Page 2 of 2 FirstFirst 12
Results 26 to 48 of 48

Thread: The real glue strength

  1. #26

    Default Re: The real glue strength

    If glue has nothing to with sound transfer, then how could a good fitting joint with a bolt. Fender has been doing it for years, Taylor too maybe? There are some Mandolin Builders that build very nice sounding nice quality mandolins with bolt on necks. In my case it was insurance, because the joint is no longer dovetailed, itís more of MT joint now.

  2. #27
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    8,236
    Blog Entries
    4

    Default Re: The real glue strength

    Quote Originally Posted by ProfChris View Post
    The tested "strength" of a glue joint is usually pretty irrelevant. With good mating surfaces, what normally fails is the wood itself rather than the glue line coming apart.

    For instrument building, far more important are the potential failure modes of a glue joint and its repairability and usability for that application.

    Failure modes:

    1. Impact - If you want to resist this then brittle glues are not for you. Sledge runners might be an example.

    2. Heat - PVAs, Titebond, even epoxy tend to soften with heat, and re-set afterwards. This is a known problem with instruments left in hot cars, which can come out a different shape!

    3. Cold creep - if the stresses are trying to slide the glue line sideways, PVAs and Titebond can allow this over time. Hide glue doesn't. I don't know about epoxy, I suspect different formulations behave differently.

    Repairability and usability:

    1. Hide glue is the only (so far as I know) easy glue for disassembly and reassembly, because fresh glue reactivates the old glue.

    2. Working time is important - hide glue gives you seconds, maybe a minute or two if the parts are heated. But it reactivates with heat and moisture, so I like it for assembling bodies because I can finesse any slight gaps.

    3. Moisture and wood movement. Fingerboards tend to curl up from moisture in glue (not good), so some people prefer epoxy for these joints.

    4. Wicking into gaps - CA glue is especially good at this, helpful for lifting frets, plastic binding, etc.

    And so on, and so on ...

    Each builder finds the combination of glues which fits with how they like to work, so there is no consistency. If I could only ever use one glue I guess it would be hot hide glue, though Titebond Original would also be an option.

    I'd say there is one consistency though - strength of glue joint is rarely a consideration in choosing glue (excepting Pritt stick and flour and water paste, though I've read that rice flour paste is used in some Japanese woodworking!).
    Can you site any study showing that epoxy bonds soften with heat and then re-harden? I'm not saying it doesn't happen but in my experience Ive never seen it happen. As you no doubt know epoxy is held together by covalent bonding and I don't see how they can "soften"?
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  3. #28
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    8,236
    Blog Entries
    4

    Default Re: The real glue strength

    Quote Originally Posted by justrythym View Post
    Thanks Man! For the record?....this joint is not really as sloppy as it sounds. Top was crushed in, dovetail broken, rear block broken too. My Son bought this for me to repair. I put a red spruce top on it and it’s ready for the neck. The neck is quite thin. If the joint fails I’m going to just put a new neck from scratch on it. Thus the question of the one time strength deal.
    why don't you put up a pic of what you are trying to fix???
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  4. #29
    Registered User Inklings's Avatar
    Join Date
    Jun 2016
    Location
    North Shore of Masschusetts
    Posts
    119

    Default Re: The real glue strength

    Quote Originally Posted by sunburst View Post

    No single glue or adhesive is best for all different situations. .
    Yep.
    Kirby Francis

    Francis Guitar Repair

  5. #30
    Registered User
    Join Date
    Oct 2007
    Location
    Davison Mich.
    Posts
    443

    Default Re: The real glue strength

    just my opinion, but if I were to use hide, it would only be for the back, to be able to get at everything else, I doubt I would ever use it on joining plates, , but on the other hand heat seems to work on about anything you need to take apart

  6. #31
    Registered User
    Join Date
    Jan 2009
    Location
    S.W. Wisconsin
    Posts
    5,446

    Default Re: The real glue strength

    The main reason for me to use hide glue is the fact that - if for any reason something has to come apart or be fixed, hide glue will bond to itself. Other glues will have a weaker joint the second or any succeeding repairs. There are some repairs that are normal and will have to be done in the life of the instrument. Maybe more than once. Fingerboard is one that may wear out if played a lot.
    THE WORLD IS A BETTER PLACE JUST FOR YOUR SMILE!

  7. #32
    Teacher, luthier
    Join Date
    Oct 2017
    Location
    Southeast Tennessee
    Posts
    1,585

    Default Re: The real glue strength

    I have just removed the back from a Goya 12 string guitar, and am preparing to remove the huge plywood bridge plate and re-profile and re-locate some of the braces so I can turn it into a good instrument.

    I've opened a few backs before, and all but one were originally assembled with hide glue. The back on this one was assembled with white PVA glue, and took it much more time and care to get it off cleanly. I'll put it back on with hide glue. I'll probably also use it for the new bridge plate and any braces that I move or replace.

    After 20+ years of instrument work, I think my choices through carefully. As has already been said, "The right glue for the right job."

    I use 6 glues in the shop: Hot hide glue and Titebond Original for general carpentry; liquid hide glue for frets, nuts, and occasional low stress joints; Wilsonart Melamine glue and Duco cement for plastic bindings; and CA, mostly for patching fingerboards and filling nut slots. The longer I do this work, the less often I use CA.

    I always keep in mind that the next person who works on the instrument does not need to struggle with the consequences of a bad glue choice.

    Click image for larger version. 

Name:	ts4-front.jpg 
Views:	38 
Size:	1.82 MB 
ID:	183971Click image for larger version. 

Name:	ts4-back.jpg 
Views:	35 
Size:	1.50 MB 
ID:	183970

    The stains are from the removal process. They will be sanded out before re-assembly.
    Last edited by rcc56; Mar-03-2020 at 7:41pm.

  8. The following members say thank you to rcc56 for this post:


  9. #33
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    8,236
    Blog Entries
    4

    Default Re: The real glue strength

    Quote Originally Posted by rcc56 View Post
    I have just removed the back from a Goya 12 string guitar, and am preparing to remove the huge plywood bridge plate and re-profile and re-locate some of the braces so I can turn it into a good instrument.

    I've opened a few backs before, and all but one were originally assembled with hide glue. The back on this one was assembled with white PVA glue, and took it much more time and care to get it off cleanly. I'll put it back on with hide glue. I'll probably also use it for the new bridge plate and any braces that I move or replace.

    After 20+ years of instrument work, I think my choices through carefully. As has already been said, "The right glue for the right job."

    I use 6 glues in the shop: Hot hide glue and Titebond Original for general carpentry; liquid hide glue for frets, nuts, and occasional low stress joints; Wilsonart Melamine glue and Duco cement for plastic bindings; and CA, mostly for patching fingerboards and filling nut slots. The longer I do this work, the less often I use CA.

    I always keep in mind that the next person who works on the instrument does not need to struggle with the consequences of a bad glue choice.

    Click image for larger version. 

Name:	ts4-front.jpg 
Views:	38 
Size:	1.82 MB 
ID:	183971Click image for larger version. 

Name:	ts4-back.jpg 
Views:	35 
Size:	1.50 MB 
ID:	183970

    The stains are from the removal process. They will be sanded out before re-assembly.
    Good post! I was interested in your comment about using liquid hide glue on frets -- so LHG will hold metal frets in place? That is great info -- I need to glue in three frets and I would sure like to use that instead of cyanoacrylate.
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  10. #34
    Teacher, luthier
    Join Date
    Oct 2017
    Location
    Southeast Tennessee
    Posts
    1,585

    Default Re: The real glue strength

    It holds well enough. I've used it for about 100 fret jobs over the last 20 years. I've had only maybe 5 or 6 ends lift up in that time. That's not too bad a record for 2000 frets.

    Bear in mind that pre-radiusing the fret wire is very important, and also the way you drive them.

    If your fret slots are wallowed out, you might have to crimp the tang slightly with the Stew-mac crimping tool; or if you don't have one, you can handle it the old fashioned way and put a few barbs in the back of the tang with a cheap chisel.
    Last edited by rcc56; Mar-03-2020 at 10:29pm.

  11. The Following 2 Users Say Thank You to rcc56 For This Useful Post:


  12. #35

    Default Re: The real glue strength

    Quote Originally Posted by Bernie Daniel View Post
    Can you site any study showing that epoxy bonds soften with heat and then re-harden? I'm not saying it doesn't happen but in my experience Ive never seen it happen. As you no doubt know epoxy is held together by covalent bonding and I don't see how they can "soften"?
    I've opened a few epoxy joints with heat myself! The resin softens and a spatula can slide in.

    I read that this was the way to deal with epoxy joints in a luthier forum, so I'm sure others have done it too.

    It worked, so I've never bothered looking for studies.

