheath type. You're going to prototype on paper first, so let your imagination wander a bit. Do something new and different :)
First, take some masking or painters tape and tape up the cutting edge of your blade, and add some extra on the tip. You're going to be manipulating this knife and moving it around in an insecure sheath, and not getting cut is so much fun you should do it every day.
On a large piece of craft paper (I just used large drawing paper), I traced the outline of the knife with the spine (where the bend will be) touching the paper, then rolled it to either side, tracing it on each side.
When tracing, be mindful of where you're going to stitch or clamp. It's always a good idea to leave extra! It's easy to remove leather, but it's hard to add!
Next I set up the attached belt loop (because I wanted it to be one piece) by making a wide cut in the direction of the loop, then adjusted it until the angle and length were correct and trimmed the excess.
NOTE: Keep in mind the width of the belts you're going to be using, how high or low you want the knife to sit on your waist, and how much you want it to swing or not swing when it's attached (how tightly it will fit to the belt, and how wide the loop is)
Once the paper sheath is free from the sheet of craft paper, try folding it around the knife to make sure it fits correctly and the lines are where you want them to be.
When it's paper it's easy to get the right/left handedness of it mixed up, so be sure to mark which side of the template is for the inside or outside when it's facing up on the leather you're tracing it onto. This way you don't accidentally cut it with the pretty side facing in.
NOTE: The above only applies for designs that are NOT symmetrical.
I added a strap across the front that will look pretty and double as a small of back belt loop. It can be a separate piece so I'm not going to include it on the main piece.
Step 2: Cut Out, Soak, Form, Clamp!
Unfold your paper template over your leather, and cut it out.
Soak the leather piece in hot water until it becomes much more flexible, and then wrap it around your plastic-wrapped knife.
You can use a straight-edge to make sure your fold is in the right place before you really start putting pressure on it.
Once everything looks like it is where it's supposed to be, add your clamps.
I used clothespins because they were available, and while they worked well, they left much to be desired.
Ideally you would use clamps that distribute the pressure evenly so the leather doesn't deform or get pressure marks from the clamps. Keep in mind, though, most of those pressure marks can come out with some hot water and massaging.
If you're doing a friction retention sheath, make sure you clamp beyond the retention point.
Step 3: Let It Dry!
I left this for about 5 hours before removing the clothespins, and was amazed how well the leather molded and held its shape.
I had expected I would need to stitch the sheath closed before the friction retention would work, but it's already at the exact tension I want it to be!
Step 4: Trim and Stitch!
Try to mark out your stitches as evenly as you can. There are a variety of leather spacer tools that you can buy to mark your sewing holes perfectly evenly, but a little effort will bypass that additional purchase. Make sure you mark on the side you're going to tie the knot on. Your final stitch will be to pull the extra waxed thread from the other side to the side your punching through to tie the knot.
Once all your stitching points are marked, work out the sewing order.
Closing the flap that covers the blade may make it hard to get to sew the belt loop (because you need easy access to both sides of the leather), while the outside stitching can be done last and doesn't block any other areas. Keep in mind where you're layering pieces on top of each other, and which pieces need to be joined together before joining the sheath.
With sewing order determined, you can start sewing. If possible glue pieces together to prevent movement while stitching. Depending on the thickness of your work, you may need a lot of force to push your awl through the layers of leather. If this is the case, protect your awl's tip by placing it over something stiff but still able to be penetrated by the awl, such as layered cardboard. I did it on the carpet, and I could feel my needle go through the carpet and pad, and into the concrete. Afterward, I could tell there was a slight bur on the tip that will have to be repaired with an emery board or sharpening stone.
Leave lots of extra on the other side of the work piece. I wound up leaving about a quarter the length extra because I had trouble tying the first few knots because there wasn't enough to tie easily.
Once everything was tied up, I used a box cutter to trim the excess. Be sure not to cut too close or too quickly. The leather should cut easily, and if there are too many layers, make multiple passes. You do NOT want to find yourself putting lots of effort into your cut because it's binding. If it's hard to do, something's wrong. It's hard to put leather back on, and easy to take it off. Take your time.
Step 5: Finishing
When you're sure your stitches are where you want them to be, you can use a little super glue on the knots (make sure they're tight!) and after a while, it will harden very well and keep everything where you want it. Then trim the excess thread. If your thread is white like mine, and you don't want it to be, I found dry erase marker worked best to color the waxed thread evenly and didn't seem to rub off. A little super glue after coloring will protect the color.
Sand your edges to make them as even as possible, and to open up the leather (if previously sealed) to accept the glue.
Normally, you'd use dye and leather cement to make things pretty, but I want this to be done now and cheaply so I can start on the next one, so sharpie and super glue everywhere!
I used a sharpie to color the exposed edge of the leather, then put on multiple layers of super glue (it takes a bit to dry in between, blow on it to make it dry faster, but don't inhale too much of the fumes or you'll get a headache).
Once sealed with super glue it'll look shiny, sand it with some 220 or finer grit sandpaper to dull it, and smooth it. Once it's smooth, hold it to the light looking for gaps in the glue and apply more there and sand when it dries. You want to seal the untreated leather against moisture.
When it's fully sealed and sanded, put a LITTLE acetone (if you used super glue) on a rag or paper towel (not a cotton ball or something that will leave debris on the sheath) and rub over it gently. Don't use too much because acetone will dissolve the glue and may discolor the dye on your leather (if it is dyed).
Step 6: Enjoy!
Enjoy your custom handmade sheath, and start planning out your next one!