Making a Leather Bottle Using the “X1” Hardening Technique

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After completing my study on developing the optimal hardening method, it was time to begin developing new methods and pieces, taking advantage of the properties this new material offered. Among the first articles I tried making were flasks and bottles; I was curious as to not only the strength but water resistance of the leather. Following is the build process for the fifth hardened bottle I made. Finished photos first, then the details.

One of the first design problems I found when approaching this project, was the fact that the hardened leather wouldn’t allow for many options for adding decoration. I’ve since learned that all adhesives fail during the hardening process, and not much likes to stick to stearic acid-hardened leather. For this reason, I chose to create the bottle first, and then a “mask” on top for aesthetics.

The first step is designing the bottle. I never use pre-made patterns or templates if I can help it, preferring to draw my own from scratch. The design process is just as much fun as the build, in my opinion.

The completed pattern is transferred to tracing paper, then to cased (dampened) leather with a stylus. I used 8-9 oz vegetable tanned cowhide for the bottle itself.

Pieces for both sides of the bottle are traced out. The rear piece needs only the outermost line, while the front piece needs the two stitch lines traced as well. Those are then marked for stitch holes with an overstitch wheel.

The two bottle halves are cut out, with about a 1/4 inch margin to allow wiggle room when it comes time to clean up the edge.

The flesh side of each half are cased with water, and the innermost stitch line traced onto both.

This line is used as a guide when applying cement. I use Barge, and a glue spreader is very helpful.

Once the cement is ready, the two halves are pressed together, and the glued area gently tapped with a light, smooth-faced hammer to set the bond.

This is the time to apply dye if desired. Anticipating the significant darkening of the hardening process, I chose to only airbrush a dark border on this piece with a blend of mahogany, red, and black Fiebing’s leather dye.

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The bottle is then stitched together. I can’t recommend The Art of Hand Sewing Leather by Al Stohlman strongly enough; my stitching quality improved vastly after reading and practicing for a bit.

Stitching completed. I used coad or “hand wax”, a mix of pine rosin and beeswax, on the thread to improve waterproofing. It’s the shiny white ball in the photo above, and quite easy to make at home. This recipe was 2:1 rosin to wax. These are melted in a double boiler, then poured into a bucket of cool water and pulled like taffy until hard. The result is a material that’s normally very firm, but becomes sticky very fast with a little friction and heat. This also helps set the stitches, though sewing with it takes practice. The thread will bind up if you don’t keep it moving fast enough; each stitch needs to be made in as continuous and fluid a motion as possible.

The leather is then soaked in room temperature water for about ten minutes, or shortly after it stops bubbling.

The bottle is then blotted free of excess water, and packed with pearled barley to give it shape. Some folks prefer other packing media such as sand or popcorn. Still others recommend forming the bottle shape using molds instead of packing, and I’ll likely try that method soon as well.

A bit of barley is added at a time, and packed into the bottle as firmly as possible.

Once fully packed, the stick is left in to maintain the neck shape, and the bottle left for a couple of days to dry.

Once dried, the barley is removed from the bottle. I do this with a piece of coat-hanger wire bent into a hook, with a sharpened tip. A headlamp also helps. This is definitely one of the drawbacks to this method, and takes a bit of time to be sure you’ve gotten every grain.

The headlamp comes in handy for peeking down into the bottle for clumps of grain still sticking.

With the barley removed, the bottle is taken to the belt sander to clean up the edges and remove excess leather.

The bottle is now shaped, dried, cleaned up, and ready for hardening.

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I now apply my “X1” hardening technique. The bottle is first preheated to 150 degrees Fahrenheit, and immersed in a pot of molten stearic acid that’s been cooled to the same. I made a quick ladle out of aluminum foil, and used it to fill the bottle with stearic acid as well, to prevent floating and ensure proper saturation of the leather.

Although thick, the leather took only fifteen seconds or so to stop bubbling and indicate it was fully saturated. Preheating the leather is vital to success here. The temperature is then raised.

After about 30 seconds at 200 degrees, the leather should have gone through thermal changes needed to supply the heat-hardening effect of the method.

The bottle is removed, and I used the barley-packing stick again, to allow the bottle to cool and maintain neck shape.

Edge finishing for this material requires edge beveling followed by sanding up to about 5,000 grit. No burnishing compound is used. The hardened leather takes on a very high gloss by itself.

The bottle itself is now completed, and work begins on the bottle stopper, carrying cord, and mask.

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I used amboyna burl for the stopper, an exotic wood with beautiful grain and color.

Shaping was done initially with the belt sander, and then hand sanding when approaching the final shape.

I made a special batch of varnish for the stopper. The recipe used four ounces white copal, four ounces propolis, and eight ounces blonde shellac flakes dissolved in a liter of denatured alcohol. The solution was given a shake twice a day for two weeks, then strained through cheesecloth. The resulting varnish has a rich, reddish brown color, a lovely aroma of honey and wood, and a very high and beautiful gloss.

The stopper was sanded to 600 grit, and given three dips in the varnish. It turned out wonderfully. The varnish does take quite a long time to cure before fully hardened; in this case, about a week and a half.

I used three colors of pure silk habotai cord, and made a six strand braid for the bottle carrying cord. The ends were capped with brass finials.