  13. The following members say thank you to ProfChris for this post:

    hank 

  14. #36

    Default Re: The real glue strength

    I have did my own little petty glue test, the last 48 hrs. I tested Titebond original, Titebond liquid hide and Elmers wood Max. I glued two mating surfaces of maple for each. After 48 hrs. The Titebond hide is still soft and rubbery when you stick a sharp point in it, the Elmers is soft and rubbery also. The Titebond original chips when picked with a sharp point. This tells me all I wanted to know. Hot hide glue is the glue of choice for itís hardness and repair properties. The liquid hide doesnít even come close. In my humble opinion, if you use either one of these glues I mentioned Elmers Max, or TB hide to glue a neck joint or fretboard.......itís not a matter of if it fails, itís when. Elmers Max had some killer reviews and so did TBLH. Iím not worried about being able to save this neck if the joint fails. I will put a new neck on it if that happens. The neck was really thin, had been taken down. I installed a stiffener of ironwood and used epoxy. I have decided to install the neck joint with JB Weld Wood. Maybe with that and the screw, it will hold. I enjoy reading posts from you veteran builders. I have been doing this as a hobby for about 12 years. I know just enough to be dangerous. Thanks Gentleman

  15. The following members say thank you to justrythym for this post:

    hank 

  16. #37

    Default Re: The real glue strength

    John, I have a question. I have already bound this fretboard and was planning to install frets before gluing it on the neck. The binding will need to be scraped. Should I just put it on first, scrape and then fret. Thx.

  17. #38
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    8,236
    Blog Entries
    4

    Default Re: The real glue strength

    Quote Originally Posted by justrythym View Post
    I have did my own little petty glue test, the last 48 hrs. I tested Titebond original, Titebond liquid hide and Elmers wood Max. I glued two mating surfaces of maple for each. After 48 hrs. The Titebond hide is still soft and rubbery when you stick a sharp point in it, the Elmers is soft and rubbery also. The Titebond original chips when picked with a sharp point. This tells me all I wanted to know. Hot hide glue is the glue of choice for it’s hardness and repair properties. The liquid hide doesn’t even come close. In my humble opinion, if you use either one of these glues I mentioned Elmers Max, or TB hide to glue a neck joint or fretboard.......it’s not a matter of if it fails, it’s when. Elmers Max had some killer reviews and so did TBLH. I’m not worried about being able to save this neck if the joint fails. I will put a new neck on it if that happens. The neck was really thin, had been taken down. I installed a stiffener of ironwood and used epoxy. I have decided to install the neck joint with JB Weld Wood. Maybe with that and the screw, it will hold. I enjoy reading posts from you veteran builders. I have been doing this as a hobby for about 12 years. I know just enough to be dangerous. Thanks Gentleman
    Are you sure that your glue supplies are good? Your results sound atypical to say the least? Good luck.
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  18. #39

    Default Re: The real glue strength

    Quote Originally Posted by justrythym View Post
    I have did my own little petty glue test, the last 48 hrs. I tested Titebond original, Titebond liquid hide and Elmers wood Max. I glued two mating surfaces of maple for each. After 48 hrs. The Titebond hide is still soft and rubbery when you stick a sharp point in it, the Elmers is soft and rubbery also. The Titebond original chips when picked with a sharp point. This tells me all I wanted to know. Hot hide glue is the glue of choice for it’s hardness and repair properties. The liquid hide doesn’t even come close. In my humble opinion, if you use either one of these glues I mentioned Elmers Max, or TB hide to glue a neck joint or fretboard.......it’s not a matter of if it fails, it’s when. Elmers Max had some killer reviews and so did TBLH. I’m not worried about being able to save this neck if the joint fails. I will put a new neck on it if that happens. The neck was really thin, had been taken down. I installed a stiffener of ironwood and used epoxy. I have decided to install the neck joint with JB Weld Wood. Maybe with that and the screw, it will hold. I enjoy reading posts from you veteran builders. I have been doing this as a hobby for about 12 years. I know just enough to be dangerous. Thanks Gentleman
    Hmm. Many glues don't fully cure for a long time, sometimes 7 days or more. "Dry" and "cured" are two very different things.
    So wait.. you decided that HHG was best, but will be using "JB WoodWeld" epoxy? I'm confused.

  19. The following members say thank you to Marty Jacobson for this post:

    hank 

  20. #40

    Default Re: The real glue strength

    I agree with Marty on drying time. Most bridge reglues can be strung up after the recommended 24 hours and will hold string tension fine on an acoustic guitar -- but I still give it a week -- because it costs me nothing and I'm sure it is cured.

