Glue Myths Video

[John Ziebron]

For those of you who have seen this recent video I found it quite enlightening.

https://www.youtube.com/watch?v=m7HxBa9WVis

[Jebediah Eckert]

Wow, interesting. Looking for the discussion to follow……

[Stan Calow]

Yes, that was very interesting. Thanks. I wonder how different the results would be with glues other than PVA?

[Mark Rainey]

Fascinating!

[Frederick Skelly]

Interesting for sure. I think I'll glue up some end grain butt joints and see how/where they break. Just to see it for myself. Thanks for posting!

[Robert Hayward]

Thank you for posting this. I thoroughly enjoyed watching it and was surprised by the results.

[johnny means]

His conclusion is wrong and unsupported. He says that the end grain joint is stronger than the long grain joint. He also says that the long grain glue-ups never failed at the joint. His data tells us nothing about how much force it would take to break the long grain joint. Further more, his square pieces are not representative of real world situations.

[Frederick Skelly]

His conclusion is wrong and unsupported. He says that the end grain joint is stronger than the long grain joint. He also says that the long grain glue-ups never failed at the joint. His data tells us nothing about how much force it would take to break the long grain joint. Further more, his square pieces are not representative of real world situations.

Please understand that Im not trying to be a wise guy by asking this. I think Im just missing something..... If the end grain glue up does not fail at the joint, doesnt that mean the strength of the joint is determined by the strength of the wood? If so, why would the strength of the long grain joint be different? It did not break at the glue line - the wood broke.

[Jonathan Jung]

I am grateful not to have been taught early on that end grain is inherently weak. Done properly, I would generally agree with the video. The main problem people experience with end grain, in my opinion, is that most don't let the glue soak in then reapply, instead they just apply a "normal" amount then end up with a starved joint because the majority of the glue got pulled into the end grain.

[Doug Garson]

I am grateful not to have been taught early on that end grain is inherently weak. Done properly, I would generally agree with the video. The main problem people experience with end grain, in my opinion, is that most don't let the glue soak in then reapply, instead they just apply a "normal" amount then end up with a starved joint because the majority of the glue got pulled into the end grain.
Except that he did exactly what you said was the main problem that most people do. He didn't let the glue soak in and then reapply, he just applied a normal amount and glued it up.

[Andrew Hughes]

I can only think of one design detail that requires end grain to end grain. It’s the bottom of a table legs.
Never would I just rely glue. A dowel is what I’ve used in the past before I owned the festool domino.
Everyone should do their own testing

[andrew whicker]

Hard to argue with those results! We've been had.

Now when do we get to eat food off of coatings other than butcher block oil?

[johnny means]

Please understand that Im not trying to be a wise guy by asking this. I think Im just missing something..... If the end grain glue up does not fail at the joint, doesnt that mean the strength of the joint is determined by the strength of the wood? If so, why would the strength of the long grain joint be different? It did not break at the glue line - the wood broke.

The end grain joint did fail at the glue line. The long grain glue ups never failed at the glue line, so we have no idea how much force would be needed to break that joint. I suspect his experiment would have yielded different results if he had loaded the assemblies on edge in order to remove the weakness of the wood from the equation. Maybe if he had cleaved them apart.

[Jerry Wright]

In my experience, most furniture glue joints fail over time due to repeated expansion - contraction. The edge/end joints he shows will certainly fail this way. I have made countless picture frames with mitered 45 degree corners. Even before time for expansion contraction, drop it on the floor and the joint will separate at the glue line...hence the reason for splining joints. There are many reasons for end grain scarf joints and mortised face frame corners beyond endgrain joint strength. Most involve resistance to expansion/contraction shear forces.

[Clint Baxter]

(Also posted this on another forum discussing the same video)

What seems to be missing from the equation is that and end-grain glued joint is stronger than short grain wood fibers. By testing all these using these small blocks, his small wood samples all have a small cross section of long grain wood. Would you ever try to use a shelf made with the grain running opposite to the length of the shelf? Not likely because the wood itself does not have it's strength in that orientation.

