The Showdown

[Slackbunny]

Adam brought up the glue issue again so I'm going to add what I, let's say, believe. 

Modern glues are great for holding 2  or 3 pieces of wood together but most of them need low clamp pressure and some work better if the clamp pressure is almost non-existent, epoxy being one.  That means that if your clamp pressure is too high then you will have a starved glue joint and that is not good.  Essentially then you will have a thin line of glue holding the 2 pieces of wood together, and perhaps as Adam is suggesting some of this glue goes into the wood on the molecular level.  Now the problem with modern glue, because it is a plastic, is that even though it is fairly elasticity, meaning it will stretch or compress quite well, it's return from being deformed by this stretching or compressing is pathetic.  Therefore this will affect how the wood springs back when being bent during the draw.  The more glue lines you have the more effect it will have on the bow.  As I can see it this is why a 2 lam bow will outperform a multi-lam bow every time, as the flightshooting records seems to prove.

There is a certain phenomenon that occurs when a very thin layer of a material is "sandwiched" for lack of a better word between two other materials. The material in the middle actually takes on the physical properties of the materials it sits between. For example if you have two steel blocks that are separated by a layer of copper that is perfectly and rigidly joined you would think that in order to pull them apart, you would need to only reach the yield strength of the copper. but what actually happens is that you need to apply a stress that approaches the yield strength of the steel even though the two steel blocks are only held together by the copper layer. This only occurs if the layer is significantly thin, and if the joining is near perfect.

I know for a fact that this phenomenon occurs with metals under transverse loads, so I wonder if it would possibly apply for a thin layer of glue between two woods? What I don't know is if this happens the same way for bending and shear loads which are far more representative of the conditions of bow laminations, and I also don't know if a glue joint is truly a good model of this situation. Its food for thought though. I'd like to get a materials scientist view on this.

[adb]

I think 2" of HHB would be enough as well Pat.  It is an incredibly strong and elastic wood.  This bow is 60" long, less than 2" wide and pulls over 70# at 30"

It's bendy handle and 70#. At 26" it would be what? 60#. Next.

[Slackbunny]

What you fail to see, Marc, is you've insulted Dave in your own answer. Alzheimer's is a serious and debilitating degenerative disease. Not funny. Certainly nothing to joke about. Several members of my family had Alzheimer's and I find your remake in very bad taste. I can't speak for Dave, but I'd like an apology. Failure to do so will only magnify your arrogance.

C'mon man, that was petty. It's all well and good to get passionate about what we do, but let's not stoop to that level. This is starting to look more like a youtube comments thread on a Dane Cook video than the Primitive Archer forum.

[PatM]

Adam you need to realize that human nature allows for black humor. Nobody has to apologize.That's how we deal with our horror for things.  Humor makes them seem more normal and harmless.
  That's why Michael J Fox can make jokes about his own illness.
 You're trying to create fights about everything now.

[PatM]

I think 2" of HHB would be enough as well Pat.  It is an incredibly strong and elastic wood.  This bow is 60" long, less than 2" wide and pulls over 70# at 30"

It's bendy handle and 70#. At 26" it would be what? 60#. Next.

Case in point, this. Marc is just showing material properties here. You can learn from this.

[adb]

OK, guys. I give up. If you think Alzheimer's is funny, carry on. I don't. I got to see it first hand over 25 years in the medical world. IMO, nothing to joke about, and then justify as a way to deal with daily life. By the way, Michael J Fox has Parkinson's.

When you guys are ready to post some pictures of bows, just let me know. I need to step away from this for a bit. Too much talking and not enough working on bows. Good luck guys! I mean that.

[PatM]

OK, guys. I give up. If you think Alzheimer's is funny, carry on. I don't. I got to see it first hand over 25 years in the medical world. IMO, nothing to joke about, and then justify as a way to deal with daily life. By the way, Michael J Fox has Parkinson's.

When you guys are ready to post some pictures of bows, just let me know. I need to step away from this for a bit. Too much talking and not enough working on bows. Good luck guys! I mean that.