  21. #41
    Teacher, luthier
    Join Date
    Oct 2017
    Location
    Southeast Tennessee
    Posts
    1,585

    Default Re: The real glue strength

    Liquid hide glue must be fresh. The shelf life is one year from the date coded on the bottle. I have seen expired bottles sitting on store shelves more than once.
    It is best to refrigerate it when not in use.
    It cures by evaporation, so drying time must be extended, especially if the environment is cool or humid. For the few things that I use it for, I let it dry at least 48 to 72 hours before putting the joint under stress, more during the winter or if the weather is damp.
    For fingerboards I prefer hot hide glue. For neck joints, I use hot hide glue or Titebond Original. They are both well proven.

  22. #42
    Adrian Minarovic
    Join Date
    Oct 2003
    Location
    Banska Bystrica, Slovakia, Europe
    Posts
    2,638

    Default Re: The real glue strength

    Quote Originally Posted by justrythym View Post
    I have did my own little petty glue test, the last 48 hrs. I tested Titebond original, Titebond liquid hide and Elmers wood Max. I glued two mating surfaces of maple for each. After 48 hrs. The Titebond hide is still soft and rubbery when you stick a sharp point in it, the Elmers is soft and rubbery also. The Titebond original chips when picked with a sharp point. This tells me all I wanted to know. Hot hide glue is the glue of choice for it’s hardness and repair properties. The liquid hide doesn’t even come close. In my humble opinion, if you use either one of these glues I mentioned Elmers Max, or TB hide to glue a neck joint or fretboard.......it’s not a matter of if it fails, it’s when. Elmers Max had some killer reviews and so did TBLH. I’m not worried about being able to save this neck if the joint fails. I will put a new neck on it if that happens. The neck was really thin, had been taken down. I installed a stiffener of ironwood and used epoxy. I have decided to install the neck joint with JB Weld Wood. Maybe with that and the screw, it will hold. I enjoy reading posts from you veteran builders. I have been doing this as a hobby for about 12 years. I know just enough to be dangerous. Thanks Gentleman
    Is the TBLHG soft and rubbery inside the joint or the squeeze out? You should remove excessive squeeze out glue right after clamping with stiff brush or spatula. Large bead of wet glue sitting on/near joint can take long time to dry thoroughly and in turn supply moisture back into the joint...
    But in my controlled shop smaller droplets or runs dry within 24 hour thoroughly.
    When using epoxy together with screw make sure you won't glue the screw in. That could be problem once you want to remove the neck and the screw is stuck. Even if you want to chisel the neck out you don't want to hit the screw with your chisel.
    Adrian

  23. #43

    Default Re: The real glue strength

    Quote Originally Posted by HoGo View Post
    Is the TBLHG soft and rubbery inside the joint or the squeeze out? You should remove excessive squeeze out glue right after clamping with stiff brush or spatula. Large bead of wet glue sitting on/near joint can take long time to dry thoroughly and in turn supply moisture back into the joint...
    But in my controlled shop smaller droplets or runs dry within 24 hour thoroughly.
    When using epoxy together with screw make sure you won't glue the screw in. That could be problem once you want to remove the neck and the screw is stuck. Even if you want to chisel the neck out you don't want to hit the screw with your chisel.
    Thanks HoGo, I appreciate that. The glues I tested were just small amounts. They really should have been harder. I bought the bottles new and unopened this week. The dates looked good also. The TBLHG is rubbery and so is the Elmers Max, checked them again after 72 hrs. The Titebond red is much harder. The only thing I don't like about the TB original, and i'm sure you already know. Is it really shrinks and separates bad. Lots of voids in it, hence the drying down and getting hard I guess. I will watch that screw, going to kind of use it for a clamp as well. Someone asked why I liked Hot Hide but was using JB Weld Wood on the neck joint. The reason is, I don't trust myself with the HHG and the JB weld cures harder I assume? John has not had a chance to get back with me on that question I asked a few post back, about when to install the frets and fretboard. Would you comment on that? Thanks Gentleman!

  24. #44
    Henry Lawton hank's Avatar
    Join Date
    May 2009
    Location
    The Present Moment
    Posts
    1,927