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Mask design began by creating a mock-up using craft foam. This allowed me to choose good placement of the carnelian cabochons.

Satisfied with the mask design, I cut three out of 4-5 oz vegetable tanned cowhide. The bottle was wrapped in plastic wrap, the water-soaked mask applied, and together placed in a plastic bag and vacuum sealed shut. While this doesn’t allow the leather to dry, if left overnight it will hold the bottle shape and can finish drying once removed.

My kind father found for me an old, crocodile skin journal cover. I chose a piece from this for the bottle front, cut it out, deglazed with 90:10 acetone and ethanol, dyed, and finished again with tan-kote.

Now that the bottle is fully hardened, it makes a good surface to provide support when tracing and cutting. Just be very careful not to cut through the leather and into the bottle!

I’d originally planned to only bevel the inside of the cut for the crocodile inlay, but later chose to cut this out entirely, since I didn’t care for the alignment with the first method, and I’d have the second mask layer underneath to attach to anyway.

The area for the crocodile inlay is cut out, as well as areas for the carnelian cabochons. The mask is dyed, and ready for a bit of tooling.

The pattern for tooling is completed, and carnelian and crocodile attached to the lower mask layer with Barge. I also added a border of dark dye around the crocodile, to help hide my sins when the top layer is added.

The tooling pattern is transferred to the cased mask with tracing paper and stylus. These lines are then cut with a swivel knife, stitch holes around the cabochons marked with overstitch wheel, and inner edges around the inlay and stones dyed and burnished.

The mask is anchored to a tooling slab with painter’s tape, and outer edges of the tooled lines beveled.

I chose to add the 24 karat gold leaf at this time. Gold size (adhesive) was carefully brushed onto the raised areas, dried, then gold leaf applied and excess brushed off.

Gold leaf has been applied to the mask. Applying it at this stage turned out to be a mistake, and much of the gold rubbed off along the build. In retrospect, I’ll definitely add gold leaf as a final step.

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Preparing to glue the upper and lower layers of the front mask together. Barge was used for leather on leather, and Krazy Glue gel was used for leather on stone. Just prior to joining the layers, I skived the flesh side of the upper mask layer, around the edges of stone and crocodile. I then moistened the stone bezels thoroughly, and used a burnishing tool to shape them to the stones.

This process was completed carefully, and in many stages. Barge was applied to sections of leather, upper and lower. When dry, Krazy Glue was applied to the edge of the stone, and the mask layers pressed together.

Once the mask layers are glued, 0.6 mm thread was stitched around the cabochon edges.

Around this time, I also finished braiding the carrying cord, and after adding finials, gave them and the rest of the brass hardware used, a coat of 24k gold.

To find the final, proper shape for the attachment “wings”, the bottle outline and stitch lines were traced.

The mask wings were then lightly cased with water, and the bottle wing outlines traced on with a stylus.

The final wing shapes were cut on the mask. Edges were beveled and sanded flush, then hand sanded to 1500 grit, dyed, and burnished with gum tragacanth followed by beeswax.

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The rear mask was made at this time. A single layer of leather was used here, and a much simpler design.

The rear mask was temporarily attached, and the tracing paper pattern over that. A stylus transferred it to the mask.

Again, the pattern was cut with a swivel knife, cased, and edges beveled down. This time I found a modeling spoon much easier than bevelers and mallet.

At this point it was time to decide how to create the attachment point where I planned for the two cord ends to meet the bottom of the bottle. This took a bit of thinking, and I ended up using one part of a decorative Chicago screw, and a brass hanger. I found a small bolt that threaded into the hanger, and filed the head down until it threaded into the Chicago screw.

This gave me exactly what I needed; an elegant attachment point, and a piece of hardware I couldn’t find elsewhere.

The two cord ends were attached through the hanger hole using thick thread.

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To attach the upper mask wings, holes were cut with a die and arbor press. I agonized for weeks on how best to approach this. I couldn’t find any appropriate hardware for this attachment either. The three mask layers plus the bottle were about 13 mm; I found threaded brass gaskets, but none that long. I didn’t want to rely solely on adhesives for a structural part like this, either.

The second gift my father brought to this project, was the brilliant solution I ended up using. Short sections of 1/2 inch copper pipe were first annealed (softened) by heating to medium red with a propane torch, then quenching in water.

The annealed copper is very easy to work by hammering with light hand tools.

These were then inserted through the holes cut in the mask layers and bottle.

Flaring out the copper tubes began with a plumb bob on one end and a dowel on the other. Tapping gently and changing sides frequently, I was satisfied once it was clear the edges could no longer curl inwards.

Two ball-peen hammers, one on each side, were used to finish flattening the tubes.

The result was very satisfying and met all the requirements I had for this step. The copper was then given gold leaf as the rest of the hardware.

The only steps remaining at this point were to touch up the gold leaf and small dye spots, and add a finish to the mask. For the final application of gold, talcum powder as used on areas of the mask gold wasn’t wanted. This definitely helped in maintaining a clean final appearance.

Tan-kote was carefully applied with a brush to non-gilded leather. The varnish used on the wooden stopper was applied over the gold to protect it. Of all finishes I tried, the copal and propolis varnish was the only one that seemed to retain the rich luster of gold.