I accidentally uploaded this at 480p at first, this is a re-upload 2 hours later. Just in case you are wondering where your comment went. Unfortunately, youtube does not allow me to fix a video in place, as I screw up about one in ten uploads this way.
You DO make mistakes!!! That must really upset the German in you to admit that. I know it would me! J/K Matthias ☺Wonderful video as always, very informative. Nice to finally have some data on the various material strengths, this is something the world does need.
@@Koushakur 480p is a test render. I assume this time he caught it fairly quickly so he fixed it. Otherwise he would leave it as to not disturb youtube's algorithm
From what I have learned about steam bending, the wood can compress quite a bit without breaking but not stretch very much at all. A metal band on the outside of the bend will help distribute the forces more evenly and allow it to bend more. They use that technique to bend wooden wheels.
One reason a laminated beam (of the same dimensions) is stronger than a solid one is that these kind of variantions are much lowered since they are randomly spread And since beams often break at their weakest point, this is important. This also means you can use cheaper lumber for glue lam beams.
@@matthiaswandel I wonder (though jeez I'd never suggest that you ought to put in the manual labor to prepare the test stock for this) whether or not you would be able to observe any meaningful difference between sawn wood and riven wood.
This might be the same as what you're saying, but my intuition would be as follows: Laminated wood may be stronger because the lamination creates grain discontinuity. Breaks often occur largely with the grain, rather than the fibers themselves breaking. Of course fibers are often also severed in a break, but there is retty much always fiber separation even when the fibers themselves do sever. The glue line in laminated wood is a point where the fiber separation propagation must terminate, the grain ends there and is connected to a different grain pattern. This won't necessarily stop the break from continuing at this point, but it will at least provide further resistance than a continuous grain line all the way across the piece. Though this is in the perspective of prolongation of a break which has already started forming. I'd presume that similar ideas also lead to resistance of a break from starting until higher stress builds up. Speaking to Scheffler's point, riven wood should have grains traveling almost strictly along the length of the piece and should increase strength for similar reasons, I.E. There should be few continuous grain lines which travel any appreciable distance across the width of the board, so a fracture in that direction has a lot of discontinuities to overcome.
@@herrpauk Velkomm to hudrolik pressss channellll. He did a test with 2×4's and 4x4's recently (Finland being metric / not the US, they are not 2x4'd per se...)
Probably way more than I’ll ever need to know about the relative strength and bendability of (non-laminated) wood… but it sure was interesting! And if there ever comes a time when either of those things is an issue in one of my projects, I’m sure I’ll refer back to this excellent video. Thanks, Matthias! You certainly have a knack for posting informative, useful content that can’t be found anywhere else on RUclips!
The Amish in my local community would soak the wood for their rocking chairs in oil for several days before bending them to shape. There are obviously different methods, but I appreciate you for sharing all your hard work with the RUclips community.
You might be interested in the 4-point method of testing materials in bending. Instead of applying load in the center, load is applied at two locations, nearer to the supports. This creates a more even bending moment, and is less sensitive to localised effects Edit: also, the beam vertical shear load is negated, so you get almost pure bending stress along the mid-span
The real trick to steam/wet bending wood is keeping a compression band on the outside of the bend. The oven baking to avoid springback was a very interesting result.
I really love your videos and after watching your other video explaining the problems with your viewing algorithms, I'm re-watching this video just to help you get things back on track. I often wonder how you decided on wood working? You have to be one of the smartest people I know and could make videos on just about any subject and they'd all be awesome.
My best results for bending were always to take the piece of wood I wanted to bend, slice it into several thin layers, soak those, paint the layers with glue and clamp them all back together in a curved jig. Extra steps, but it was pretty reliable.
I wanted to know about bending the actual wood. Bent laminations aren't so much bending the wood itself, because thinner layers need a lot less bending to get the same radius.
You almost described a boat building process called cold-molded wood construction except, its epoxy soaked wood laid in alternating layers instead of regular glue. Boat builders also tend to cover both sides in fiberglass but, that's more for water protection than the added strength the fiberglass provides.
funny ...if you keep on playing with the test machine, you'll discover ...what in the books of "Resistance of Materials" is written 😂 It's great. It reminds me my first year at University in the materials lab. You can also build different trusses, porticoes and beams with balsa wood and test them. In my Uni we had model competitions it's really funny and very instructive to compare your "theoretical numbers" with what in reality happens and study the collapse.
