What would be the effects of copious amounts of spider silk be on a highly militaristic country? The country is somewhere between renaissance and industrial as far as development, and has had access to the silk for ~400 years, since the country first originated.

Some of the most impressive strands of spider silk on earth exceed 5x the strength of steel, ounce for ounce. However, as this is world building, my spiders are, near inevitably, the slightly magical kind, and so can exceed this limit if desired/necessary.

NOTE : The spiders are not friendly to humanity in any way, and must be carefully handled to gather the silk, however, centuries of the market being open have allowed there to be plenty available.

What would be the military applications of possessing a renewable source of spider silk?

The silk can match, and somewhat exceed, 5x the strength of steel per gram, and the strands can be as long as necessary. The silk can be braided together to attain any desired width.

My primary thoughts involve a light weight and effective body armour, a method of creating a perimeter (something like several lines of spider silk wrapped around a staked out boundary, each strand a hands height above the other or so), and possibly allow for more effective siege engines? Would an increase in the strength of the "rope" in, say, a trebuchet allow for a more effective range or mass of the trebuchets ammunition?

  • $\begingroup$ There are several properties including tensile strength and toughness, that have different values. See chart. Regular silk is about half of spider silk, so I expect the simple answer is "same as without spiders, but twice as good". $\endgroup$
    – JDługosz
    Apr 4, 2015 at 9:52
  • $\begingroup$ the wall wont work, because even with magical silk the weakest link is the stakes probably, unless your stakes are made of silk, or the wall goes 500 meters underground :o $\endgroup$
    – gia
    Apr 4, 2015 at 18:22
  • $\begingroup$ Thank you very much for the chart JDlugosz, and forgive me gia, but I don't quite understand what you're point is. I'm aware that the stakes would be a weak point, but I'm thinking that if you were to even get the 3.5 meter sticks a meter into the ground( admitedly, not an easy task, especially considering soil types..), they would be fairly feasible. They wouldn't at all replace stone bulwark walls, that wasn't the idea I was attempting to convey, but more as a chance for troops in the field to have at least an extra minute or two in case of a night raid. $\endgroup$ Apr 5, 2015 at 5:31

3 Answers 3


Walls are a terrible use of this magically amazing substance. Walls need to be strong(ish) and heavy and easily constructable. Dirt is all of these things and is available everywhere. Stone is more of these things and available nearly everywhere.

Step one: Replace all your fabrics with spider silk and cut applicable equipment weight by 80% or more.

Step two: Build really powerful catapults. Wound spider silk is very strong because it's quite stiff and very stretchy(compared to steel or carbon fiber). So just build a giant slingshot. Or a malgonel. You have a thing which will store an absurd amount of energy compared to sinew or any other fiber available.

Step three: Armor! You have a strong very tough fiber. Because it's stretchy you probably don't want to just weave a jacket out of it(but you could! And it would probably work great at least against projectiles) but its real use would be in a composite material. Steel is hard to make and expensive. Quartz is the second most common material in the earth's crust, so you have lots of that lying around. Take small bits of it and embed them in a silk matrix. It's very hard (mohs 7, steel is a mohs 5ish) so it'll 'catch' arrowheads and sword blades, keeping them from applying their cutting ability to the silk. Instead of using a sharp edge to cut the silk, the quartz inclusions will have to be pushed through the silk matrix, making all weapons only as sharp as your average quartzlump. Congratulations! The arrow is obsolete. The sword becomes a silly hammer. (Wear a regular helmet though. Or a big fluffy shock absorbing helmet. you know. Something.)

Now: for the hammers. They're very heavy. Dodge them. Maybe work some kind of stiffening rods or something into your armor? That would dissipate the energy of an impact more evenly. Rib bones are about the right shape and lighter than wood or metal per unit strength, but they only come in a few shapes.

I just realized that with the ribs and the silk 'skin' and the quartz lumps I've been building an ankylosaurus.


Mmm, a substance both lighter and 5x stronger than steel? Military applications seem obvious, no?

It'll work great .. that is ... until the enemy realizes spider silk is.. um.. flammable.

Then, I'm guessing you'd have lots of cobwebs everywhere?

Perhaps you can bog the enemy down in silkwebs and light them up?

  • $\begingroup$ Thank you very much good sir/madam! The importance of spider silks weakness to heat is very disadvantageous in most any case. However, and I suppose this is my fault for not being more clear, I apologize, the military is not dealing with a group of other people, but rather, a mob of monsters, none of which have the intelligence nor capability to obtain or utilize fire. From what poking around I've done, the proteins in spider silk start to denature when exposed to too high a heat. This could be a good source of conflict once all the monsters are gone though... $\endgroup$ Apr 5, 2015 at 5:32
  • 2
    $\begingroup$ Spider silk is not especially flammable (no more than things like human hair). Cobwebs are considered a potential fire hazard because they can trap dust. $\endgroup$
    – zeta
    Apr 16, 2015 at 15:19

I would say even with large amounts of silk available, you are talking about a LOT of silk to make a wall' around an encampment. The Romans made encampments every night they were on the March buy digging a trench and piling the dirt on the inside to make a ditch and then a hill that would have to be climbed in an attack. the ditch and hills could be lined with stakes if an attack was felt to be likely.

I would say that the setting up the silk wall would take just as long as the ditch digging, so no real advantage there. The silk would also dramatically reduce visibility. it would be harder for lookouts to spot trouble. So there would have to be towers to peer over the 'walls'. These towers would be stationary so might miss small or individual attacks.

It would not be very portable. It would be very troublesome for any kind of encampment because it would need possibly 100,s of pounds of fabric per 50-100ft? of wall. Not to mention the need for the towers.

Fabric of any kind will also have to deal with the weather, a long term emplacement will constantly have to be checking on the quality of the walls, looking for wear and rot and then having someone replace these sections. (which will leave a weaker point in the wall, since the weave will not overlap any more and only have the 'stitches' holding it.

Now if it's more of a 'net' or 'web' like fence you have a lot more chance of making it useful against an attacking foe that tries to get you physically (as opposed to long range weapons). However I would still use it as an extra defense added to others and not the primary defense, since it still has many of the same issues of weight, wear and rot.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .