I Guess I'm Stuck on You: The Secret History of Glue - Episode 18

00:00:00: I want you to think about something that's probably within arm reach right now.

00:00:05: Not something dramatic, not something that looks impressive Something so ordinary That You Might Genuinely Struggle To Remember The Last Time You Noticed It And That Is Glue.

00:00:16: Somewhere Near You In A Drawer In a Bag On A Shelf There is Probably Some Version Of It A Glue Stick From A School Bag A Roll of Tape in Kitchen Drawer A Tube Of Super Glue That Has Very Likely Stuck Itself Partially Shot.

00:00:29: And in the room you are sitting, whether can see it or not there's dozens of objects that're held together by adhesives.

00:00:35: The screen might be watching this on?

00:00:37: The soles your shoes!

00:00:39: The spine any book you could see…the furniture around you!

00:00:42: Glue is everywhere – It IS in most literal sense holding the world together...and IT'S THE MOST OVERLOOKED TECHNOLOGY IN HUMAN HISTORY.

00:00:52: We tell a story about civilization through loud inventions The wheel, fire the printing press steam engines computers.

00:01:00: Things that made dramatic noise that caused visible change.

00:01:03: That could be pointed to and said there!

00:01:06: That is when everything shifted.

00:01:08: Glue made no noise.

00:01:10: It helped things quietly.

00:01:11: it enabled every other invention by making composite structures possible By allowing different materials together By joining small to large soft hard lightweight.

00:01:23: And here is the fact that I think should reframe the entire story of human intelligence.

00:01:27: The first creature to make glue was not Homo sapiens, it was a Neanderthal!

00:01:33: Two hundred thousand years ago before our species had fully developed Before we'd arrived in Europe.

00:01:38: before any other things We credit out species with inventing and neanderthals somewhere In what now Italy figured how to heat birch bark To a precise temperature to extract a sticky black tar and used that tar to fix a stone blade into wooden handle.

00:01:54: That is the oldest known synthetic material in human history.

00:01:57: Older than pottery, older then woven textile, older than almost everything we consider the hallmarks of human ingenuity.

00:02:04: And it was glue!

00:02:07: Hi I'm Alexandra.

00:02:08: Welcome To The Hidden Life Of Things Everyday History.

00:02:11: For Anyone Who's Ever Looked At Something Super Ordinary And Wounded How Did This Actually Get Here?

00:02:17: Let me spend some time on that Neanderthal.

00:02:19: Because I think they deserve it, neanderthals are not the brutish club-swinging cavemen of popular imagination.

00:02:25: That image has been thoroughly dismantled by modern archaeology and genetics.

00:02:29: We now know that the other tales buried their dead possibly with flowers.

00:02:33: They used pigments possible for decoration .They made jewelry from eagle talons shells ,they interbred with homo sapiens if you have any Europeans or Asian ancestry roughly one to four percent Of your DNA is Neandertha.

00:02:45: They were not a different and lesser kind of creature, they are related kinds with complex cognitive lives social structures in cultural practices.

00:02:54: In two hundred thousand years ago there was making glue The evidence comes from archaeological sites in Italy & Germany Small lumps of dark sticky tar found on the Andertal tools.

00:03:05: Tar covered stone flakes clearly hafted meaning attached to handles.

00:03:09: but tar itself has been chemically analysed and identified as birch bark.

00:03:13: ta a substance produced by heating butch back to specific temperature range in the absence of oxygen.

00:03:19: Too hot and the bark burns, too cool and no tar is produced.

00:03:23: The target temperatures quite narrow roughly three hundred forty to three hundred seventy degrees Celsius.

00:03:29: Researchers at Leiden University spent years trying work out how Neanderthals could have achieved this without ceramics Without kilns that any control mechanisms would expect need.

00:03:39: They eventually found there are surprising simple method worked Roll birch bark tightly, place it in a hot embers with stone on top to limit oxygen and enough tar condenses onto the surface.

00:03:52: The simplest method requiring only fire and birch bar could work!

00:03:56: And more complex methods produced larger quantities.