Wow, talk about a video being hot out of the oven. Tracking says that my parcel reached your door only today. You are now in possession of wood samples that are worth about $30 per board foot, accounting for shipping! I feel for John.
You should try the same tests with riven wood which would give a truer measure of the wood strength it is also the best to use when bending wood as there is no grain runout to start splintering.
Great video Matthias - always enjoy your testing videos. The graphs etc. that you've started using are really interesting and a great addition. By the way, I noticed an entertaining typo at 5:58: "soaked in wood" :) Thanks for the continued quality content.
I believe a four point test would be much better for wood applications. The problem with a three point test is you only check one single cross section of the sample where the point load is. With a four point bending test you achieve a constant moment across the two loading points, this also gives a constant maximum stress on the top and bottom of the sample in tension and compression. This gives more accurate and repeatable results. Then you have to consider I believe it’s called a Weibul modulus which is the statistical certainty that a fracture will happen within some loading tolerance, this is important when manufacturing isn’t precious.
Thanks for posting. Fun science at home. Engels Coach Shop channel has a video on steam bending wood for wagon wheels, hoops etc. He really knows what he’s doing.
That seems to be quite nice setup you have there. I would love to tinker with something like that too. :) You could now calculate the ultimate bending strength of the wood pieces you have there and compare them to typical strengths of the wood species you used. The bake test at the end was super interesting too. I may have to make some moldings for my car's floor and I have been thinking about using wood. Flexible moldings available from the hardware store are reeeeally expensive. Also about the "baked" wood.. It is used to create more weather and mold resistant boards to be used in terraces and facades without any paint or other surface coating. In the process, the lignine goes away. Like you discovered, the wood becomes more brittle too and usually the boards require pre-drilled holes before screwing them to base. Thermally processed wood is good for outdoors and doesn't require impregnating the wood with sulfides in high pressure. The strength should also go up a little in the thermal treatment.
I wonder if you've heard of the work of American Civil War General Herman Haupt? Here's a short quote from an article about him. "In 1840, at work on the York & Wrightsville, he grew suspicious of the design of the road’s latticework bridges and found to his astonishment that there was not a single engineer in the United States who had ever tried to calculate the strain of any even slightly complex bridge truss. He put a decade into the subject and produced his General Theory of Bridge Construction , which publishers at first shunned because they could find no engineer qualified to review it. But when the book finally appeared in 1851, it was an instant success and established its author as an authority in the field. "
Amazing how much stress such a small piece of wood can actually withstand before breaking! I would be interested in how plywood holds up in comparison to normal wood. I personally would expect it to fail sooner, because only half of the grain is running in the direction of stress, but you can find conflicting information on the internet.
The shear stress limit varies greatly by species of wood, and plywood helps in that regard. My guess is pine will be about the same as plywood, maybe a little higher, whereas oak would be way higher than plywood.
Very grateful for the data. I world love to see some end gain balsa composite materials tested some day, but that's probably too niche for your audience.
Nice. Maybe test pieces with a nail/screw in it. Or with a hole from a removed fastener. Leave some pieces outside in the rain etc. Or exposed in the sunlight
Hi Matthias, I really enjoy your testing videos. Would love to see them applied to more consumer devices, although I know that can get expensive, which is the opposite of how your channel works.
You need to check out Project farm if you want to see that kind of stuff. He is one of the best I've ever seen, you will love his methodology. Every manufacturer should be vying for a coveted "Project Farm Approved" sticker on their products.
That is a great test apparatus. I'd be interested in comparing breaking forces for the same piece of wood between two grain orientations: first when the grain plane is normal to the applied force and second when the grain plane is parallel to the applied force.
The other thing I'd be interested in would be testing the same joint with various thickness of wood for the wood member on which the force is applied to. Depending on the joint member, the effective thickness of the wood may be decreased because of the joint method (e.g. in the cases of a domino, dowel, tongue and groove, screw or nail joint) as the wood member is in effect supported by the joint fastener. So the part (thickness) of the wood member above the fastener provides most of the resistance to the applied force, however, the part of the wood member below the fastener also contributes somehow. The question is how much is that contribution and, therefore, at which thickness distance in the wood member should the joint fastener be placed for maximum resistance to fracture.
Hey Matthais I had an idea for another experiment. Measuring wood expansion from outdoor temp to indoor (really effects moulding and floating wood floors) as well as humidity changes.
