Medieval Glue

A couple of weeks ago we published an article on fletching glues including superglue, rubber based glue and fletching tape. But how did our archer ancestors get their feathers to stay stuck to their wooden or reed shafts? Its not like they could jump over to B&Q or give Merlin a call. For the purposes of this article we're going to focus on the Mongols who are arguably the greatest archery nation ever to have crushed their enemies, seen those enemies driven before them, and heard the lamentation of their women!

The Mongols were an East Asian nomadic people from the Central Asian steppes. Originally pastoral nomads, they were renowned for their unparalleled horse-mounted archery so we think they can be considered a good focus for our article. Mongol arrows were fletched with animal‑based glues, and the choice wasn’t random. They were very specific in what they needed from their glue. It needed to survive extreme climates, high draw weights*, the brutal vibration profile of composite bows and be available on the resource bare steppe. Historians, practical archaeologists, and surviving steppe traditions all agree on the below so its probably as definitive as we're going to get. Lets take a sniff of these glues and see where it takes us...

Collaborate in making some traditional glue? ... Think I'll pass if thats ok.

Hide Glue (Collagen): This was the primary adhesive for attaching feathers to shafts. The glue was strong but flexible which is ideal for the acceleration of a composite bow which, given their bows design, can get up to 200 feet/sec. Its been argued that 240ft/s was potentially feasible. For reference, this is a speed that is approaching modern recurve performances with performance arrows. The glue was easy to make given that its made from boiled animal skins, sinew, or connective tissue. The glue could be undone using heat and moisture which is useful for repairs on campaign where no workshop would be available. And finally this sort of glue works well on wooden or reed shafts, something that would have been a fundamental requirement for a horde dependent on woodies ... there's few carbons or ali's on the steppe! The hide glue behaves well in practice as it forms a bond that’s tough but not brittle, which is exactly what you want when the arrow is being launched from a bow that stores enormous energy relative to its size.
Mongol opinion: Ideal glue .. now on your knees or we shall destroy your cities and seed the ruins with salt.

Fish Glue (Isinglass): This sort of glue was used especially in wetter climates or for higher‑quality arrows. So why was this glue used in preference to hide glues? It mattered because of the improved water‑resistance over hide glues. Central Mongolia could be quite humid and persistently wet in some areas prompting the switch in glue to something better able to handle the conditions. A functional improvement over hide glue is that its very strong in thin films. That makes it perfect for placing a narrow thin glue line under a feather. As to whither the fish swim bladders were available on the steppe? The poor fish who were preferred (Sturgeon) were abundant in many Mongol regions which led to their goose being cooked .. or more accurately their ass (well, their swim bladders) getting boiled. Fish glue was prized across Eurasia for fine work due to its strength in thin layers — bowyers, fletchers, and even manuscript makers made use of it.
Mongol opinion: Excellent backup to hide glues .. now back on your knees or we shall destroy the other half of your cities we haven't got to yet.

Sinew Glue (a variant of hide glue): Sometimes used when the fletching was reinforced with a sinew wrap.This one wasn't used often but was used because it was extremely strong when combined with sinew binding. The glue gave excellent shock absorption and was ideal for arrows meant to survive repeated use. This glue was essentially a thicker, more fibrous version of hide glue.
Mongol opinion: As tough as my butt .. by the way, have you seen the pile of skulls outside your city gates?

Binding: So these very useful natural glues were used to restrain the fletchings but a practical people like the Mongols liked the belt and braces approach. Given their lives were on the line and dependent on their arrows, glue alone wasn’t the whole story. They had an extra step. Mongol arrows almost always used sinew or silk binding. Wrapped at the front and rear of the fletching, these materials prevented feather lift at high speeds and added durability in rain and humidity. This combination of animal glue AND the binding meant that Mongol arrows were reliable in harsh conditions. Not that this was a unique step. English fletchers did the exact same step with linen thread.

So to sum up, these glues worked for steppe warfare because they were resistant to sub‑zero winters and to desert heat. Their components could be easily acquired on long campaigns where there was little resupply (a feature of the war of rapid movement the Mongols preferred). Finally they were good at dealing with the high draw weights of the war bows. Animal glues excel in exactly the conditions faced by the mongols providing a performance that was strong, light, flexible, and excellent for field‑repairs ... Starting to think modern glues don't hold a burning brand to these puppies. Wonder if Merlin stock Sturgeon swim bladders?

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* Based on historical accounts and studies of composite reflex bows, the average draw weight of a Mongol war bow in the 13th century was likely ranged between 100 and 120 pounds (45–54 kg). Weapons belonging to elite warriors such as the Kheshig or specifically crafted bows could exceed 160 pounds (70+ kg).

Horsey image by 🌼Christel🌼 from Pixabay
Sturgeon image by Hans from Pixabay