00:03:59: What this means is extraordinary.

00:04:00: To produce birch-backed tar you need understand materials to know that specific tree produces these specific substance.

00:04:06: under those conditions You need plan ahead Gathering the birch bark before you need to tar, You need control of process managing heat and oxygen in a way that produces desired outcome rather than just burning bar.

00:04:19: And we have invented concept for halting first place.

00:04:23: The idea attaching handle with stone tool would make it significantly more effective.

00:04:28: Archaeologists use word hafting attached blade as marker of cognitive sophistication.

00:04:34: A stone blade on its own is useful but limited.

00:04:37: You have to hold it close your target, you risk cutting in hand.

00:04:40: Your force is limited what the grip can manage.

00:04:42: A half-tooled stone blade glued to a wooden shaft completely transforms whats possible.

00:04:47: You throw and use mechanical advantage of the handle.

00:04:51: You hunt from safer distance or apply more controlled directed force.

00:04:56: The leap from bare stone to half-ted tool Is one of most significant technological transitions in human prehistory And the material that made it possible, the substance that joined the stone to wood was a synthetic material deliberately manufactured by being not even our species.

00:05:12: Glue is no footnote in the story of human intelligence – It's evidence that intelligence itself….

00:05:17: The capacity to understand materials, plan processes and engineer composite solutions predates our species entirely!

00:05:25: Fast forward from the Italian hillsides of two hundred thousand years ago to the Valley Of The Kings around thirteen twenty-three BCE.

00:05:33: Tutankhamun, a boyfaro who died aged about nineteen in second census still debated by historians was buried with extraordinary care.

00:05:41: his tomb discovered by Howard Carter in nineteen twenty-two contained over five thousand objects furniture clothing jewellery chariots statues their accumulated material wealth of a royal household intended to accompany the king into eternity.

00:05:56: And when conservators at The Kyron Museum analyzed that furniture carefully, their inlaid wooden chests and chairs with decorative panels and shrines with gilded surfaces found animal glue – specifically a collagen-based adhesive prepared from animal hides and bones used to bond the veneer's surface to the wooden cores of the furniture.

00:06:17: Three thousand years old and the glue was still working, The veneers were still bonded.

00:06:21: Inlays in place!

00:06:23: The joints are still sound.

00:06:25: This is worth pausing on.

00:06:26: The furniture made for Tutankhamun's tomb is extraordinarily fine.

00:06:30: Thin sheets of rare wood or ivory, or glass paste laid over wooden cores creating surfaces a visual complexity and beauty that could not have been achieved in solid wood alone.

00:06:41: The veneer technique is completely dependent on adhesive.

00:06:43: without reliable glue the veneers peels splits and it's worse than useless.

00:06:48: With it you can take a piece of ordinary wood and cover with something extraordinary.

00:06:52: Creating surface looks feels like made from something rare throughout its entire depth.

00:06:58: The ancient Egyptians were using glue not just functionally, but artistically as a material that enabled the kind of beauty that didn't exist without it.

00:07:06: The luxury goods of the ancient world —the furniture and inlaid boxes—the composite boroughs laminated for multiple materials to combine the flecks of one material with the rigidity of another all those dependent on adhesives held reliably under conditions heat, humidity or stress.

00:07:22: The animal glue used in Egyptian furniture was made from collagen, the structural protein found in animal hides, hooves and bones.

00:07:29: When collagen is boiled in water it breaks down into gelatin allowed to cool.

00:07:33: that gelatin solidifies.

00:07:34: heated again it liquefies or can be applied as an adhesive.

00:07:38: when it cools and dries on the joint It forms a bond of remarkable strength.

00:07:41: This is essentially the same chemistry as the glue That Was Used In European Furniture Making until synthetic adhesives arrived in the twentieth century.

00:07:52: Thousands of years of glue making using this same fundamental material refined and improved across generations passed down through craft

00:07:59: traditions.".

00:08:00: Here is a connection that I find surprising, but think almost never gets made... The history of Glue Is the History Of The Written Word Not in the sense of ink or parchment.