I imagine grain runout is going to be a huge factor in the breaking point for each sample piece. Perhaps categorising samples based on runout [none - some - significant per X INCHES or CM] to determine if there is a correlation would be interesting. This would be further compounded by runout along two faces rather than just one. I would guess that timber with the least runout and the highest moisture content would be the least likely to break, as that is what we look for when steam bending pieces. Orientation of the runout in your testing jig would also affect results. Super interesting stuff as always.
I recommend that you read up on 4 point bending to see if the results from that testing might be more enlightening. It creates a uniform bending moment between the two inner load points.
Most things people make from wood are stationary, and therefore don't need to have strength while bending very much at all. There is a very unique outlier though, a wooden bow, as in archery. There is a series of books known as the Bowyer's Bible which Dives deep into the subject matter. I would highly recommend it to anyone who is trying to get the maximum amount of strength of a moving, bending piece of wood. It also has a lot of information of ancient peoples and their weapons, along with modern testing methods, then combining all the information to get the most out of a bent stick.
Almost all fracture testing methods use a test sample that has some sort inherrent stress intensifying shape (e.g. Charpy V-notch) this is so that the failure point it alwas at the same point with respect to the aparatus negating the effect stress risers dues to imperfections/discontinuities in the sample. You might see much more consistent results if you tried this.
You come up with some interesting and well backed videos. I was just wondering how far one of those amazing maze mice might bend beyond their obvious capabilities.
Another interesting scientific test. I really enjoy these things. Learning what, when and how helps give some reliable forecasts of how timber can hold up to demands over time. Keep them coming.
Any chance you could provide an update on your white/red oak cutting board ?? I just finished one of my own and would love to know how yours has held up over the years!
Hi Matthias, did you note the direction of the grain of the wood pieces? It would be interesting to see how the stiffness differs between flat sawn (horizontal grain direction) and quarter sawn (vertical grain direction). I still haven't found any good comparison (same wood dimension but different grain direction) on that subject
Matthias, What would happen if you glued two pieces of wood so that they were the same thickness as the ones in this experiment? Would it be stronger or weaker? Hope it gets tested! Tnx for the video.
you should use your new tester to see whether leaving a joint under clamps for an extended period of time (say 24h) will give u a stronger bond in the long run, instead of just the working time or as little as minutes or similar. :D
All fairly 'normal' stuff for a wooden boat builder. Ash will bend easier than oak and white oak bends much better than red oak. Also, using a back strap of thin metal or leather will prevent a lot of breakage.
@@matthiaswandel Thanks. One me thought about the curved stick stress test, I wonder if perhaps it might perform better flipped,it's less intuitive but it might just work.
Take a band saw blade and clamp it to the outside of your test piece. this should help and keep it from splitting on the outside of the bend. Not in your machine but when bending by hand.
Your data presentation would benefit from some basic statistics to describe the relationships. Variance, standard deviation and correlation would be helpful. Student's T, Chi square and F would be useful for your treatment experiments.
I would love to see break tests of soaked wood that was then wrapped in something to prevent evaporation and then heated. That way the surface wouldn't be drying off like in these tests.
Very imteresting video. One thought: your first experiment with soaked wood versus heated seem to indicate that moisture affects elasticity. But you did not account for moisture content, which could perhaps have been done by baking equal volumes of wood for a long time, and weighing the wood before and after. Then with similar wood and volume, weigh and soak until no more water is absorbed, then wipe and weigh again. It seems that dry wood becomes brittle, which seems reasonable. Also, it look to me, intuitively, that would should perhaps not just be distinguished as hard vs soft, but also dense vs light. Disclaimer: I'm just a curious layman, not a materials scientist.
@@matthiaswandel thank you for the confidence. But I would not be able to do your video justice, neither in form nor content, I noticed others mentioning thoughts along the same line, so I can just hope someone else, more capable than me, has a go at it.
I accidentally uploaded this at 480p at first, this is a re-upload 2 hours later. Just in case you are wondering where your comment went. Unfortunately, youtube does not allow me to fix a video in place, as I screw up about one in ten uploads this way.
You DO make mistakes!!! That must really upset the German in you to admit that. I know it would me! J/K Matthias ☺Wonderful video as always, very informative. Nice to finally have some data on the various material strengths, this is something the world does need.
This makes me wonder why you have a 480p version to mistakenly upload to begin with. I'm sure you have a reason but I'm currently not seeing it.
I would never notice since I view in 480p anyway. :-)
I wonder how the wood behaves during and after freezing in a dry and wet form.
@@Koushakur 480p is a test render. I assume this time he caught it fairly quickly so he fixed it. Otherwise he would leave it as to not disturb youtube's algorithm
From what I have learned about steam bending, the wood can compress quite a bit without breaking but not stretch very much at all. A metal band on the outside of the bend will help distribute the forces more evenly and allow it to bend more. They use that technique to bend wooden wheels.
One reason a laminated beam (of the same dimensions) is stronger than a solid one is that these kind of variantions are much lowered since they are randomly spread
And since beams often break at their weakest point, this is important.
This also means you can use cheaper lumber for glue lam beams.
Now we just need Hydraulic Press Channel to measure and wrecks some 4x4, laminated beams etc.. take it up a notch.. ;)
yes. though for this test, since I only broke pieces without defects, that wouldn't make much difference.
@@matthiaswandel I wonder (though jeez I'd never suggest that you ought to put in the manual labor to prepare the test stock for this) whether or not you would be able to observe any meaningful difference between sawn wood and riven wood.
This might be the same as what you're saying, but my intuition would be as follows:
Laminated wood may be stronger because the lamination creates grain discontinuity. Breaks often occur largely with the grain, rather than the fibers themselves breaking. Of course fibers are often also severed in a break, but there is retty much always fiber separation even when the fibers themselves do sever. The glue line in laminated wood is a point where the fiber separation propagation must terminate, the grain ends there and is connected to a different grain pattern. This won't necessarily stop the break from continuing at this point, but it will at least provide further resistance than a continuous grain line all the way across the piece.
Though this is in the perspective of prolongation of a break which has already started forming. I'd presume that similar ideas also lead to resistance of a break from starting until higher stress builds up.
Speaking to Scheffler's point, riven wood should have grains traveling almost strictly along the length of the piece and should increase strength for similar reasons, I.E. There should be few continuous grain lines which travel any appreciable distance across the width of the board, so a fracture in that direction has a lot of discontinuities to overcome.
@@herrpauk Velkomm to hudrolik pressss channellll.
He did a test with 2×4's and 4x4's recently (Finland being metric / not the US, they are not 2x4'd per se...)
It's such a pleasure to watch your intelligents in action Matthias, thank you for the videos😁
Probably way more than I’ll ever need to know about the relative strength and bendability of (non-laminated) wood… but it sure was interesting! And if there ever comes a time when either of those things is an issue in one of my projects, I’m sure I’ll refer back to this excellent video. Thanks, Matthias! You certainly have a knack for posting informative, useful content that can’t be found anywhere else on RUclips!
I'm excited to see another wood related experiment from you. Your older ones on screw and glue joints are what originally brought me to your channel.
The Amish in my local community would soak the wood for their rocking chairs in oil for several days before bending them to shape. There are obviously different methods, but I appreciate you for sharing all your hard work with the RUclips community.
You might be interested in the 4-point method of testing materials in bending. Instead of applying load in the center, load is applied at two locations, nearer to the supports. This creates a more even bending moment, and is less sensitive to localised effects
Edit: also, the beam vertical shear load is negated, so you get almost pure bending stress along the mid-span
likewise, a notched specimen test like edge notch or CT would probably result in more consistent fracture data.
The real trick to steam/wet bending wood is keeping a compression band on the outside of the bend. The oven baking to avoid springback was a very interesting result.
I am always amazed at the innovative ideas you have. Even stuff I have not interest in is interesting when you present it. eric on the other coast.
Well said, I also have no interest, but the process and summarizing of data is absolutely amazing! I'm sure many other engineers are very envious!
I really love your videos and after watching your other video explaining the problems with your viewing algorithms, I'm re-watching this video just to help you get things back on track. I often wonder how you decided on wood working? You have to be one of the smartest people I know and could make videos on just about any subject and they'd all be awesome.
I have to say this a very extravagant way to make firewood. ;)
kindling, to be precise
My best results for bending were always to take the piece of wood I wanted to bend, slice it into several thin layers, soak those, paint the layers with glue and clamp them all back together in a curved jig. Extra steps, but it was pretty reliable.
I wanted to know about bending the actual wood. Bent laminations aren't so much bending the wood itself, because thinner layers need a lot less bending to get the same radius.
You almost described a boat building process called cold-molded wood construction except, its epoxy soaked wood laid in alternating layers instead of regular glue. Boat builders also tend to cover both sides in fiberglass but, that's more for water protection than the added strength the fiberglass provides.
