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Thread: glue 1 surface or 2

  1. #31
    I tend to do both surfaces because better safe than sorry. Also, by doing both surfaces I can apply thinner amounts and I find it’s less messy in terms of application.

    I mostly use hot hide glue. If I need more time for a complicated glue-up then I just add salt which works phenomenally well and takes all the (brain) stress out. As a woodworking when I have a spare moment kind of guy I cook up my glue in a large batch and then pour it into silicone ice cube trays and freeze it. Then I pop those into a container and store the cubes in the freezer. When I know I will glue something up I just have to grab the appropriate amount and put them in the pot (glass spice jar in a baby bottle warmer) 15 minutes before I need the glue. Whatever glue is left over stays in the jar and goes in the fridge. If I don’t know that I’ll need glue in the next couple weeks then I just pour it into an ice cube tray and re-freeze it and put it back with the others in the freezer. I used to keep a bottle of LHG around for convenience, but when my last bottle got old I just didn’t buy it anymore as I just was rarely using it. The ice cube thing has been convenient enough for me.

    I think they didn’t figure out that you could extend the open time of hide glue with urea or salt until the middle of the 19th century. Before that if you had more glue to apply than was humanly possible in the short amount of time available you had to heat up the wood parts and/or the entire shop. To me that sounds like a gigantic pain the butt (and expensive trying to heat the whole place up).

  2. #32
    Quote Originally Posted by Richard Hutchings View Post
    Warren, I think you are far beyond a hobbyist. Woodworking day in and day out to make that many glue joints certainly allows for having a glue pot at the ready. I spend 1/2 hour to an hour in my shop and then I'm off to my job or whatever. I think even in retirement I won't be spending that much time Woodworking. Maybe I'll jump to a couple of hour here and there throughout the day so it still won't make a lot of sense for me. At least that's my thoughts right now, not having a crystal ball. Don't get me wrong I do enjoy using it when I have more time but that's rare these days. Give me some Titebond.
    I was responding to this quote in the previous post:

    For any glue up of size, it's very difficult to keep the glue liquid long enough to get the parts together. I can't imagine how our ancestors glued up dovetails with hot hide glue. They must have put a lot of urea into the glue. Or maybe the dovetails were mechanically strong enough that t didn't matter about the glue.

    Or maybe they had more experience using hide glue.

    Additives in hide glue to slow down evaporation also make it make it vulnerable to gain moisture and get gummy when the humidity is high, making for weak joinery. Yellow glue and white glue make the joint much more difficult to disassemble for repair. Nobody wants to restore stuff like that, so more likely to be thrown away.

    As Andrew Hughes said yesterday:

    If my work were to survive long enough for a restoration someone's not going to be happy.

  3. #33
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    Quote Originally Posted by Warren Mickley View Post
    I was responding to this quote in the previous post:

    For any glue up of size, it's very difficult to keep the glue liquid long enough to get the parts together. I can't imagine how our ancestors glued up dovetails with hot hide glue. They must have put a lot of urea into the glue. Or maybe the dovetails were mechanically strong enough that t didn't matter about the glue.

    Or maybe they had more experience using hide glue.

    Additives in hide glue to slow down evaporation also make it make it vulnerable to gain moisture and get gummy when the humidity is high, making for weak joinery. Yellow glue and white glue make the joint much more difficult to disassemble for repair. Nobody wants to restore stuff like that, so more likely to be thrown away.

    As Andrew Hughes said yesterday:

    If my work were to survive long enough for a restoration someone's not going to be happy.

    I've always wanted to learn to use hot hide glue and intend to give it a try at some point. I like liquid hide glue and tend to use it, but I'd like to try the "real stuff" at some point, both to find out if there's any advantage, and as a learning experience.

    What's your advice on how to use it well and how do you address common problems such as gluing up large / complex pieces?

  4. #34
    Join Date
    Dec 2006
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    Of course the thread transformed into a HHG thread. That's fine with me, maybe I'll learn something and want to fire up the pot again. I already know in my heart that HHG is the best woodworking glue on the planet, no denying. I haven't tried the Frank Ford ice cube tray thing yet and maybe I should. I think this is where Chris may have got the idea, I could be wrong but Frank did a lot of testing on HHG and had some great ideas.

    He tested it's resistance to heat and found that a fully cured HHG joint was just about impossible to separate using heat alone. Steam is really the only way to separate them and it works really well for guitar dovetails.

    Those cubes of HHG can be microwaved for quick use, I never tried it but again I should because I really love the properties of HHG.

    I have in the past removed backs from a guitar and mandolin and reglued them with HHG using technique where the glue is applied to both surfaces and you take as much time as you want, let it cure a little. Set the back on the instrument and clamp it up and just go around the seam with a heat gun, violin makers used an oil lamp, and the fresh glue would start melting and the joint would close up solid.

    I think I'm talking myself back into HHG, damn!

  5. #35
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    Have never used any form of Hide Glue....and I doubt IF I ever will.....kind of set in me ways...I guess.

    Thursday Morning, 2nd glue up.JPG
    Coated the tenons completely, thin coat... no glue IN the mortises, no room....almost no squeeze out. Bottle of glue has the face of a Gorilla on it....