    Default Re: The real glue strength

    Not seeing the cleaned up neck joint, perhaps your fix is ok. Everything I’ve read points to a stiffer neck is better with less energy loss overall. In my very limited experience as a hobbyist I’ve found the resonance and sustain of my boxes affected in both positive and negative ways by the amount of relief setup on my double truss rods. This effect may be because I prefer Loar neck profiles that are less stiff than the old clunky V necks. You know there’s movement because as you tune up you have to balance the effect one tuner has on the strings next to it. My Goldrush with a little more hefty maple neck still behaves this way but less so than my Black Walnut Loar profiled neck. I don’t know what’s going on to cause this but the effect is not subtle.
    Anyway I have found necks and neck joints are not static and inconsequential to what I love best in a good instrument, response, sustain and power. Most instruments I’ve played that were good instruments but less resonate and alive had stiffer necks that adjacent string tension had less affect on when tuning. Your experiences may not be the same but very precise wood to wood neck joints are needed for preventing the vibration absorbing effect of voids and soft glue.
    Is there any way to make a shim that matches the missing neck wood even if it is a multi piece wedge cake. Check out Japanese glueless construction joints for inspiration on methods if this might work in your case. A playable instrument should be easy to achieve and for many this is enough.
    "A sudden clash of thunder, the mind doors burst open, and lo, there sits old man Buddha-nature in all his homeliness."
    CHAO-PIEN

  25. #45

    Default Re: The real glue strength

    Quote Originally Posted by hank View Post
    Not seeing the cleaned up neck joint, perhaps your fix is ok. Everything Iíve read points to a stiffer neck is better with less energy loss overall. In my very limited experience as a hobbyist Iíve found the resonance and sustain of my boxes affected in both positive and negative ways by the amount of relief setup on my double truss rods. This effect may be because I prefer Loar neck profiles that are less stiff than the old clunky V necks. You know thereís movement because as you tune up you have to balance the effect one tuner has on the strings next to it. My Goldrush with a little more hefty maple neck still behaves this way but less so than my Black Walnut Loar profiled neck. I donít know whatís going on to cause this but the effect is not subtle.
    Anyway I have found necks and neck joints are not static and inconsequential to what I love best in a good instrument, response, sustain and power. Most instruments Iíve played that were good instruments but less resonate and alive had stiffer necks that adjacent string tension had less affect on when tuning. Your experiences may not be the same but very precise wood to wood neck joints are needed for preventing the vibration absorbing effect of voids and soft glue.
    Is there any way to make a shim that matches the missing neck wood even if it is a multi piece wedge cake. Check out Japanese glueless construction joints for inspiration on methods if this might work in your case. A playable instrument should be easy to achieve and for many this is enough.
    another look at the glues after a week......the TBLH and Elmers Max has dried much harder and acceptable, but the Titebond Red is still the hardest but shrinks really bad.

  26. #46
    Registered User j. condino's Avatar
    Join Date
    Nov 2005
    Location
    Asheville, NC
    Posts
    1,835

    Default Re: The real glue strength

    Quote Originally Posted by rcc56 View Post
    My sole objection to a well designed bolt-on neck is inserting or removing the bolt on an f-hole instrument.
    Not my idea of a good time.
    After 40 years building hundreds of new instruments and literally 1000s of repairs, heated granular traditional hot hide glue is my#1 choice. I'm able to glue an entire upright bass top in one session with zero problems; you don't need urea or brown bottled or fish glue, you just need to learn how to use the traditional glues properly. It is just a tiny little mandolin.....if your hot hide glue joints are not setting properly, neither are your bottled glue joints.

    For your bolt access issues: use a long handled allen wrench and go in through the endpin hole. Fast, easy, and used successfully for 1000s of instruments by several manufacturers. I did it hundreds of times at the factory.
    Spruce dork

  27. The following members say thank you to j. condino for this post:


  28. #47
    Registered User Inklings's Avatar
    Join Date
    Jun 2016
    Location
    North Shore of Masschusetts
    Posts
    119

    Default Re: The real glue strength

    Quote Originally Posted by grandcanyonminstrel View Post
    After 40 years building hundreds of new instruments and literally 1000s of repairs, heated granular traditional hot hide glue is my#1 choice. I'm able to glue an entire upright bass top in one session with zero problems;
    What's your workflow for that?
    Kirby Francis

    Francis Guitar Repair

  29. #48

    Default Re: The real glue strength

    Quote Originally Posted by justrythym View Post
    If glue has nothing to with sound transfer, then how could a good fitting joint with a bolt. Fender has been doing it for years, Taylor too maybe? There are some Mandolin Builders that build very nice sounding nice quality mandolins with bolt on necks. In my case it was insurance, because the joint is no longer dovetailed, it’s more of MT joint now.
    Sunburst's comment was in reference to the neck joint which has relatively little effect on tone. For that joint it's all about strength and reversibility. The area where vibration transference really is critical is in the sound box. Sloppy joints with PVA glue would tend to dampen the high frequencies, not as big of an issue with with guitars and mid-grade instruments. Tight fitting joints with little glue in them is the first priority. A glue that gets crystalline hard and doesn't creep under tension is ideal. Even the big companies will use "animal protein" glues for the premium models.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •