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I am always looking for ways to improve my slingshots. One way is to make the pouch out of an exceptionally strong leather so that it can be made as light as possible. Saving pouch weight can make a substantial difference in velocity, particularly when shooting light projectiles.

I did some research and asked some people I know who are in the leather trade for suggestions as to what kinds of leather would offer the highest tensile strength. I am still waiting for samples of falconry grade kangaroo leather, salmon leather and some other potentially superior leathers, but I am ready to publish some interesting test results for your reference and to stimulate new ideas.

My method was to take a strip slightly wider than 10 mm and to use a round hole punch to create a weak point of 10mm across. I incrementally applied pressure from a chain hoist till the leather failed. If the scale maxed out first (>30Kg), I would reduce the width with the round cutter to 3-5mm and retest, scaling up the break test tension proportionally.

Name: Upholstry leather
Animal: Bovine/ Cowhide
Split: top grain
Part of hide: believed to be bend
Tanning: believed to be vegetable tan, chrome re-tanned, aniline
Post treatment: None
Weight: 0.10g/cm²
Thickness: 1.25mm
Tensile strength: 22kg/cm width
Comments: Currently used on my Flatbands. Cheap and plentiful.

Name: Saddle leather
Animal: Bovine/ Cowhide
Split: top, buffed
Part of hide: back/side
Tanning: vegetable tan
Post treatment: saturated in oil based treatment
Weight: 0.15g/cm²
Thickness: 1.60mm
Tensile strength: 62 kg/cm width
Comments: Bought from a craft merchant for use in making tooled leather articles. Can be skived. Plentiful locally.

Name: Deer leather
Animal: Deer (wild cull)
Split: top
Part of hide: unknown
Tanning: Chromium
Post treatment: none
Weight: 0.05g/cm²
Thickness: 1.05mm
Tensile strength: 12.5kg/cm width
Comments: A little stronger and much lighter than upholstry leather. A reasonable choice if I want a lighter pouch. A bit too stretchy. Tendency to tear. Expensive.

Name: Suomi pressed leather
Animal: Bovine/ Cowhide
Split: believed top
Part of hide: unknown
Tanning: vegetable, pressed
Post treatment: saturated in oil based treatment
Weight: 0.28g/cm²
Thickness: 2.43mm
Tensile strength: 70kg/cm width
Comments: A very strong leather, but inflexible. Very hard to cut. Expensive.

Name: Lapp leather
Animal: Reindeer
Split: believed top
Part of hide: unknown
Tanning: Vegetable, traditional, pressed, buffed
Post treatment: saturated in oil based treatment
Weight: 0.20g/cm²
Thickness: 2.35mm
Tensile strength: 66kg/cm width
Comments: A very strong leather, but inflexible. Almost impossible to cut; had to be cut on a band-saw. Very expensive. Special order.

For now, I will continue to use the upholstry leather.


Flower Plant Terrestrial plant Water Grass

whipcrackdeadbunny
Sep 14 2010 06:16 AM

I can't find a decent supply of leather anywhere! It's so vexing!
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Did you try leather sample books?


Carnivore Fawn Dog breed Grass Terrestrial animal

ZDP-189
Sep 16 2010 12:32 AM

Thanks for your excellent work.

62 kg/cm width?

A photo would be worth 1,000 words.

Taking thickness into account we calculate 38.75 kg/cm/mm width (dividing 62 by 1.6).
Yes that's why I gave the width as well, but seeing as I don't plan to skive the leather, and the data would not be valid proportionally to the thickness if skived, the practical units are kg/cm. Sorry about the use of metrics. For my first few months here I dutifully converted all the measurements into American (Imperial) units, but I have trouble doing science in anything but metric units.

I also gave the weight per surface area, which is how leather merchants grade leather thickness, so you could use it to calculate the weight of a pouch that could hold a given tension.

I can't find a decent supply of leather anywhere! It's so vexing!
Smile Food Ball Font Symmetry
Did you try leather sample books?
That's a good idea for Sam, but Seeing as I will have to make a whole bunch of pouches for Pete, I need a whole sides, or at least a big chunk of one.

Great stuff, as always; have you tried hammering some flex into the Reindeer hide? or doubling-up the Deer leather?
No, I don't want to double leather or pound on it for these experiments as I want consistent results. It's a good idea though!


Hairstyle Eyebrow Eye Neck Jaw

mr.joel
Oct 27 2011 01:51 PM

Wet scrape brain tanned deer hide(done right) is the strongest possible leather (that's flexible) that I know of in deer like animal leather.
 
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