@@Jack-yl7cc Yes, that's where I first got the idea. I read about cold molding in an old issue of Fine Woodworking and went from there.
Can’t wait for more of this. So much fun to be along with you on this.
What if you bend much slower, maybe a day or 2. does the force decrease over time? Can you bend further before breaking?
What I learned: The likelihood of breakage of a given sample bears a strong positive correlation with an increase of applied force.
THE MOAR YOU KNOW
funny ...if you keep on playing with the test machine, you'll discover ...what in the books of "Resistance of Materials" is written 😂
It's great. It reminds me my first year at University in the materials lab.
You can also build different trusses, porticoes and beams with balsa wood and test them. In my Uni we had model competitions it's really funny and very instructive to compare your "theoretical numbers" with what in reality happens and study the collapse.
Great! Now I can watch the video again at a higher resoution
Wow, talk about a video being hot out of the oven. Tracking says that my parcel reached your door only today. You are now in possession of wood samples that are worth about $30 per board foot, accounting for shipping! I feel for John.
Only youtuber that can break 100 pieces of wood and make it interesting to watch.
This is fascinating. Looking forward to the next round of tests.
You should try the same tests with riven wood which would give a truer measure of the wood strength it is also the best to use when bending wood as there is no grain runout to start splintering.
That's more consistent than I would have guessed, very interesting.
I couldn't tell the difference since I was only listening the first time. I'll rewatch this just for the algorithm.
Missed opportunity: “Welcome to the Servo Press Channel. I’m Lauri, and I’m Anni. Today we are going to crush hydraulic press with servo press!”
FarmCraft 101 and Matthias Wandel, the crossover episode we didn’t even know we needed.
If you use a thin steel strip on the outside fibre while bending you can prevent splintering on hot steamed pieces.
A very complicated means of turning larger chunks of wood into fairly consistently shaped bits of kindling.
Looking forward to seeing all the different species!
Great video Matthias - always enjoy your testing videos. The graphs etc. that you've started using are really interesting and a great addition. By the way, I noticed an entertaining typo at 5:58: "soaked in wood" :) Thanks for the continued quality content.
this water was soaked in wood
I believe a four point test would be much better for wood applications. The problem with a three point test is you only check one single cross section of the sample where the point load is. With a four point bending test you achieve a constant moment across the two loading points, this also gives a constant maximum stress on the top and bottom of the sample in tension and compression. This gives more accurate and repeatable results. Then you have to consider I believe it’s called a Weibul modulus which is the statistical certainty that a fracture will happen within some loading tolerance, this is important when manufacturing isn’t precious.
I love your analysis!! Great video! 👏
Thanks for posting. Fun science at home. Engels Coach Shop channel has a video on steam bending wood for wagon wheels, hoops etc. He really knows what he’s doing.
excel 2001 or possibly excel '97
Matthias -- You ROOL!
2000. Unlike newer versions, it just keeps getting faster as computers get faster!
That seems to be quite nice setup you have there. I would love to tinker with something like that too. :) You could now calculate the ultimate bending strength of the wood pieces you have there and compare them to typical strengths of the wood species you used.
The bake test at the end was super interesting too. I may have to make some moldings for my car's floor and I have been thinking about using wood. Flexible moldings available from the hardware store are reeeeally expensive.
Also about the "baked" wood.. It is used to create more weather and mold resistant boards to be used in terraces and facades without any paint or other surface coating. In the process, the lignine goes away. Like you discovered, the wood becomes more brittle too and usually the boards require pre-drilled holes before screwing them to base. Thermally processed wood is good for outdoors and doesn't require impregnating the wood with sulfides in high pressure. The strength should also go up a little in the thermal treatment.
5:54: 1080p quality "Soaked in wood", still an amusing typo :)
There was no time to fix that.
I like the unintentional meming lol
I wonder if you've heard of the work of American Civil War General Herman Haupt? Here's a short quote from an article about him. "In 1840, at work on the York & Wrightsville, he grew suspicious of the design of the road’s latticework bridges and found to his astonishment that there was not a single engineer in the United States who had ever tried to calculate the strain of any even slightly complex bridge truss. He put a decade into the subject and produced his General Theory of Bridge Construction , which publishers at first shunned because they could find no engineer qualified to review it. But when the book finally appeared in 1851, it was an instant success and established its author as an authority in the field. "
Lignin, it's all about the lignin. To achieve tight bends, it's helpful to have a compressing strap on the outer circumference
I enjoyed this video beyond rational explanation.