00:08:11: those are different stories In the sense that physical survival of written knowledge across centuries depended on adhesive.

00:08:19: A book is not just paper and ink, a book is of binding.

00:08:23: The covers that protect the pages —the spine that holds the whole structure together— the signatures – the folded bundles-of-pages–that are sewn or glued into a coherent object….

00:08:33: …the leather or cloth covering over the boards that form the

00:08:35: cover.".

00:08:36: All this requires adhesive at multiple points!

00:08:39: Before the codex, the book format we still use with flat pages bound on one edge... ...the dominant form of written record in ancient world was the scroll Pyros or parchment sheets glued end-to-end to form a continuous roll.

00:08:51: The joints in the pyro scroll were made with starch based adhesive, typically paste from flour and water.

00:08:57: If that adhesive failed if the joint dried out and cracked it moisture caused it to delaminate.

00:09:02: The scroll broke!

00:09:03: The text was interrupted.

00:09:04: fragments became separated.

00:09:06: When the codex form developed In the first few centuries CE It required more complex adhesive techniques.

00:09:12: Pages needed to be bound at their edges Boards needed to be attached, leather needed to adhereed.

00:09:18: The craft of bookbinding became over centuries one the most technically sophisticated adhesive arts in the world.

00:09:25: The great libraries of ancient and medieval worlds – Alexandria, Constantinople, monasteries of Ireland & England where classical manuscripts were copied and preserved.

00:09:34: their entire function as repositories of human knowledge depended on physical integrity of objects they contained at multiple critical points on the quality of the adhesives holding them together.

00:09:48: There is a direct line from Anjander Tau's birch tower to The Survival of Ars Total.

00:09:53: I don't mean that poetically, i mean that the physical optics through which greek philosophy reached their renaissance –the manuscripts copied and recopied bound and rebound across a thousand years of transmission– are objects in which adhesive failure meant knowledge

00:10:06: loss.".

00:10:07: The monks who copied texts understood this-.

00:10:09: the care they took with their bindings was not just craftsmanship It was preservation.

00:10:14: Glue kept the words of ancient worlds alive long enough for modern world to inherit them.

00:10:19: By the nineteenth century glue is an industrial product and industry that produced it had a problem.

00:10:25: Animal glue, domino adhesive used in furniture book binding textiles footwear and dozens other industries Was made from collagen extracted from animal hides hooves and bones.

00:10:35: The raw materials came from slaughterhouses and tanneries.

00:10:38: The production process involved boiling those materials and large vats for extended period.

00:10:43: And the smell was by contemporary accounts extraordinary, not extraordinary in a good way.

00:10:48: Extraordinary in the sense that it could be detected from a significant distance... That it permeated the clothing and hair of anyone who worked at a glue factory….

00:10:57: ...that entire neighbourhoods downwind over glue works had persistent and mistakable quality to bear.

00:11:04: Glue workers like Tana's, like bone meal processors like the people who worked in their industry that turned animal waste into useful products, occupied a peculiar social position.

00:11:14: They were completely indistensible – The furniture factories, the bootmakers, paper makers and piano manufacturers… none of them could function without these workers' product made.

00:11:24: And yet they were socially marginalised.

00:11:27: Their factories pushed to the edges of towns.

00:11:29: Their occupation regarded with mixture of necessity and distaste.

00:11:33: This is a pattern that appears throughout industrial history.

00:11:35: The people who do the necessary but unpleasant work of turning raw materials into useful products are simultaneously essential and

00:11:42: overlooked.".

00:11:43: The glue makers enabled the Victorian era's extraordinary output of manufactured goods.

00:11:48: The smell at their work was the smell of prosperity, just not in a way that prosperity wanted to acknowledge... with Haiman McKay's shoe-lasting machine transforming production volumes but still requiring adhesives at multiple stages.

00:12:10: The textile industry used size, a starch based adhesive to strengthen threads for weaving.

00:12:15: the wallpaper industry.

00:12:16: ,the packaging industry.

