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Hide glue question

  • 1.  Hide glue question

    Registered Piano Technician
    Posted 02-19-2019 22:34
    What's the difference between hot hide glue and liquid hide glue? Do they function differently. Is one better than the other for the same job in which hide glue might be called for? If yes, why?

    Thanks --

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    Geoff Sykes, RPT
    Los Angeles CA
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  • 2.  RE: Hide glue question

    Posted 02-20-2019 06:37
    While I do not have an expert opinion to offer, I can offer my opinion based on practical experience. My belief is that ultimately both produce a joint of similar strength and final characteristics. The difference appears to be in the application. Liquid hide glue is simply easier to apply in that you don't have to heat it. It also has a much longer open time during application. Hot hide glue has to be heated, but it offers the advantage of having an extremely high initial tack. The high initial tack offers the advantages of holding a piece in place without clamping as well as preventing the glue from migrating into a porous piece - as in when gluing felt.

    The other HUGE advantage of hot hide glue is that wonderfully goopy and fun to mix up and use!

    Is that what you were looking for?

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    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
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  • 3.  RE: Hide glue question

    Posted 02-20-2019 07:53
    Hot hide glue has superior holding properties which is why it is used for veneer work and player work. Cold hide glue never really hardens well and is not a glue where strength is involved.
    I'm sure John Tuttle has more info on his website: http://www.player-care.com
    https://www.player-care.com/hide_q-a.html

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    Regards,

    Jon Page
    mailto:jonpage@pianocapecod.com
    http://www.pianocapecod.com
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  • 4.  RE: Hide glue question

    Member
    Posted 02-20-2019 10:21
    I believe the cold hide glue uses,,or used to use urea to keep it liquid and it has a shelf life. There are dates on the bottles
    Plus with hot glue you have the double viscosity. You can thin hot glue with water or heat. Various formulas are available. Kawai has their own proprietary formula for hanging hammers. You want a hard glue but not to the brittle extent for that. Some glues transmit sound better. Use a softer hide glue on felts. It doesn't soak in as much and has some play time.





  • 5.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-20-2019 10:23
    Urea content, I'm pretty sure.  The question is does high urea content achieve the same degree of hardness.  I don't know the answer.  Liquid hide glue I use all the time in wood to felt applications, like bushings,  I don't think I would use it to glue in a soundboard.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 6.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-20-2019 10:40
    I did some shop experiments with various glues, including liquid hide glue. Compared to Elmers and Titebond, it seemed to take forever to set, and once set did not seem to hold as well, especially for felt. I've since given up the idea that liquid hide glue has any useful place in piano work. I've become a big fan of Titebond Quick and Thick. On a recent thread about Yamaha butt flange cords, someone mentioned using liquid hide glue, which seems like a rather odd choice due to it's long drying time.

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    Scott Cole, RPT
    rvpianotuner.com
    Talent, OR
    (541-601-9033
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  • 7.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-21-2019 13:00
    The biggest advantage with hide glue is reversibility without damage to the wood.  In the case of bushings they remove easily with no wood coming with them.  I've had no trouble with liguid hide glue holding in such applications and that's after decades of use.  I wouldn't use Titebond trim glue with bushings, though I do use it for hammer hanging.  Liquid hide glue does have an expiration date after which it may not harden properly.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 8.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-21-2019 13:26
    I've used liquid (cold) hide glue, tried hot hide glue, and mostly stick with one of the Titebonds. (Varying depending on the job.) I agree with Scott here, cold hide glue takes forever to set. It's usable, but in my opinion Titebond works much faster and yields just as strong a joint as cold hide glue. I really can't think of a situation where I'd opt for cold hide glue over Titebond. 

    That said, I carry cold hide glue in my repair kit, along with Titebond. Why? Probably because I already brought it and it fits perfectly in its spot.

    Edit: I’m mostly a field technician and do very little shop work, so that affects my decision about which glues I use regularly. If I did mostly shop work my opinion may be different. But I’m not, so it isn’t. 

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    Benjamin Sanchez
    Professional Piano Services
    (805)315-8050
    www.professional-piano-services.com
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  • 9.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-20-2019 11:09
    Hi Geoff,

    liquid hide has urea added to it to slow down the gel time.   I believe commercial  versions also add preservatives  to prevent spoilage.

    There is a shelf life on liquid hide.
    It does not produce as strong a bond.
    It is not a good choice for bushing cloth as the long gel time will allow it to penetrate deeper and perhaps through the cloth.

    Use it when you need time to align parts BUT need an actual glue, not an adhesive like PVA.

    You can purchase urea at the local hardware store.  Also known as fertilizer.  10-0-0


    Plenty of info online to use for proportions if you decide to make your own.

    Dale Fox RPT






  • 10.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-21-2019 23:23
    > Use it when you need time to align parts BUT need an actual glue, not an adhesive like PVA.

    OK, then, next question: What's the difference between an actual glue and an adhesive? Isn't PVA the same as white glue?

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    Geoff Sykes, RPT
    Los Angeles CA
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  • 11.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-22-2019 02:35
    Although the terms glue and adhesive are often used interchangeably I make definite distinctions.

    PVA and other similar adhesives, Tite Bond, White  glue, much of what is used in industrial applications that comes on 50 gallon drums,  etc, I think of as flexible bonding agents.
    Depending on the additives to the basic PVA  chemistry they exhibit differing hardness, water resistance, heat resistance, etc. For example, Tite  Bond comes in at least three separate formulas with different hardness, creep under load characteristics, open time and water resistance. This makes one type perhaps more suitable for specific piano related use than others.