 You have an amazing ability to take things  the wrong way. People approach things differently. 25 years in the medical world should tell you that.
 Nobody on here is basing a stand up act on unfortunate human circumstances.

[mullet]

Yaaawn! Do you guys have Medicinal Marijuana in Canada, yet? This makes me want to jump in and build one but I hate to waste the one nice piece of Elm I have. And anyway, I have enough of James Parker's recurves and horn bows to last me for awhile.

[blackhawk]

Geez...          I go down into the shop for a couple hours doing finish work on a killa narrow hhb bow and missed two pages...looks like I spent my time wisely,and glad I was working on a bow than reading all that nonsense...some of y'all r on a very slippery slope n crossing lines IMHO ... normally this type of thread would've been pulled by now? Why isn't it?

[mullet]

Because the whining will just start over again in another thread. This is the second thread, remember? Somebody just build the bow and let's be done with this. Or ten people can build it and wait and post them at the exact, same time and see how many recurves have to be made.

[Traxx]

Seems to me,theres been way too much talk allre :laugh:ady

[son of massey]

Adam brought up the glue issue again so I'm going to add what I, let's say, believe. 

Modern glues are great for holding 2  or 3 pieces of wood together but most of them need low clamp pressure and some work better if the clamp pressure is almost non-existent, epoxy being one.  That means that if your clamp pressure is too high then you will have a starved glue joint and that is not good.  Essentially then you will have a thin line of glue holding the 2 pieces of wood together, and perhaps as Adam is suggesting some of this glue goes into the wood on the molecular level.  Now the problem with modern glue, because it is a plastic, is that even though it is fairly elasticity, meaning it will stretch or compress quite well, it's return from being deformed by this stretching or compressing is pathetic.  Therefore this will affect how the wood springs back when being bent during the draw.  The more glue lines you have the more effect it will have on the bow.  As I can see it this is why a 2 lam bow will outperform a multi-lam bow every time, as the flightshooting records seems to prove.

There is a certain phenomenon that occurs when a very thin layer of a material is "sandwiched" for lack of a better word between two other materials. The material in the middle actually takes on the physical properties of the materials it sits between. For example if you have two steel blocks that are separated by a layer of copper that is perfectly and rigidly joined you would think that in order to pull them apart, you would need to only reach the yield strength of the copper. but what actually happens is that you need to apply a stress that approaches the yield strength of the steel even though the two steel blocks are only held together by the copper layer. This only occurs if the layer is significantly thin, and if the joining is near perfect.

I know for a fact that this phenomenon occurs with metals under transverse loads, so I wonder if it would possibly apply for a thin layer of glue between two woods? What I don't know is if this happens the same way for bending and shear loads which are far more representative of the conditions of bow laminations, and I also don't know if a glue joint is truly a good model of this situation. Its food for thought though. I'd like to get a materials scientist view on this.

Wow, that is an interesting thing you describe. When separated how do the metals, well, come apart?

Metals are a little squishy when it comes to surface chemistry-they take charges easily, electrons get shuttled all over, and there is the alloying process to deal with. Organic based materials do behave differently. I think it is fair to suggest each glue surface will take on some attributes of the set glue, just not probably any characteristics from the other gluing surface.

[scp]

It appears that Mark was talking about himself when he mentioned Alzheimer's. It is possible to read it as referring to Dave if you want to do so. That would say more about the reader than about Mark.
I never make bows heavier than 50# but if someone just post an oak bow 50# heavy and 60" long with a stiff handle and tell us how wide its limbs are, I guess I can make a bow with limbs double wide to meet the challenge. I would split the bow into two 50# ones later on. Better yet, why don't we just tape up two bows 50# heavy and 60" long side by side and declare that the challenge has been met?

[Cameroo]

Eddie, don't put all us canucks in the same basket.  Some of us are content to just shake our heads and carry on with our day... 

I think the possibility of anything positive coming from this thread got lost over 100 posts ago.

[mullet]

Eddie, don't put all us canucks in the same basket.  Some of us are content to just shake our heads and carry on with our day... 

I think the possibility of anything positive coming from this thread got lost over 100 posts ago.

;)I agree.