00:12:17: .The growing manufacture of musical instruments where animal glue remains till this day the preferred adhesive for violin and guitar construction.

00:12:25: because it is reversible A joint mate with Animal Glue can be open with moisture & heat allowing instruments repaired.

00:12:32: All of this ran on glue and all the glue run on animal collagen, and all of it smelled.

00:12:38: The twentieth century changed everything as it tends to.

00:12:42: The first synthetic adhesives began appearing in the early nineteen hundreds.

00:12:47: Bacolite –the first fully synthetic plastic- was developed by Leo Baklandt in nineteen oh seven and had adhesive properties alongside its molding uses.

00:12:55: Urea formaldehyde resins appeared in the nineteen twenties and found immediate application of plywood manufacturing, allowing thin sheets of wood to be laminated together into panels with great strength and stability.

00:13:07: PVA, polyvinyl acetate was developed in Germany by the mid-twentieth century – the white glue found at every school or craft room in the world!

00:13:18: The one in a bottle that children have been eating for generations to no apparent harm?

00:13:24: But the adhesive that genuinely changed what was possible, The one that introduced a completely new relationship between materials Was epoxy resin.

00:13:33: Epoxy developed in the late nineteen thirties and commercialized after World War II was two-part adhesive A resin and a hard nut.

00:13:40: when mixed triggered chemical reaction Producing a bond of extraordinary strength That is also resistant to chemicals moisture And temperature extremes.

00:13:50: Epoxy didn't just stick things together, it created a new material that joined harder and after stronger than the materials.

00:13:56: It was bonding!

00:13:57: And then in nineteen fifty-eight an American engineer named Terry Hoover who had actually first synthesized their compound by accident in nineteen forty two while trying to develop clear plastic gun sights for wartime use brought cyanoacrylate to market under the name Eastman nine ten.

00:14:13: The rest of the world knows it as superglue.

00:14:16: Cyano acrylate is chemically extraordinary —it's a monomer a single molecule that polymerizes almost instantly in the presence of very slight alkalinity of moisture.

00:14:26: When you apply superglue to your surface, then moisture on the surface triggers polymerization and within seconds you have a polymer chain that bonds with both surfaces simultaneously.

00:14:36: The bond forms at molecular level not just sitting on top but interacting chemically.

00:14:42: This is why super glue bonds skin so effectively and stubbornly.

00:14:46: Skin is slightly moist and slightly alkaline.

00:14:48: It has essentially the ideal surface for triggering cyanoacrylate polymerization, which a fact that most people learn at worst possible moment!

00:14:57: In forensic science, cyano-acrylate is used to develop latent fingerprints.

00:15:02: The fumed superglue reacts with residues left by fingertips making them visible.

00:15:07: In emergency surgery surgical versions of super glue adhesives are used to close wounds without stitches particularly in situations where speed matters more than aesthetics.

00:15:17: In the Vietnam War, medics used a cyanoacrylate formulation to seal wounds into fields.

00:15:23: Superglue in medical grade form has genuinely saved lives on battlefields.

00:15:27: This is part that I think surprises people most and it's worth understanding clearly.

00:15:31: A bolt – metal fastener screwed through two material holds those materials together by clamping force.

00:15:37: The bolt passes through a hole and not tightens against the surface, And two materials are held by compression between them.

00:15:44: This seems extremely robust and it is under many conditions.

00:15:48: But!

00:15:48: A Bolt has fundamental structural weakness.

00:15:51: It concentrates force.

00:15:53: All distress in a bolted joint Passes thru the bolt itself Through material immediately around Under vibration, under cycling loads the kind of loads that occur in aircraft.

00:16:03: In vehicles and structures that flex or move those concentrated stress points are where failure begins.

00:16:08: The material around the hull fatigues –the bulk loosens-.

00:16:11: cracks initiate.

00:16:12: at this stress concentration point An adhesive bond distributes force completely differently.

00:16:17: Instead of concentrating stress on a single point it spreads across its entire bonded surface.

00:16:22: This stress per unit area is dramatically lower.