It is my belief that he is not actually testing an end-to-end grain joint against an end-to-side grain joint, and likewise to a side-to-side grain joint. He is instead testing the joint, and the adjoining wood, which due to the short grain samples, are the points that are actually failing, not the joint, as demonstrated in his presentation.

He showed that the long grain of the wood was much stronger than any of the joints that he tested, but never showed a joint that extends a sample in the long grain direction, joined by a side grain-to-side grain joint. He should take another of his samples and glue them face to face, using only 3/4 of an inch for his overlap to keep the size of the actual glue joint the same, and then test that against his other samples. I would be surprised if he did not come out with a much different summary.

A better way to describe the results of his test would be, "An end grain to end grain joint is stronger than the strength of short grain wood fibers."



Clint

[roger wiegand]

One of the things that I learned working as a scientist is that when the data from your experiment contradict what you see happening in the real world, 99.9% of the time you have a problem with your experiment.

Having repaired perhaps 100 mitered picture frames over the decades where 100% of them had failed at the near end-grain miter joint while having only seen long grain joints fail in situations where the glue was seriously degraded by extreme age or by flood damage, I have to say I'm skeptical. I'm not a material science guy, so I'm not going to critique the testing methodology, but the outcome reeks of an artifact of the specific methodology employed.

I for one am not about to glue two 2x10's together end to end and then stand on the piece as planking on a scaffold.

[Frank Pratt]

One of the things that I learned working as a scientist is that when the data from your experiment contradict what you see happening in the real world, 99.9% of the time you have a problem with your experiment.

Having repaired perhaps 100 mitered picture frames over the decades where 100% of them had failed at the near end-grain miter joint while having only seen long grain joints fail in situations where the glue was seriously degraded by extreme age or by flood damage, I have to say I'm skeptical. I'm not a material science guy, so I'm not going to critique the testing methodology, but the outcome reeks of an artifact of the specific methodology employed.

I for one am not about to glue two 2x10's together end to end and then stand on the piece as planking on a scaffold.

And the way he states the results serve to confirm his conclusion & confuse the issue. The bottom line is that an end grain to end grain glue joint is still far weaker than a solid piece, whereas a long grain to long grain joint is stronger than the surrounding wood.

He has not proven or shown anything that is not common knowledge. He just presented it differently. But the reaction to his findings do show that most people need a bit of education in this area.

[Andrew Hughes]

And the way he states the results serve to confirm his conclusion & confuse the issue. The bottom line is that an end grain to end grain glue joint is still far weaker than a solid piece, whereas a long grain to long grain joint is stronger than the surrounding wood.

He has not proven or shown anything that is not common knowledge. He just presented it differently. But the reaction to his findings do show that most people need a bit of education in this area.

Thats really well said Frank.

[Mark Bolton]

In my experience, most furniture glue joints fail over time due to repeated expansion - contraction. The edge/end joints he shows will certainly fail this way. I have made countless picture frames with mitered 45 degree corners. Even before time for expansion contraction, drop it on the floor and the joint will separate at the glue line...hence the reason for splining joints. There are many reasons for end grain scarf joints and mortised face frame corners beyond endgrain joint strength. Most involve resistance to expansion/contraction shear forces.

And Jerry for the win!! Well said.

[Keegan Shields]

Oh wait, some guy on YouTube has discovered one neat trick for gluing end grain... This is how you drive clicks and views.

I think the unfortunate reality is that life is pretty boring and instances where people disprove conventional wisdom is exceedingly rare. And those big events are usually accompanied by a technology innovation (like a new type of glue for instance).

Does it happen? Yes! Just not nearly as much as YouTube videos or the internet would have you believe.

[Jim Dwight]

I think it is myth that there is any relevant information in that video.

Side grain to side grain failed in the wood, not at the joint. No surprise, we know wood is weaker across the grain. Doesn't really tell us the glue joint of side grain to side grain is weak.

End grain to side grain was strong but it won't stay that way. We all know wood moves across the grain, very little along the grain. So the end grain portion will move and fail the joint as humidity changes. So it is still a weak joint, it will just take a little time to fail.

End grain to end grain failed at the glue line. So the joint was the weakest portion of the piece. If we knew that wood moved uniformly across both pieces with humidity changes then it might stay together but I suspect it will not move uniformly and this joint will fall apart.

The myth the creator of the video is creating is that the reason we don't glue to end grain is weakness of the glue joint initially. That is not the case. We do not glue to end grain because of wood movement with humidity changes. The wood movement will fail the end grain joint.

If you still think end grain joints are a good idea think about why trim manufacturers finger joint paint grade trim. They would not waste the wood and do all the extra work if they could just glue end grain to end grain and get a decent joint.

If you can't already tell, I think the video is just nonsense. Nothing useful to be gained from it. Don't glue to end grain if you can possibly avoid it. You will regret it if you do.

[Mark Bolton]

What we will see next is a video trying to disprove picture framing a band around an end grain cutting board because the end grain picture frame will hold back the massive expansion and contraction of the field.

https://makemesomethingspecial.com/wp-content/uploads/2018/05/frames-oak-end-grain-chopping-board.jpeg

[Edwin Santos]

I have made countless picture frames with mitered 45 degree corners. Even before time for expansion contraction, drop it on the floor and the joint will separate at the glue line...hence the reason for splining joints.

Do you think there is a difference between a glue joint's resistance to shock (like your drop test, or a mallet pounding) versus progressively applied force (like the video author is using, or say mass/gravity over time, or expansion/contraction)?

The subject of a Domino joint's resistance to shock load came up in another recent thread so it was on my mind.

Perhaps a particular glue joint or a particular glue will respond well to one kind of load and not the other.
I don't believe I've ever seen anyone test the particular issue I'm describing.

[Frank Pratt]

What we will see next is a video trying to disprove picture framing a band around an end grain cutting board because the end grain picture frame will hold back the massive expansion and contraction of the field.

I would not be in the least bit surprised if someone posted a link in this thread to just such 'proof' :)

As far as the video this thread is regarding, he has good methodology and video quality, but he's just demonstrated what most anyone that's worked with wood for a few years already knows. He just presented it in a manner that would, shall we say, generate clicks. Not a statement of his intent, just the optics of it.

[Edwin Santos]

What we will see next is a video trying to disprove picture framing a band around an end grain cutting board because the end grain picture frame will hold back the massive expansion and contraction of the field.

https://makemesomethingspecial.com/wp-content/uploads/2018/05/frames-oak-end-grain-chopping-board.jpeg

Mark, here's a funny story for you.
Once at an arts fair, I encountered a table where a woodworker was selling cutting boards and cheese boards just like the picture.
I squared up my shoulders and walked up to him like a gunslinger and challenged his work over the obvious expansion/contraction shortcomings.
He proceeds to tell me the exposed end grain was 1/8" veneer sliced on a large bandsaw, run through a wide belt sander, glued up over two pieces of baltic birch, and then wrapped with the mitered frame. Then he winks and asks me if I want to buy a high priced Baltic Birch cutting board.

I hung my head, laid the fiddle at his feet and walked out of the octagon.

[Mark Bolton]

I hung my head, laid the fiddle at his feet and walked out of the octagon.

Ive seen the same several times however, a drum with a head beaten so much its in tatters, you still see the solid wood execution almost daily if you check in on any of the "sale" sites. It even happens here at the shop occasionally with people stopping in to show off their latest creation. I use to try to give some input, now I just say "wow, thats beautiful" and they simply must learn the hard way.

Not that I make cutting boards but in my world pulling a "con" on someone thinking they are getting a solid end grain cutting board wouldnt fly. The minute they were made aware of "plywood" it would be set back down.

But all the power to anyone who rationalizes however they choose to part their customer from their funds.

[Edwin Santos]

Not that I make cutting boards but in my world pulling a "con" on someone thinking they are getting a solid end grain cutting board wouldnt fly. The minute they were made aware of "plywood" it would be set back down.

But all the power to anyone who rationalizes however they choose to part their customer from their funds.

Well you pretty much summed up the entire post WWII commercial furniture industry.
I'm not arguing with you. At the time I thought it was clever woodworking and it didn't occur to me that his creativity might be unethical to some.

[Mark Bolton]

Well you pretty much summed up the entire post WWII commercial furniture industry.
I'm not arguing with you. At the time I thought it was clever woodworking and it didn't occur to me that his creativity might be unethical to some.

