today I'm going to show you how to melt wood and since we know how to melt wood that means that we can actually weld two pieces of wood together 6 years ago I made a video about trying to melt wood and concluded that you can't melt wood I argued that since the polymers of cellulose and lignan are so large their melting point is higher than the thermal decomposition temperature so you have to provide them with so much heat that they break down and release smaller volatiles into the air before they can melt now I wasn't
too far often saying this because this is what happens most of the time when you heat wood that's what burning is have you ever noticed that the flame of a fire isn't on the wood but it's above it that's because the fire isn't burning the solid wood it's burning the gases that are released from the wood when the cellulose hemicellulose and ligant in the wood break down thermally but here's the key when you're dealing with large molecules there isn't really a melting point but that doesn't mean that you can't make it melt that sounds paradoxic
iCal but it's not a melting point is a defined temperature at a given pressure where a material turns from a crystallized State into a state that's has no repeating structure but for longchain molecules there isn't really a single point but the molecules just slowly get less and less organized as the temperature increases until eventually you have a thick liquid the point at which the molecules can move around more like a liquid and have less structure is called the glass transition temperature it's when there's a sudden change in how the material responds to a stress so
is this possible with wood as well well I'm going to try to weld wood together in order to create the heat for the weld I'm going to turn a cylinder of oak wood inside a hole that's a tiny bit smaller than the cylinder in another piece of oak wood this pressure will create a lot of friction and heat okay so I'm just going to drill a hole right in here now I'm just going to turn it at full speed and apply a lot of pressure so it's heating up now after I sto turning it I
have to hold it in place for a bit with that pressure still on it to wait for the melted wood to solidify and Harden again if it doesn't stick you'll know right away it'll just come loose and pop out oh my gosh but now this is solid I can even reverse my drill and try to unscrew it this is solid now if I try to turn it again it just breaks the dowel it's actually welded together inside of this hole I can't get it out this is so strong I can't do anything to pull it
out it's literally like I put a wood glue in here that's holding it [Music] together so when I do a crosssection of it you can see it is actually bonded to the wood in there it's still not falling out even though I've released the pressure from around it so it's acting like it's an adhesive now this really is welded together in fact wood welding has been around almost 20 years wood welding was discovered by mistake actually at a material science lab called The Swiss School they'd been using a machine to glue a piece of wood
together by sticking a piece of plastic in between the two pieces of wood and when they vibrate it and push them together really hard the friction melts the plastic and join the two pieces of wood together but one day by mistake a technician forgot to add the plastic in between the two pieces of wood and to their surprised they found that the two pieces of wood were still bonded together really well they analyzed the wood at a molecular level and found that the wood had actually melted and bonded together they were awarded the schaerer schaer
they were awarded a prize for their Discovery Innovations like this reduce the need for plastic and adhesive waste if you want to join other causes that can help the environment then stick around to the end of this video and I'll tell you about planet wild but what's actually melting in the wood well wood is made up of three main components cellulose hemicellulose and lignan the lignan fills the spaces in the cell walls of the wood it's kind of like the natural glue that holds the fibers of the wood together they found that during wood welding
the lignan is the component that's actually melting specifically the middle Lamela in these images they took you can see that the wood fiber remains intact but they're surrounded with cooled molten ligant when this lignan melts it joins the fibers from one piece of wood with the fibers from the other piece of wood so it's literally joining the two pieces of wood together by melting the ligant in between and bonding them they've done experiments exactly the same as I did here by drilling a cylinder of wood into a hole and they found that they got better
adhesion than actually using an adhesive to glue the wooden dowel in the hole if you want to try this it works best with hardwood that's why I used Oak if you use soft wood the wood collapses under the pressure and so you can't get enough Force to make the welding happen unless you have really extreme forces more than I could put with my hand drill so ultimately it was the heat that melted the ligant in the wood so could we do the same thing by applying heat to a piece of wood and trying to shape
it well when we create the heat from friction we aren't allowing the oxygen to make it to the bulk of the hot wood to react with it so we would need a way to exclude oxygen while applying heat to this so how on Earth would we exclude oxygen oh yeah the vacuum chamber so I'm just going to take this piece of wood wood and I'll bend it in here let's see if we can get it to stay like this okay so I've put two bent sticks in there the first one I'm going to be heating
up and the second one will just be my control to see if it stays bent for some reason I'm going to heat my wood with a laser while it's under vacuum and see if I can permanently deform it due to Melting the ligant around it let's see what this looks like open it up okay that one popped back pretty straight let's see the one we heated it's a little more bent look at that okay here's both of them laid parallel together the control is on top and then the one that I heated was on the
bottom so you can see right after the heating point it starts deviating I mean this is basically what they do when they do curv pieces of wood they get wood wet and then they heat it up really hot but it's not hot enough to melt lignan but it is enough to rearrange the fibers just enough to bend the wood one of the coolest things about being able to melt wood is it removes the need to use adhesives in a lot of cases adhesives are expensive and contain volatile organic compounds and toxic chemicals it's so neat
how we can continue to make advancements that make the world a cleaner place to live in that's why I want to tell you about planet Wild Planet wild is a global nature Protection Organization each month Planet wild collaborates with a new environmental partner worldwide to protect endangered species clean up waterways or restore forests you can become a digital conservationist Planet wild has 100% transparency and you can see the impact that your your contributions have you can download their app and become a member starting at $6 a month with that you get voting power for future
projects and get to see detailed reports from their missions so if you want to help have a direct impact on the environment you can become a member today with the membership you get a video every month showcasing the new project and your name even gets mentioned in the credits of the monthly videos along with your own badge as a momento that you actually help support the program in their latest Mission they're saving baby shark eggs that have been removed from their mothers that had been killed in by catch from catching fish in the industry they
actually grow the sharks from these shark eggs and then release them back into the wild so if you're interested in becoming a member of Planet wild the first 500 people will enjoy the first month of Planet wild membership for free and the best part is you'll see your impact in as little as 30 days from when you become a member you can click the link in the description or scan the QR code and use code action lab 7 for the first month free and thanks for watching the action lab and we'll see you next time