I mean hes literally a wood scientist at this point, he will cure cancer with wood
Amazing how much stress such a small piece of wood can actually withstand before breaking!
I would be interested in how plywood holds up in comparison to normal wood.
I personally would expect it to fail sooner, because only half of the grain is running in the direction of stress, but you can find conflicting information on the internet.
I think it would depend on the orientation of the plys. I would predict that having the layers stacked in the Z axis would be strongest.
The shear stress limit varies greatly by species of wood, and plywood helps in that regard. My guess is pine will be about the same as plywood, maybe a little higher, whereas oak would be way higher than plywood.
Amazed how Excell 1998 gets better and better.
Matt, you are a Golden God.
Another Matthias classic. Thanks man!
you come up with some very interesting projects
Very grateful for the data. I world love to see some end gain balsa composite materials tested some day, but that's probably too niche for your audience.
absolutely amazing test and results
Nice.
Maybe test pieces with a nail/screw in it. Or with a hole from a removed fastener.
Leave some pieces outside in the rain etc. Or exposed in the sunlight
This is great info for future wood bending!
“Boring” content on the main channel! I love it!
Compression bends stop the out cracking , place a metal strap alongside with stops on each end. Ps love your work.
You’re the wood shop version of America’s Test Kitchen.
Hi Matthias, I really enjoy your testing videos. Would love to see them applied to more consumer devices, although I know that can get expensive, which is the opposite of how your channel works.
You need to check out Project farm if you want to see that kind of stuff. He is one of the best I've ever seen, you will love his methodology. Every manufacturer should be vying for a coveted "Project Farm Approved" sticker on their products.
Reads title, YES, a Wandel quality comparison video. Hopefully he explains the apparatus too.
That is a great test apparatus.
I'd be interested in comparing breaking forces for the same piece of wood between two grain orientations: first when the grain plane is normal to the applied force and second when the grain plane is parallel to the applied force.
Excellent video, thanks for this highly useful data! :-)
Matthias, when you do the second break on the same piece of wood, would grain orientation make any difference?
The other thing I'd be interested in would be testing the same joint with various thickness of wood for the wood member on which the force is applied to.
Depending on the joint member, the effective thickness of the wood may be decreased because of the joint method (e.g. in the cases of a domino, dowel, tongue and groove, screw or nail joint) as the wood member is in effect supported by the joint fastener. So the part (thickness) of the wood member above the fastener provides most of the resistance to the applied force, however, the part of the wood member below the fastener also contributes somehow. The question is how much is that contribution and, therefore, at which thickness distance in the wood member should the joint fastener be placed for maximum resistance to fracture.
Typing from the oak desk I made has shown me the breaking point for oak will not be reached on my desk until the kids try to move it after I'm dead.
As with all your stuff this was super interesting.
Hey Matthais I had an idea for another experiment. Measuring wood expansion from outdoor temp to indoor (really effects moulding and floating wood floors) as well as humidity changes.
Once an engineer, always an engineer.
When the wood reaches its ultimate force, you know what’s up
I imagine grain runout is going to be a huge factor in the breaking point for each sample piece. Perhaps categorising samples based on runout [none - some - significant per X INCHES or CM] to determine if there is a correlation would be interesting. This would be further compounded by runout along two faces rather than just one. I would guess that timber with the least runout and the highest moisture content would be the least likely to break, as that is what we look for when steam bending pieces. Orientation of the runout in your testing jig would also affect results. Super interesting stuff as always.
You have learned how to turn firewood into firewood.
I recommend that you read up on 4 point bending to see if the results from that testing might be more enlightening. It creates a uniform bending moment between the two inner load points.
Most things people make from wood are stationary, and therefore don't need to have strength while bending very much at all. There is a very unique outlier though, a wooden bow, as in archery.
There is a series of books known as the Bowyer's Bible which Dives deep into the subject matter. I would highly recommend it to anyone who is trying to get the maximum amount of strength of a moving, bending piece of wood. It also has a lot of information of ancient peoples and their weapons, along with modern testing methods, then combining all the information to get the most out of a bent stick.
Almost all fracture testing methods use a test sample that has some sort inherrent stress intensifying shape (e.g. Charpy V-notch) this is so that the failure point it alwas at the same point with respect to the aparatus negating the effect stress risers dues to imperfections/discontinuities in the sample. You might see much more consistent results if you tried this.