I dont disagree. No one in this day and age "needs" a full thickness end grain cutting board. No one is butchering whole or quartered animals with a 5lb cleaver and needs the forgiveness of the end grain. So the veneer is a far better capitalization of resources for an esthetic board. Makes total sense. I suppose in hind sight it all comes down to a price point. True end grain board is $xxx.xx, faux is $xx.xx. Is what it is.

Im not a purist. I could care less as long as the customer is happy and its not crap that is fatally flawed from the get go. And now, who cares about that... hopefully the fatally flawed get sued or fold up with returns/complaints. I guess thats the post war law of the land you speak of.

[andrew whicker]

Millions upon Millions of face frames use edge to side grain on glue up.

[johnny means]

Millions upon Millions of face frames use edge to side grain on glue up.

Of course, it helps that the entire face frame assembly is glued to another object.

[andrew whicker]

Many of you are really reaching to find something wrong with his experiment, but deflecting to entirely different subjects.

- "But what about wood movement over time?"

Notice he never mentioned this. The thing he was set to disprove was quotes that he showed at the very beginning, like this one: "Any joint that butts End grain to End grain will be weak because you're gluing wood fibers at their porous ends instead of along their sides."

He completely proves that to be wrong. Notice that quote said nothing about "well, obviously wood growth is a huge issue and that's why you can't glue end to end".

- "who would glue up two boards with the same exact geometry in real life?"

How else do you test something other than using the same scenarios to understand their relative nature? Why would you compare a 12" side to side joint to a 3" end grain joint? What would that prove?

[andrew whicker]

The side panel is glued and screwed to the stile, not the rail.

[Mark Bolton]

Many of you are really reaching to find something wrong with his experiment, but deflecting to entirely different subjects.

I think the point thats trying to be made is one thats been made over and over but for whatever reason people want to fight it... the glue joint itself is for the most part a fixed entity trying to constrain the wood which is a non fixed entity. So trying to defend the integrity of a glue joint in any capacity really solves nothing because all your doing is trying to push the boundaries of the joints capacity as far as possible without experiencing a failure when the real issue is, just adjust your practice as to not push the joint close to failure (to avoid a failure/callback/return/customer complaint/wife complaint/whatever).

Endgrain to endgrain is a disaster just as stated in regards to gluing 2 2x10's together end to end and walking out over a 50' drop. You'd never do it. Strip laminated plank, Id walk out there all day. The video doesnt really achiever anything other than in the most delicate/light of situations where someone may glue endgrain to endgrain and it shows clearly that that joint is extremely brittle (ever chiseled glue off your bench? its like glass? same brittle in an endgrain glue up).

It just becomes common sense.. but if you have to learn things the hard way have at it.

[Stan Calow]

I think it was a good engineering test for one very specific mode of failure, and wasn't intended to cover all possible joinery scenarios. I too have alway heard, from magazines, books, videos, TV, etc., that end-to-end was always a weak bond. The rest of the stuff about long-term movement, bending, and sharp impacts, are all other things that can be tested and reported as well, but doesn't invalidate this specific, basic study. And its not always necessary or wise to have the strongest possible joint in the world.

[Doug Garson]

The video doesnt really achiever anything other than in the most delicate/light of situations where someone may glue endgrain to endgrain and it shows clearly that that joint is extremely brittle.

It just becomes common sense.. but if you have to learn things the hard way have at it.

Not true, the side grain joints failed in the wood at lower forces than the end grain glue joint failed in the glue. So the end grain glue joint is stronger than the side grain wood but not as strong as the long grain wood. Thus the strength ranking is
1- long grain wood,
2- end grain glue joint and
3- side grain wood.

[Mike King]

Miter joints are end grain to end grain…

[Lee Schierer]

I was at a wood show a number of years ago. There was a booth selling Hi-Pur glue that glued up samples of wood using their glue. The joints were all end grain to end grain. Shortly after gluing the pieces together they would hand the samples to people and challenge them to break the joint. None of the joints failed. It was obviously a very strong glue. The problem is that Hi-Pur glue is expensive.

From my own experience, I read an article about failure of miter joints. The thing that stuck in my mind was that miter joints are essentially end grain joints. The article suggested that the reason for most failures was glue starvation due to the grain pulling the glue out of the joint. By simply coating both sides of the joint with glue prior to assembly, they demonstrated that the joints were 2-3 times stronger than the same wood joint with glue applied to only one side. My experience has confirmed that practice.

With regard to the video, his conclusions were valid, BUT, that doesn't mean that 99% of woodworkers are wrong. We don't use end grain to end grain joints where maximum strength is required for load bearing because as the video showed, long grain without any joint is 6-8 times stronger than any glue joint. Can I glue up a checker board with squares of walnut and maple and expect it to be strong enough for a checker board, it certainly will. Would I use and end grain joint is a structural application, certainly not.

[Mark Bolton]

Millions upon Millions of face frames use edge to side grain on glue up.

This is true and the way we do it with pocket screws like many others. But if youve ever had the need due to a customer change to pop out a rail on a faceframe thats already assembled and finished you'd see that simply removing the pocket screws and with a very small mallet and a light/sharp tap, the rail (end grain to long grain) pops free like a charm and comes out completely clean. Whether you double coat the end grain or not and end grain joint just doesnt have the cellulose/cellulose surface area contact that a long grain joint does.

I think he even states it in the video and its just common sense. A board is just a bundle of straws. Glue up a bundle of straws and lay two bundles side by side and glue them together. Take two more and glue them end to end. The contact area end to end is just where the ends of the straws touch. The remaining area is filled with brittle glue that is simply glued to itself. PVA isnt as brittle as CA but scraping of your bench top is plenty brittle enough to leave a shard that will send you to the first aid kit for a bandaid which is why a sharp tap with a mallet breaks the rail/stile free on the faceframe. Its just shearing the brittle glue line because there is very little cellulose/cellulose surface area glued.

Ive dropped several faceframes in the shop and even pocket screwed the joints will separate with a very light drop.

[Jim Dwight]

I do not find fault with the technique he is using to do his tests. I find fault with his premise that what we care about is integrity immediately after glueup. I don't make things to last a few minutes or days. He pretends to have proven that end grain joints are strong and reliable. But he doesn't address wood movement so he hasn't proven anything useful at all.

If he wants to do a meaningful test of his premise he needs to address wood movement. Change the moisture level in the wood pieces and see what happens. I am confident I already know what will happen.

He succeeded to get us to watch his video and comment about it so he probably got what he wanted.

[Edward Weber]

Nothing new, nothing discovered, nothing debunked, absolute nonsense.
As has been stated by some, he presents his findings in a distorted way, as to make it seem to contradict what we all consider common knowledge about glue joints.

The saddest thing to me is that there are 5.6k people that liked this video.
I won't go into what joint is or isn't strong, I'll only say that pva glues have proven to perform incredibly well if used correctly with proper joinery and construction techniques.

[Kevin Jenness]

But if youve ever had the need due to a customer change to pop out a stile on a faceframe thats already assembled and finished you'd see that simply removing the pocket screws and with a very small mallet and a light/sharp tap, the stile (end grain to long grain) pops free like a charm and comes out completely clean.

Interesting observation, and completely contrary to my experience. When I have dismantled pocket screwed frames after a couple of minutes they almost always tear the side grain out. Perhaps the difference is in the wood species used?

I wouldn't rely on an unreinforced end grain joint as seasonal wood movement would likely break it loose over time, but despite my initial skepticism I have come to rely on pocket screws with glue for face frame joinery.

[Mark Bolton]

But if youve ever had the need due to a customer change to pop out a stile on a faceframe thats already assembled and finished you'd see that simply removing the pocket screws and with a very small mallet and a light/sharp tap, the stile (end grain to long grain) pops free like a charm and comes out completely clean.

Interesting observation, and completely contrary to my experience. When I have dismantled pocket screwed frames after a couple of minutes they almost always tear the side grain out. Perhaps the difference is in the wood species used?

I wouldn't rely on an unreinforced end grain joint as seasonal wood movement would likely break it loose over time, but despite my initial skepticism I have come to rely on pocket screws with glue for face frame joinery.

Its all Ive ever used (pocket screws on 1.5" face frames, glued. Ive done this with several species because unfortunately it seems in my world people decide they want something like a trash pull out after the fact so your left knocking out a rail or rail and stile to make a full height opening where a door/drawer was. Not sure about your method whether your levering them apart or what but a sharp vertical tap (up or down) shearing the glue line and every one Ive ever had to do comes out clean as a whistle other than a light scuff, filling screw hole, and a bit of finish. Most glue/adhesive joints Ive ever dealt with are very weak in shear for all the reasons mentioned in these type of threads.

[Doug Garson]

Nothing new, nothing discovered, nothing debunked, absolute nonsense.
As has been stated by some, he presents his findings in a distorted way, as to make it seem to contradict what we all consider common knowledge about glue joints.

The saddest thing to me is that there are 5.6k people that liked this video.
I won't go into what joint is or isn't strong, I'll only say that pva glues have proven to perform incredibly well if used correctly with proper joinery and construction techniques.
Mind explaining how he "presents his findings in a distorted way"? Seems to me he presented his findings in a neutral way. He glued up the samples, let the glue cure, tested to failure, recorded the results and displayed them in a straightforward graph.

[Frank Pratt]

Mind explaining how he "presents his findings in a distorted way"? Seems to me he presented his findings in a neutral way. He glued up the samples, let the glue cure, tested to failure, recorded the results and displayed them in a straightforward graph.

My issue was with how he intro'd the video with all kinds of hype about how he was going to turn the world's collective knowledge of wood glue on its ear. As I mentioned earlier, all he did is show us what most any experienced wood worker already knows. There was literally nothing new there.

Or maybe he's just a woodworking noob who just discovered this & wanted to share it with the world. (and get beaucoup views) :)

I have no problem at all with his testing methodology. Indeed, it was very good.

[Edward Weber]

He proved nothing other than wood glue is stronger than most wood along the grain and not as strong accross the grain.
Most of us knew that already

[Doug Garson]

My issue was with how he intro'd the video with all kinds of hype about how he was going to turn the world's collective knowledge of wood glue on its ear. As I mentioned earlier, all he did is show us what most any experienced wood worker already knows. There was literally nothing new there.

Or maybe he's just a woodworking noob who just discovered this & wanted to share it with the world. (and get beaucoup views) :)

I have no problem at all with his testing methodology. Indeed, it was very good.
I just rewatched the intro, I found it pretty lowkey, no mention of turning anything on its ear. He just repeats what everyone thinks that end grain glue ups are useless and a rookie mistake, asks is it true then says he's going to measure it.

[Rich Engelhardt]

But if youve ever had the need due to a customer change to pop out a stile on a faceframe thats already assembled and finished you'd see that simply removing the pocket screws and with a very small mallet and a light/sharp tap, the stile (end grain to long grain) pops free like a charm and comes out completely clean.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Interesting observation, and completely contrary to my experience. When I have dismantled pocket screwed frames after a couple of minutes they almost always tear the side grain out. Perhaps the difference is in the wood species used?

I wouldn't rely on an unreinforced end grain joint as seasonal wood movement would likely break it loose over time, but despite my initial skepticism I have come to rely on pocket screws with glue for face frame joinery.Kevin's experience is the same as mine. Pocket screws & glue are a bear to take apart.

[Edward Weber]

Mind explaining how he "presents his findings in a distorted way"? Seems to me he presented his findings in a neutral way. He glued up the samples, let the glue cure, tested to failure, recorded the results and displayed them in a straightforward graph.


There is no MYTH to debunk.
This is not a myth or folklore it's science, plain and simple. The properties of PVA glue, the structure of wood and it's orientation all combine to make it so that some joints are strong and some are not as strong. Woodworkers learn about this or should, very early on.

The beginning of the distortion comes by putting forward a false premise, to claim to have solved some type of problem or issue that needed attention.
His premise is that the common perception about end grain to end grain wood joints being weak is incorrect. Spoiler alert, they are.
Before you launch into a "scientific experiment" as many have called this, you first need to know if it's been done or if it's necessary to be done.
We already know the strength of PVA glues.
We already know that wood breaks with the grain easily
We already know that wood is difficult to break accross the grain
So what point does this testing prove?