    Hide glue, which is a true glue, is rigid when set.  Additives in the cold (liquid)versions might give you more open time at the trade off of less hardness and slightly lower strength.

    Urea formaldehyde, is a synthetic resin made of a combination of urea and formaldehyde.
    I think of it as a glue not an adhesive as it is brittle and inflexible like hide glue when cured.
    It has the disadvantage of being non-clear (dark red in fact) and requiring a minimum wood moisture content of 8% to insure it doesn't form a starved glue joint.  It is an innapropriate glue for those who make compression crowned sound boards as the EMC of the wood is too low.

    Both PVA based adhesives and true glue require appropriate clamping pressure in order to produce a quality bond.  Both require good mating of wood surfaces to prevent an excessive thickness of glue in the joint being bonded. I have often noticed thick glue lines in the spaces between go-bars on old removed sound boards where the ribs are easily dislodged with a sharp blow.  This is one reason I prefer the use of Pnuematics when gluing ribs onto new panels.  ( Not to mention the massive structure  needed for a go-bar deck.)

    Then there is the world of epoxy resins, an adhesive which can do so many tasks, requires the use of low clamping pressure,  can bond items with poor mating, be modified for stiffness, sandabilty, open time, etc. Sorry for the run on sentences.

    Of course, there are a myriad of other adhesives that we use daily. Contact cements, PVC-E, hot glue guns, etc.

    Use them all, just know there characteristics.

    Dale Fox RPT









  • 12.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-20-2019 11:50
    Great, and helpful information from everyone. Thanks!

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    Geoff Sykes, RPT
    Los Angeles CA
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  • 13.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-21-2019 19:03
    So the sum of the matter is:

    1) If you NEED very long open working time AND
    2) You use very fresh (as fresh as you can buy) cold hide AND
    3) If absolute maximum strength is not a number one priority...
    Then CHG can have a place in your cabinet or tool bag.

    Otherwise, HHG is your friend once you learn the ropes.

    Pwg

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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  • 14.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-21-2019 19:58
    Peter,

    I think that's a good summation.  Cold hide does have a few advantages for player pouches and valve leather.

    Occasionally I do some actual wood glue up with it.  Even though it's slightly weaker a joint than hot hide, the wood fibers will give up way before the glue joint will.  And it's an actual glue, not an adhesive like PVA based stuff.

    I usually make my own, so I can tailor it's gel time for something a bit less than the pre-made variety.

    Dale Fox RPT






  • 15.  RE: Hide glue question

    Member
    Posted 02-21-2019 22:51
    As mentioned, I too carry some cold hide glue. Why?
    Compatibility. If the joint or felt that came apart was hide glue, a small amount re energizes the glue that's there. 
    Taking things apart later,,,, sometimes I consider that but usually the next step is replacement of parts.
    Here in the mountains or the desert, It sets plenty fast enough. 





  • 16.  RE: Hide glue question

    Registered Piano Technician
    Posted 02-22-2019 06:18
    Jumping in here a little late.  
    There was an article in Fine Woodworking magazine several years ago that tested and compared wood glues and adhesives including cold and hot hide glues.  The results were that (fresh) cold hide glue actually produced a stronger bond than hot hide glue.  However, cold hide glue was found to be very susceptible to high humidity and would fail if the humidity was too high.  The performance of the glue would also deteriorate quickly once past its expiration date.  
    Regarding definitions of glue vs adhesive:
    A true glue is organic (hide glue, fish glue, casein glue, etc.) and an adhesive is synthetic ( PVAs, epoxy, plastic resin, etc.)

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    William McKaig
    Tampa FL
    813-831-4179
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  • 17.  RE: Hide glue question

    Posted 02-22-2019 08:34
    Read the link in my post above. Your questions will be answered.

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    Regards,

    Jon Page
    mailto:jonpage@pianocapecod.com
    http://www.pianocapecod.com
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  • 18.  RE: Hide glue question

    Registered Piano Technician
    Posted 03-07-2019 22:24
    There are several forms of "cold" hide glue. Rather than try to explain the differences here, I suggest you go to the internet. One source of useful information can be found here:  https://www.popularwoodworking.com/article/hide-glue-in-liquid-form/

    ddf

    --
    Delwin D Fandrich
    Fandrich Piano Company, Inc.
    Piano Design and Manufacturing Consulting Services -- Worldwide
    6939 Foothill Ct SW -- Olympia, WA 98512 -- USA
    Phone 360.515.0119 -- Mobile 360.388.6525





  • 19.  RE: Hide glue question

    Registered Piano Technician
    Posted 03-07-2019 22:36
    I have used the do it yourself cold hide glue recipe found in the article Mr. Fandrich linked to for about a year now. I like it better than Titebond cold hide glue and it has the added benefit of forcing me to use my glue pot and get used to making hot hide glue.

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    Karl Roeder
    Pompano Beach FL
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  • 20.  RE: Hide glue question

    Registered Piano Technician
    Posted 03-07-2019 22:41
    This is a great article. Explains a lot. Thanks for sharing.

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    Geoff Sykes, RPT
    Los Angeles CA
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  • 21.  RE: Hide glue question

    Posted 03-08-2019 18:02
      |   view attached
    Everything you ever wanted to know about hide glue, including recipes for waterproof hide glue, gluing to metal etc etc:

    http://www.pianofortesupply.com/books/hide-glue/glue-book-2/


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    Jurgen Goering
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