00:16:25: Under the same overall load, an adhesively bonded joint experiences much lower peak stress at any single point than a bolted joint carrying the same load.

00:16:34: This is why modern aircraft use adhesive bonding extensively alongside and in some cases instead of mechanical fasteners The Airbus A-III-AT when it entered service in two thousand seven used adhesive bonding at multiple critical structural points.

00:16:48: .The Boeing Seven Eight Seven Dreamliner uses extensive adhesive bonding military aircraft, Formula One cars high-performance bicycles spacecraft or use adhesive as primary structural elements because the weight saving from replacing metal fasteners within adhesive films combined with a performance advantage of distributed stress is significant.

00:17:12: The entire outer skin on smartphone glass front and glass or metal back.

00:17:16: waterproof seals around every component assembled using pressure sensitive adhesives.

00:17:21: UV cured optical adhesive.

00:17:23: The screen of your phone is glued to the frame with optical clarity.

00:17:26: adhesive that transmits light without distortion.

00:17:29: The battery is adhered through the chassis, fingerprint sensor, cameras and speakers all held in precise position by adhesives chosen for their specific combination of bond strength, flexibility thermal conductivity electrical properties.

00:17:43: Your phone is a composite object held together by suit different adhesive each choosen for specific function.

00:17:50: It is, in its fundamental engineering logic not that different from Aneanderthals hachtet tool.

00:17:55: Different materials joined together to achieve something neither material could achieve alone.

00:18:00: Now let me take you somewhere even more interesting Because everything humans have ever made with glue From budge tar To aerospace epoxy Is by the standards of what nature has developed still quite limited.

00:18:13: Consider the barnacle!

00:18:14: A barnicle is a small crustacean That in it's larval stage settles on hard surface and permanently glues itself down.

00:18:21: It does this in saltwater on surfaces that are constantly immersed, constantly exposed to turbulent mechanical forces – constantly subjected the attempts of various organisms and eventually entire shipping industries to remove them.

00:18:34: A barnacle once settled doesn't come off.

00:18:36: The adhesive it secretes, Barnacle Cement forms a bond that shipping companies spend billions of dollars annually trying to scrape from the hulls their vessels And researchers have been trying understand and replicate for decades.

00:18:49: Barnacle cement is a protein-based adhesive that cures underwater bonds to virtually any surface regardless of chemistry and maintains its bond under conditions that would destroy any synthetic adhesive currently available.

00:19:02: The mechanism by which it does this, still not fully understood.

00:19:05: the proteins involved have been identified in their sequences mapped but the precise chemistry at how they interact with surfaces underwater to form such durable bonds remains an active area of research.

00:19:18: Muscles have a different but equally remarkable solution.

00:19:20: They anchor to rocks in the intertidal zone, surfaces that are wet covered and salt frequently subjected to wave forces and periodically exposed to drying.

00:19:29: they do this with a bundle of protein threads called the bisis each thread anchored by a protein adhesive plaque that bonds through rock surface.

00:19:37: The adhesives proteins called muscle adhesive protease or MAPs contain an unusual amino acid modification That is responsible for their underwater bonding ability.

00:19:47: This modification called DOPA has inspired research into surgical adhesive and underwater repair compounds that could work in wet environments where conventional adhesives fail.

00:19:58: And then there is the velvet worm, a velvet worm an ancient lineage of organisms look like caterpillars with stubby legs have been essentially unchanged for five hundred million years.

00:20:08: hunts by firing rapid hardening sticky slime from modified limbs on either side its head The slime jets out as a liquid, wraps around the prey and hardens almost instantly into a fibrous mesh that immobilizes it.

00:20:22: This mechanism is remarkable – the slime is protein solution which transitions from liquid to solid through physical process triggered by mechanical stress of being ejected at high velocity not chemical reaction but physical one!

00:20:35: Honeybees have found use for adhesive studies depending on your perspective either deeply practical or genuinely disturbing.

00:20:43: These collect plant resins and process them into a material called propolis.

00:20:47: A sticky antimicrobial substance used to seal gaps in the hive, coat the interior walls and plug entrances against pathogens and small intruders.

00:20:55: Propolis has potent antibacterial and antifungal properties that keeps the hive environment remarkably clean.

00:21:01: But its most macabre application is this If a small animal, a mouse or large insect wanders onto their hide and dies And the body's too large for worker bees.

00:21:10: They will completely encase the corpse in propolis.

00:21:13: Coat it entirely, seal all from rest of the hide, mummify essentially to prevent decomposition effecting the colony's health.

00:21:21: A bee uses glue as a mortuary tool.

00:21:23: Nature has been exploring their adhesive design space for hundreds and millions years And results make our best synthetic adhesives look like early experiments.

00:21:31: Let me end where we should end with this thing itself.

00:21:34: Glued never conquered an empire.

00:21:36: It never sparked a revolution, it never got its own chapter in history textbook or its own exhibit at the museum.

00:21:43: It held things together quietly and invisibly for two hundred thousand years but has never once demanded credit.

00:21:49: But think about what would not exist without it.

00:21:52: The composite tools that gave early humans a decisive advantage of hunting?

00:21:56: Gone!

00:21:57: The Egyptian furniture survived three millennia?

00:21:59: Gone !

00:22:00: The manuscripts carried classical knowledge through dark ages ?

00:22:03: Gone.

00:22:04: The violence of stradivarius assembled with animal glue chosen for its reversibility, gone.

00:22:10: the aircraft you're flowing in...the fire you carry.. the book on your shelf… the shoes on your feet all held together by quiet technology By a material that joins different things into something neither could be alone.

00:22:22: There is almost something philosophical about this.

00:22:24: The great transformations in human history – the ones genuinely changed what was possible were often not dramatic visible inventions.

00:22:33: They were the enabling technologies.

00:22:36: The things that made other things possible, the wheel gets the credit but the grease that let it turn smoothly is just as important.

00:22:43: The printing press get's the credit But glue that bound books produced preserved what it printed!

00:22:48: The computer gots the credit... ...but the adhesives that hold its components in precise alignment make function.

00:22:55: Glue is the enabling technology underneath every other enabling technology.

00:22:59: The material that says these two things which cannot be one thing can work together as if they were.

00:23:05: And the undertow, two hundred thousand years ago figured this out with birch bark and a fire... ...and nothing has quite been the same since.

00:23:13: So next time you pick up a glue stick or peel the backing of yourself adhesive surface.. ..or notice the line where two materials meet and hold.

00:23:20: just take a second.

00:23:22: You're using all this synthetic material in history on this planet.

00:23:26: A technology older than our species, one that held the words of Aristotle together through a thousand years of copying and binding.

00:23:33: One that joins the glass to frame your phone The sole-to-your shoe The veneer to surface you work at.

00:23:40: It never asks for recognition it just holds.

00:23:44: History isn't only in museums.

00:23:45: Sometimes its invisible line Where one thing meets another and stays.

00:23:50: If this made us think about something we've not thought before That's always the point.

00:23:55: The Hidden Life of Things is on Spotify, Apple Podcasts and wherever you listen.

00:23:59: A follow or a like genuinely helps And if someone in your life Is the kind person who looks at ordinary things and wonders how they work This is their podcast!

00:24:08: Here's your clue for next time.

00:24:11: It has fed more humans than any other food in history.

00:24:14: Half-the world eats it every single day.

00:24:16: Yet its almost invisible In western culture.

00:24:19: Treated as side dish background carbohydrate Something unremarkable In the places where it actually matters, It is anything but.

00:24:26: It has been used as currency As a tax ,as symbol of power so potent that who controlled it controlled entire populations.

00:24:34: The way its cooked varies so dramatically between cultures.

00:24:37: That same grain becomes almost unrecognizable across different kitchens.

00:24:42: And genetic modification Of one variety carried out in later half of the twentieth century by man most people have never heard of Is estimated to have prevented a billion deaths.

00:24:53: What is it?

00:24:54: Stay curious, I'm Alexandra and i'll talk to you next week.