Would armour made of spider silk work?

Question

Would it be possible to use spider silk for armour, instead of metal?

I am not worried about how to obtain the silk. I know that spiders are not domesticable and that they are too aggressive to each others so that they cannot be lumped together like bees. (I can handwave all that; my spiders are just of a different species, unknown to us.)

But would it offer similar protection against pre-gun powder weapons? Would it be able to resist the thrust of a spear or an arrow, or the cut of a sword or knife (all made of common materials such as steel)? And how should it be used, lax, as a kind of shirt like chain mail, or would it be better to use it tense, as in shields? Would there be a particularly good way to weave the material for either use? And would it be transparent enough for use as a visor?

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Thanks for the input so far.

A few things to notice:

• these people's technology, spiderculture aside, is roughly Earth's 14th century, so no Kevlar or other things demanding sophisticated chemistry. They can stretch the silk in order to reduce its extensibility, and it seems a good idea;
• they have no magic - they just happen to know a peculiar species of spider that can be domesticated (I don't need to explain why they are domesticable, they just are: Arachnia mirabilis, if you so wish);
• the issue is important because it should have given them military superiority against their enemies: better or similarly armoured infantry and cavalry with much greater ability to maneuver, thanks to reduction in weight, and armored sailors who can survive a shipwreck or a fall into the sea;
• my biggest concern is, if a soldier using such armour is hit by an arrow, would the arrow be stopped, or would it penetrate skin and flesh, carrying the silk together with it?

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Edit to explain why I don't think this is a duplicate:

That question is about mixing spider silk, keratin, and bone, to make armour. It supposes high technology, and its emphasis is on how to produce the armour material. My question is about spider silk, in a middle age setting, and the emphasis is on how to use the armour, and what it would be able to resist.

Answer 1

Cloth armor - specifically, linen armor - was a thing, historically. It was used, tested, and could be quite effective. it was lighter and, reportedly, more comfortable and/or maneuverable than other armors, for the tradeoff of being also not quite as effective. Silk was more expensive, so there don't seem to be as much evidence for cloth armor made of silk - but on a cloth-for-cloth basis, there doesn't seem to be any reason the same kinds of techniques shouldn't work, if you have enough of the silk to make it cost-effective.

A Greek style armor called linothorax was reconstructed through using a lamination technique to transform linen cloth into stiff plates - essentially using multiple layers brushed with glue. This reconstruction was tested against arrows, and a thickness of 12mm supposedly would have been enough against any arrow the wearer was likely to encounter for about a 400 year period (see link for original tests).

Quilted Gambesons or Padded Jacks were sometimes used under other armor, but also sometimes used as a standalone. they were made from many layers, perhaps as many as thirty, of cloth quilted together - Linen was a popular choice as it was available, lightweight, and fairly effective (though some incorporated cotton, wool, or leather for extra effect). Testing of a reconstruction showed that such all-linen gambesons were an imperfect, but effective armor - the armor blunted some shots and reduced others to what would be lesser injuries from many of the arrows (though not all, depending on the arrowheads, see link for original tests), and proved somewhat effective even against spear or sword.

As for silk, I've vaguely heard of quilted silk armor being used (like the gambeson, up to thirty layers quilted together) among the Japanese and Koreans historically - and even in modern times, since this kind of armor may be bullet resistant, depending on caliber. However, I don't have nearly as good historical references, or testing information, about this kind of armor. Xplodotron's previous answer mentioned the use of a layer of silk and air pressure could deflect most (70%) of the arrows fired at it, which seems to indicate silk resists penetration pretty well as a single layer (compared to linen which I could not find used as a single layer for armor), and suggest that a layered silk version, like the linen armors, would be quite effective.

So your basic choices might be quilted silk, using many layers to resist the penetration of arrows, spears or swords; or else a laminated silk, where the layers are stiffened with glue to form a kind of plate mail. The first is going to be a lot more flexible, and probably easier to make, adjust, or work with, with the tradeoff of somewhat lower protection (arrows and the like might still penetrate, but much less than without the armor - and it does much less to protect against blunt force). The second is a lot more tricky to work with (and you'd need the glue, though a relatively low quality rabbit glue was well used) - and each piece of each armor must be separately laminated and fitted (it will resist tools as much as weapons), making it more labor-intensive but also a better protection.

Of course, since you plan for an abundance of spider-silk, maybe you could use both, either/or depending on the warrior and their role in fighting, or a hybrid with reinforced plates over vital areas, but quilted armor over other areas for more maneuverability.

I don't think you could make a visor out of it - you might get enough transparency to get away with a single sheer or gauzy layer, but you would get very little protection from it, and it would reduce visibility. At most you might deny your opponents an aiming point (faceless! aah!) if you used that single layer in conjunction with other silk armor, like a laminated silk helmet that does cover the rest of the face, but still allows openings like knights' helmets had for seeing through and such.

Answer 2

Silk is a flexible material, so it simply could not replace metal in rigid armors like plate, nor in shields. You would have a soft, flexible armor more akin to chain mail, but much lighter.

However, silk is a tough material that resists cutting and tearing, and in fact in real life silk has indeed been used as armor, sometimes standalone but most often as an additional layer under something stiffer, such as leather or plate; the Mongols, for instance, often used silk as a backing for leather and metal scale and lamellar armors.

The advantages of silk as an armor are that it is lightweight, flexible, and breathable, while still providing reasonable protection against cuts and thrusts (it's obviously not going to do much against blunt force). Spider silk would only enhance all of these properties.

There's literally dozens of different ways to employ your silk as armor: A layer or two underneath plate armor can improve that armor's defense against piercing attacks such as spears and arrows; using it as a backing for scale or lamellar armors can make them more lightweight and more flexible, with little sacrificed in the way of protection; on its own, a few layers of spider silk could even provide proof against an assassin's bullet!

Answer 3

Not only do you have to handwave the mass production of it, but you have to handwave how the armor is produced. But if you do handwave these things then yes, it may work well, although handwaving the production will be not so easy (think secret monk technologies of remaining former alien space race technologies).

Just from wiki: Spider silk

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The overall strength is good enough.

• Dragline silk's tensile strength is comparable to that of high-grade alloy steel (450 - 1970 MPa) and about half as strong as aramid filaments, such as Twaron or Kevlar (3000 MPa).

But what is good for spiders is not so good for armor. I mean the extensibity of silk. In tech there are known solutions for such things - there are pre-stretch building material.

That way if you stretch it and find a way to wind them together - you may have a product with different rigidity, from steel hard to rubber like stuff, as you choose.

And reasonable steel strength with less mass.

• Consisting of mainly protein, silks are about a sixth of the density of steel (1.31 g/cm3).

The easiest way to prestretch it is to make cloth, stretch it and impregnate it with resin. You may loose some strength and other advantages, but it will better redistribute the pressure over the penetration area and will not bend into the chest at the place it gets hit.

But actually the bending ability can be used for better protection, in terms of stopping something.

Without resin, but with a magic-smart weave process, you may make armor as strong as steel, as hard as steel and with less weight.

So any Kevlar product and fiber glass, any carbon plastic - are good enough to show what may be done. Just the process of making these will be more tricky and the strength will be something between fiberglass and kevlar.

P.S.
As Vakus Drake noticed there is Darwin's bark spider, which silk is at least twice stronger than usual in spiders community. Some properties are investigated in this paper, you may wish to read. And I find this quote from that paper hopeful for those who wish even more:

• Thus we have available some 200.000+ unique silks that may cover an amazing breadth of material properties. To date, however, silks from only a few tens of species have been characterized, most chosen haphazardly as model organisms (Nephila) or simply from researchers' backyards.

Answer 4

If you allow more handwaving into your story...

Kevlar is a synthetic fiber. It is similar to spider silk in some ways, though Kevlar is more appropriate for armor not only due to availability, but also due to its mechanical properties. If you could get enough web to make a vest out of it, with technology similar to that used to make a Kevlar vest, you'd have a somewhat bullet-proof, somewhat slash-resistant (slightly better than nothing) but it probably wouldn't protect you against piercing nor crushing weapons on its own. Notice that Kevlar is somewhat like that too... It is made to protect you from bullets, but it is not rated for piece protection (i.e.: it is not stab-proof) for example.

TL;DR you could make a Kevlar-like vest with it, but it wouldn't be as good as Kevlar, and you have to do a lot of handwaving to make that feasible.

And it would not be transparent. Look at this vest made of spider silk, as seen in Wikipedia:

All in all, this could be an addition to protective clothing for people who work with dangerous materials or environments, but armed forces and police would probably fare better with other protective materials. And the people of your world would have to lack leather, metals, synthethic fibers or the technology to work with these to go for spider silk armor.

Answer 5

Billowing silk cloaks were used by horse-riding samurai to block most (not all) arrows. It's called a horo. See here: https://www.youtube.com/watch?v=8B_6BU7SYf8

Some horo had light framework (like a hoop-dress) to keep it billowed. To the extent that a shield is considered "armor," one could think of the horo as a silk shield you wear on your back.

I understand the OP uses the word "armour" in the question, but in a broader sense the horo is something that is worn which provides "protection" to samurai and messengers, allowing them to survive what would otherwise be fatal hits from attacking archers.

Answer 6

Let me introduce you to the golden silk orb-weaver, this spiders silk is known for its tensile strength. It is indeed so strong that if it was as thick as a pencil, it could stop a jet! In 2012 a cape was even mad using this material and if its molecular compound can be determined, it will easily replace kevlar.

Answer 7

There is already a historic precedent: Genghis Khan had his soldiers wear silk armor beneath their normal protection. Anecdotally, Genghis Khan's soldiers took arrows that penetrated the traditional armor, and should have killed them, but were prevented from doing harm by the silk, lending to stories of the soldier's invincibility.

Answer 8

This is actually being attempted, although an regular spider's silk would not stop much there are actually ways of making it work, i must point out that at some point in history even paper was used to make armor and it was effective (100% sure about that just google) this would work by adding several layers of it making it a really good armor (same protection as chainmail) but would bot last a lot after a few blows blocked it would be wrecked. Nowadays, there is an on-going attempted to create an real life a bulletproof vest made from spiderweb as their tensile strength goes toe to toe with steal without being as heavy (100% sure about that just google), and it does sound to me that if there was a population who lived closely with similar spider could have picked up some sort of way to make the armor you spoke of.