He titles his video "glue myths" but mainly tests wood strength.He performs his experiments and presents his findings in a way that makes it sound as if there is something new to be learned, there is not.
I suppose I should say I learned nothing new.

Maybe this is all new to him and his subscribers, I don't know.
Sadly the number of people who liked this video for whatever reason continues to grow. Many of the positive comments have come from popular woodworking personalities and people who should know better.
I find the video and the discussions surrounding it disappointing, even my part in it.
Wood glue is to assist joinery not replace it, build wisely.
JMHO

[Mark Bolton]

Many of the positive comments have come from popular woodworking personalities and people who should know better.

They dont care about woodworking and they do know better but cash is king so they are fine with the masses following flawed practices as long as it fattens the bottom line. Spagnolo is in that string and should be the first one to be a voice of reason but he doesnt even know which end of a dovetail drawer the pins and tails go on so why would he care about flawed glue logic.

Sadly you just have to let the failures teach their lessons.

[Doug Garson]

I, for one, learned that an end grain joint is stronger than the wood with the grain. I expected the end grain joint to fail in the glue but at a much lower load than the wood with the grain. If you already knew that then good for you. Having said that I'm not going to run out and use an end grain joint in a structural component but I don't think he suggests that. I don't find the discussion disappointing at all, two best way to learn are discussions and doing stuff.

[Eric Arnsdorff]

I, for one, learned that an end grain joint is stronger than the wood with the grain. I expected the end grain joint to fail in the glue but at a much lower load than the wood with the grain. If you already knew that then good for you. Having said that I'm not going to run out and use an end grain joint in a structural component but I don't think he suggests that. I don't find the discussion disappointing at all, two best way to learn are discussions and doing stuff.

I agree completely!

He actually points out the things we all know which is wood is very weak when stressed parallel to the long grain of the wood.

Based on everyone saying not to join end grain that I assumed it wasn’t “strong” .

However, what he did show is that an end grain to end grain joint is stronger than long grain to long grain joint. This means an end grain to end grain joint is equivalent to turning wood in it’s weakest direction.

Also, I will use glue for end grain to end grain because it does provide some strength even if I would’ve thought it was weaker than long grain to long grain. He showed it is actually stronger.

This doesn’t change the fact that long grain to long grain is the weakest direction to load wood. What he is showing is that an end grain to grain joint is only slightly better than loading the wood in its weakest direction.

The end result doesn’t change how anything is done. I wouldn’t put a narrow piece of wood in a place to carry any load that relied on the long grain to long grain strength. The end grain to end grain joint is still weak in comparison to the bending strength in wood’s strongest direction.

[Mike Henderson]

In my experience, most furniture glue joints fail over time due to repeated expansion - contraction. The edge/end joints he shows will certainly fail this way. I have made countless picture frames with mitered 45 degree corners. Even before time for expansion contraction, drop it on the floor and the joint will separate at the glue line...hence the reason for splining joints. There are many reasons for end grain scarf joints and mortised face frame corners beyond endgrain joint strength. Most involve resistance to expansion/contraction shear forces.

That's been my experience, also. For any end grain joint you need some "help" such as a spline.

Mike

[Bob Cooper]

Well I thought the guy took extreme care to be objective and was super low key. As an engineer I thought his approach was well thought out and well instrumented. I can’t find a fault with anything he did and would encourage him to keep exploring. I for one would not have predicted his results. 10 out of 10 in my bool

[Christopher Wellington]

I think the holistic view of this question would consider the strength of the wood around the joint as much as the strength of the joint. Both, incidentally, impacted by grain direction.

Comparing the strength of edge grain glue-ups to end grain glue-ups is an interesting question, but what matters is whether the joint is strong enough for its intended purpose. An edge grain glue up is stronger than the wood, so yeah, if a solid piece is strong enough for your bending loads across the grain, a glued-up panel will be strong enough too. The trouble with an end grain glue-up is that bending loads with the grain are often too high for a glue joint to take (e.g. you'd walk on scaffolding made from a solid long piece, but not the same piece made from two short sections glued end-to-end).