    My shop, my rules?
    A Planer? I'm the Planer, and this is what I use

  6. #36
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    And there's no reason to start. Keep on doing what you do.

  7. #37
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    Quote Originally Posted by Richard Hutchings View Post
    And there's no reason to start. Keep on doing what you do.
    As the saying goes, "you can't teach an old dog a new trick," unless the old dog wants to learn a new trick.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  8. #38
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    Quote Originally Posted by steven c newman View Post
    Have never used any form of Hide Glue....and I doubt IF I ever will.....kind of set in me ways...I guess.

    I was convinced by an expert and a book of the importance of using hot hide glue for one project: rebuilding a player piano. Rebuilding requires disassembling many parts, wood-to-wood, wood-to-bellows cloth. Some parts can be taken apart cleanly by applying heat with an old clothes iron. The idea of sticking with hide glue is to be kind to the guy who rebuilds it the next time, maybe 50 years later.

    I haven’t used it for anything else.

    JKJ

  9. #39
    Join Date
    Jun 2008
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    So Cal
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    In my area I idea of heirloom furniture isn’t something people think about.
    I see society more into temporary furnishings.
    Ive made a couple pieces that can be easily taken apart and put back together. Wedged tenons and doweled joints.
    I like using old brown glue for small boxes but it mostly for my own personal reasons.
    Good Luck everyone
    Aj

  10. #40
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    Dec 2016
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    The only way you can have one rule, is to coat both surfaces.

    Getting past that, if your face joint touches over say 60% of a large area it will be very strong so the coating is a non issue if done in a timely fashion. Adding glue to the other surface will not increase contact area.

    If your glue up is delayed and the one surface with glue dries too much it may well not transfer to the other surface well and give a ‘dry joint’. Woods with high absorption will speed drying and if there is high absorption then thinly coating both surfaces with partial drying ensures a better joint with far less squeeze out; such as edge glueing white cedar.

    Joints with modest area, subject to mechanical stress, such as mortice and tenon should be well designed and made with appropriate shoulders and pegged inside such that no glue is required. Then the addition of glue to the tenon and back of the mortice is just a nicety.

    Dovetail joints in drawers, carcasses etc have a large surface area and are usually very sound mechanically when assembled, so modest glue on one surface lessens clean up and finish application issues in a highly visible joint.

    The worst case relying on glue is edge jointing boards. The contact area of the joint is key. Does thin application to both surfaces generate less squeeze out? Does one sided application provide enough glue? Yes there will be enough glue, will there be enough contact area?
    ​You can do a lot with very little! You can do a little more with a lot!

  11. #41
    I would suggest a test, which I have done. Put glue on one surface, then clamp the boards together. Do a good clamp, just the same as you would do normally. Then take the boards apart and see if there is glue on the surface that was dry.

    In my tests, the "dry" surface was fully coated. Clamping causes the glue to be spread well over the surface. Of course, you can't starve the first side with glue - just apply the normal amount of glue.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  12. #42
    Quote Originally Posted by William Fretwell View Post
    Joints with modest area, subject to mechanical stress, such as mortice and tenon should be well designed and made with appropriate shoulders and pegged inside such that no glue is required. Then the addition of glue to the tenon and back of the mortice is just a nicety.
    There are many designs using mortise and tenon and spline joints that don't lend themselves to pegging and do require a thoroughly glued surface for optimum strength. Do an experiment: Put together a well-fitted mortise and tenon, a Domino joint and a biscuit joint with glue on only one side of the joint, take them apart and check out the glue coverage on the unglued side, then decide how to proceed.

  13. #43
    Join Date
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    Both sides for many reasons which are just my reasons and beliefs.....no scientific data attempted or suggested here, like someone said above here my shop my way.

    Glue penetrates into wood coating one side provides more glue penetration there and none in the mating piece until joined together.

    Depending on elapsed time and climate considerations PVA glue tens to skin over rather quickly. This may reduce the transfer of glue to the dry side joint and lessen the glue penetration.

    PVA before cure will always bond to PVA totally

    End grain joints are prone to absorbing glue quite rapidly reducing the surface coating available for bonding and then sharing the available coating with the dry side joint can lead to a glue weak , glue scarce joint.

    It is more beneficial to manage the amount and method of adding glue to a joint. A reasonable full coverage to both sides insures the entire joint has access to the stuff that will keep the joint together for years. Why take the chance, slim as it may be that there may be a relative dry or weak glue transfer with a wet to dry joint.

    A gallon of glue is or was 4 times more expensive than gas for your car but a gallon of glue will take you way farther than a gallon of gas in your car why sweat the economics.
    mike calabrese

  14. #44
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    I have a 90 degree joint in 3/8” Baltic Birch plywood with one #10 biscuit (the smallest). I offer it to clients to see if they can pull it apart, they can not.
    ​You can do a lot with very little! You can do a little more with a lot!

  15. #45
    Join Date
    Apr 2018
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    Cambridge Vermont
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    I glue both sides as I like to work the PVA into the wood. The exception is if I can move both pieces around some to help spread the glue. If something works why change. I just don't want a glue joint to fail down the road when it'll be hard to fix just because I wanted to save a little time and glue.

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