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kubasa Member
Joined: 13 Sep 2007 Posts: 212
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Posted: Tue Dec 19, 2017 11:42 pm Post subject: Maple plate joint glue |
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So as not to hijack the other post which is slightly different I decided to start a new thread. When I plane down my maple billet book ends, I end up with a shiny, smooth surface - eventually. Knock on wood since I've never had major problems with back plate joints separating but at a microscopic level, what is going on with the glue? With the spruce, I know that a fair amount is soaking in and creating a strong bond between the two pieces. However, with maple, how much soaking in is really going on to create the bond or are we relying more on the glue strength? If that is the case, are bonds on the maple book or billet ends weaker than with spruce? The reason I ask this is because it always seems like I'm gluing glass together because my maple is literally shiny from planing and there doesn't seem to be much of a porous surface for the glue to soak in.
Sorry for a rather odd observation that is probably insignificant in the scheme of things but it's one of those curiosities that I've often wondered about.
James |
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Michael Darnton Moderator
Joined: 23 Mar 2007 Posts: 1281 Location: Chicago
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Posted: Wed Dec 20, 2017 9:31 am Post subject: |
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The theory is that glue is stronger than wood, however I've never seen a maple joint that wouldn't break on the glue joint. Because of that contradiction with "lore" I share your curiosity about this.
I do know that unlike epoxy and white/yellow glues, hide glue depends on glue sinking into the pores, not an actual glue line. I know that too much heat, too fast to the clamps, and too much pressure makes for a joint that will fail because all of the glue is squeezed out. Such a failed joint looks obviously bare of glue. White/yellow glues always have a skin of glue in the joint that can be seen and peeled off, no matter how good the joint and how tight the clamping.
I know that the old Cremonese makers scratched the joint with something like a toothed plane blade used carelessly diagonally all over the joint to rough it up before gluing, so they must have had problems, to need to think of doing that, and when I remember, I also do it. I don't know if they were trying to break the glaze you mention or whether it was to provide some space in the joint so that all of the glue wouldn't get squeezed out.
Some people speculate that the old joints aren't glued with hide glue, because very few of them have failed over time---very few. relative to later makers' joints. The usual suspect for a substitute is casein glue. _________________ new blog at my site! http://darntonviolins.com/blog
my work sites: http://darntonviolins.com and http://darntonhersh.com |
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kubasa Member
Joined: 13 Sep 2007 Posts: 212
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Posted: Thu Dec 21, 2017 12:30 pm Post subject: |
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Thanks Michael. I hadn't realize the part about about the old Cremonese makers roughing up the surface a bit. It makers sense. I might have to try that myself. This question always comes to mind every time I glue up the maple billet or book ends and then I move on and forget about it. |
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byacey Member
Joined: 29 Mar 2008 Posts: 105 Location: Edmonton, Alberta
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Posted: Fri Dec 22, 2017 1:40 pm Post subject: |
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Perhaps introducing scratches into the gluing surface tears the wood fiber enough to help the glue soak into the end capillaries of the fiber, allowing for a stronger joint.
Michael, have you ever utilized casein for a center joint? I wonder if the surface treatment would be the same as for hide glue? _________________ Bill |
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Michael Darnton Moderator
Joined: 23 Mar 2007 Posts: 1281 Location: Chicago
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kubasa Member
Joined: 13 Sep 2007 Posts: 212
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Posted: Fri Dec 22, 2017 2:25 pm Post subject: |
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byacey wrote: | Perhaps introducing scratches into the gluing surface tears the wood fiber enough to help the glue soak into the end capillaries of the fiber, allowing for a stronger joint.
Michael, have you ever utilized casein for a center joint? I wonder if the surface treatment would be the same as for hide glue? |
Bill, is that you - my fellow Ukrainian friend? I don't make it over to the other forum much so we haven't conversed in a while. Hope all is well. Have a Merry Christmas.
James |
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byacey Member
Joined: 29 Mar 2008 Posts: 105 Location: Edmonton, Alberta
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Posted: Fri Dec 22, 2017 9:56 pm Post subject: |
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Tis' I indeed! Merry Christmas!
I just finished fighting off a bout of the flu; somewhat back to my (ab)normal? self.
Just got back from procuring some wheat this afternoon to make Kutya for Christmas eve. _________________ Bill |
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kubasa Member
Joined: 13 Sep 2007 Posts: 212
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Posted: Sat Dec 23, 2017 10:04 pm Post subject: |
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Glad your back to health. Kutya is wonderful stuff. Enjoy! I'm sure my Dad will have a large bowl prepared as always. |
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