[Bob Cooper]

Be interesting to see if seasonal movement made any difference in his tests.

[Brian Holcombe]

Most woodworking projects are engineered for longevity rather than ultimate strength. Traditional joinery provides longevity and it can provide demountability if it is planned in at the start.

This is a neat video, perhaps it is worth putting a little glue on the end grain in a long run of dovetails with wide spacing, but I would not think it wise to rely upon an end grain glue up that does not otherwise have reinforcement.

[Stan Calow]

Be interesting to see if seasonal movement made any difference in his tests. In which case, since the grain is all running in the same direction by definition, it shouldn't be an issue, right? But I think people are assuming the test applies to mitered end grain joints, which is not at all the point. He's testing the strength of the glue/grain orientation, not woodworking joints. I saw no recommendations regarding applying this information. The more interesting part of this to me is the verification that long-grain to long-grain is weaker, but certainly not enough to stop using that kind of joinery.

[mreza Salav]

I, for one, learned that an end grain joint is stronger than the wood with the grain. I expected the end grain joint to fail in the glue but at a much lower load than the wood with the grain. If you already knew that then good for you. Having said that I'm not going to run out and use an end grain joint in a structural component but I don't think he suggests that. I don't find the discussion disappointing at all, two best way to learn are discussions and doing stuff.

I have the same thought. Not that I'll use end-to-end joints from now on but I didn't expect the breaking point in the video to be larger than side-to-side.
I doubt many of those here who "claim" there was nothing new here and are so critical of the video knew this as well; they just don't want to admit it.

[Edward Weber]

I have the same thought. Not that I'll use end-to-end joints from now on but I didn't expect the breaking point in the video to be larger than side-to-side.
I doubt many of those here who "claim" there was nothing new here and are so critical of the video knew this as well; they just don't want to admit it.


Well I've known glue is stronger than side a grain joint for decades.
https://www.youtube.com/watch?v=84Bx8-xBCxg
I've also known that an end grain joint will break at the glue line.
Just as he showed in the video. Nothing new

This is just bad science.
“The wood always splits before the glue fails”.
What this should tell you, is that the breaking strength of the glue joint is higher than the breaking strength of the wood in that orientation (side grain) which is x,
”On average, end to side joints were about 20% stronger than side to side."
X + 20%
“End grain joints were the strongest joints of all”
There is no way to know if end grain joints are strongest due to the fact that the side grain test and the end to side tests both failed before the actual joint strength could be measured. All you know for certain is that end grain joints fail at y. You can not claim to know or declare which is stronger, since in two of the three tests to be compared, the testing material routinely fails before a strength measurement of the glue joint could be taken. All you can prove, is that wood glue is stronger than x or x + 20%.
You could say end grain joints, y are stronger than x or x + 20% but that’s it. Anything else is pure speculation.
There is no myth

[Robert Hayward]

Here is a good video by Stumpy that further explains the glue myth video. https://www.youtube.com/watch?v=dwLWmoGh59g

[Paul Bent]

That stumpy video helped me further understand.

[Doug Garson]

The wood whisperer also commented on the video.
https://www.youtube.com/watch?v=Fuvq0FDsUC0

[Scott Brodersen]

The most important takeaway from the video is that the glue is stronger than lignan. Lignan is the natural stuff found between the wood fibres -- it adheres the fibers. Lignan is umpteen times weaker than the fibers -- this explains why wood is strong when bent along the grain and weak when bent across the grain.

This is not new knowledge though. In the early 90's when I was in school I took a wood engineering course (structural design using lumber) and we were taught the difference between the structural properties of wood along the grain (strong) and cross grain (weak). The difference was explained by the weakness of the lignan compared to the strength of the fibres. We were also taught that wood glue bonds fibres stronger than lignan does, but the glue is still weaker than the wood fibers.

So, an end-to-end glued joint will fail at the joint because at the joint there is no continuity of wood fibres -- there is only glue between the fibres at the joint. The joint is way weaker than the fibres so it fails first. Compare that to a long-grain to long-grain glued joint -- there is fibre continuity from end to end so it is still strong along the grain. Bend it across the grain it will likely break not at the glued joint but somewhere else between the fibres, because the lignan is weaker than the glue.