That was awesome. You engineer/physicist/scientist in me want to go down the rabbit hole with you
I really enjoy the scientific method. :) very nice.
You come up with some interesting and well backed videos.
I was just wondering how far one of those amazing maze mice might bend beyond their obvious capabilities.
Another interesting scientific test. I really enjoy these things. Learning what, when and how helps give some reliable forecasts of how timber can hold up to demands over time. Keep them coming.
Any chance you could provide an update on your white/red oak cutting board ?? I just finished one of my own and would love to know how yours has held up over the years!
been using it since I made it. But there's nothing to update. We just use it. Every two years or so I smear some extra salad bowl finish on it.
@@matthiaswandel thanks! It’s going to be hard when I make that first cut into the quartersawn surface!
Would the pressure point (load) at which the wood samples break vary by length as well?
I feel I should pay taxes for this sort of empiricism
At 5:53 you've noted that the piece was soaked in wood. Boy, I'll say!
I thought this episode was great! I also think John from Farm Craft is also great! He seems like the nicest guy! Plus we are from the same place.
She was very interesting when considered in terms of Hazard trees.
Hi Matthias, did you note the direction of the grain of the wood pieces? It would be interesting to see how the stiffness differs between flat sawn (horizontal grain direction) and quarter sawn (vertical grain direction). I still haven't found any good comparison (same wood dimension but different grain direction) on that subject
Oh strange, my wood bends left from factory. Great video btw !
Matthias, What would happen if you glued two pieces of wood so that they were the same thickness as the ones in this experiment? Would it be stronger or weaker? Hope it gets tested! Tnx for the video.
you should use your new tester to see whether leaving a joint under clamps for an extended period of time (say 24h) will give u a stronger bond in the long run, instead of just the working time or as little as minutes or similar. :D
I hope your place has a fireplace! All these tests are yielding you lots of firewood!
Perfect time of year for steaming
All fairly 'normal' stuff for a wooden boat builder. Ash will bend easier than oak and white oak bends much better than red oak. Also, using a back strap of thin metal or leather will prevent a lot of breakage.
I was going to mention the backing strap, thanks for saving me the trouble. Wooden instrument builders use that method all the time.
You managed to make an ad for Audible without ever mentioning it!
That was a podcast. No need to sign up for anything to listen to that.
@@matthiaswandel Thanks.
One me thought about the curved stick stress test, I wonder if perhaps it might perform better flipped,it's less intuitive but it might just work.
I'm jealous of your version of Excel.
Canadian guy breaks 100 pieces of wood.
Me: now that's interesting
I would be curious how they would do freezing them. If room temp does better than hot would frozen do better than room temp?
Take a band saw blade and clamp it to the outside of your test piece. this should help and keep it from splitting on the outside of the bend. Not in your machine but when bending by hand.
This is extremely interesting!
It kind of looks like lignin becomes less plastic after its heated and then cooled. I wonder if that effect is cumulative?
Your data presentation would benefit from some basic statistics to describe the relationships. Variance, standard deviation and correlation would be helpful. Student's T, Chi square and F would be useful for your treatment experiments.
What is the worst that can happen to the test pieces... become firewood.
I would love to see break tests of soaked wood that was then wrapped in something to prevent evaporation and then heated. That way the surface wouldn't be drying off like in these tests.
Very imteresting video.
One thought: your first experiment with soaked wood versus heated seem to indicate that moisture affects elasticity. But you did not account for moisture content, which could perhaps have been done by baking equal volumes of wood for a long time, and weighing the wood before and after. Then with similar wood and volume, weigh and soak until no more water is absorbed, then wipe and weigh again. It seems that dry wood becomes brittle, which seems reasonable. Also, it look to me, intuitively, that would should perhaps not just be distinguished as hard vs soft, but also dense vs light. Disclaimer: I'm just a curious layman, not a materials scientist.
I will leave it to you to do that.
@@matthiaswandel thank you for the confidence. But I would not be able to do your video justice, neither in form nor content, I noticed others mentioning thoughts along the same line, so I can just hope someone else, more capable than me, has a go at it.
Perfect kindling.
Will you make laminated beams, the same size and weight, to do a break test?
The machine for stress test congrat
Mathias, would you test dyed and stabilized wood pieces to see how much strength and or brittleness is gained from the stabilizing process?
send some