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Thread: Cold creep in modified PVA glues?

  1. #1
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    Cold creep in modified PVA glues?

    Ordinary wood glue, for instance Titebond original, is infamous for cold creep. Does anybody know if the modified PVAs like Titebond II or Titebond III creep less?

  2. #2
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    That's a good question. I suspect the TB II would creep a little less than original, because it seems to cure a little harder. I don't think I'd use it on any crazy bent laminations though.

  3. #3
    I've used it and not seen creep. But mainly I use the powder Weldwood stuff. I still say creep is an old white glue thing.
    You could ask the Titebond reps, they always answer fast.

  4. #4
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    I've experienced "creep" with TB-III for sure...
    --

    The most expensive tool is the one you buy "cheaply" and often...

  5. #5
    Yeah, nobody likes Titebond 111

  6. #6
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    Any thermoplastic glue will creep if the temperature and stress is high enough to exceed the shear strength. I know lots of folks say they use PVA type glues w/o issue. I'm sure it's true as long as the temp. and stress levels are low enough. But like Jim, I have seen creep with TB type glues (had to be Original or TB II because III hadn't been invented yet) in simple flat laminated table legs. Every year I can feel the joints as the two 6/4 pieces of stock move with the seasonal changes in RH. I sure wouldn't use TB III for an exterior door that will get any exposure to direct sun.

    John

  7. #7
    They all creep for me and with regards to sun/heat just leave any one of them in a car in the sun (even if they are not in the direct sun) for an hour or two and you'll see immediate glueline failure. It gets worse the higher up the "ultimate" chart you get. TBIII will fail in a vehicle in an hour or less. That's a pretty extreme test for their ultimate value.

  8. #8
    Last edited by Mike King; 09-10-2019 at 4:55 PM.

  9. #9
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    Quote Originally Posted by Mike King View Post
    [url]...If glue creep is really an issue, it would seem Unbind 800 is your best bet...
    Unibond 800 is a urea-formaldehyde glue. I used to use it for bent lamination, but stopped. I was concerned about formaldehyde exposure. Formaldehyde is a known carcinogen, and the whole building industry is moving away from it. Now I use epoxy when I need a no-creep glue, and when I'm willing to use a two-component glue. I keep hoping to find a one-component low-creep glue, hence the original post in this thread.

  10. #10
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    Unibond 800 works great, especially in a vacuum bag where the pressures are low. Weldwood Plastic Resin Glue works well, too, but according to the instructions requires much higher pressures, higher than what you can get in a vacuum bag. I used to use mostly PRG because it was easy to obtain but I'm switching back to Unibond 800 after having a couple of bond failures with shop sawn veneer. But both products have essentially zero creep and I have used them for many bent laminations w/o problems.

    As far as the formaldehyde in both products, everyone has to decide for them self what risk they are willing to take. Gasoline has benzene, another known carcinogen, and most of us fill up the tank on our car, lawnmower, etc. w/o even thinking about it.

    John

  11. #11
    Quote Originally Posted by Jamie Buxton View Post
    Unibond 800 is a urea-formaldehyde glue. I used to use it for bent lamination, but stopped. I was concerned about formaldehyde exposure. Formaldehyde is a known carcinogen, and the whole building industry is moving away from it. Now I use epoxy when I need a no-creep glue, and when I'm willing to use a two-component glue. I keep hoping to find a one-component low-creep glue, hence the original post in this thread.
    Seems the only one part option with no Formaldahyde (reasonably speaking) is PU which sucks for the mess. Im running epoxy as well as opposed to UF but I dont know which is worse for mess, epoxy or PU. If you can get pretty accurate with PU the mess can be minimized but without a doubt if you wanting to ensure full coverage there is no way around it. Epoxy is really no better in that regard so I have been holding epoxy back for the most extreme situations.
    Sometimes I just want to look at pretty pictures,... Thats when I go to the Turners Forum

  12. #12
    Thanks John,good detail. I've used a lot of the plastic resin stuff for glueing up large ellipses. In those cases the only
    "clamps" are the lumber banders. Bands are no closer together than 8 to 10 inches. And in the middle flatter areas I can actually pick up the plies an inch or more off the form. I've always put glue on both sides,
    I ve seen some try "heavy coat " to just one side . That did not work. Never used Unibond but always heard its "the real
    stuff".

  13. #13
    Cold creep can be caused by different reasons. On water soluble glues humidity can make the glue swell up in damp weather. It can also be caused by wood movement if the wood shrinks leaving the glue line so an exterior glue won't be exempt from the phenomenon.

  14. #14
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    What the heck is cold creep? Is my furniture going to fall apart?
    I use Titebond II and III...
    “Pay no attention to what you cannot control..” Epictetus, 100 A.D.
    It costs nothing to be kind to others

  15. #15
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    Quote Originally Posted by Mark Daily View Post
    What the heck is cold creep? Is my furniture going to fall apart?
    I use Titebond II and III...
    Cold creep is shear (displacement) of the glued surfaces at room temperature, and happens when the shear stress exceeds the creep strength of the glue. It's often seen with joints that go out of alignment with changes in seasonal expansion/contraction of pieces that are glued together, like in a tabletop, or parts made up from laminated pieces. Another case is in bent laminations that try to straighten out with time.

    Your furniture is not likely to fall apart, but if it does it will do so slowly if cold creep is the problem. But don't take anything you made with TB glues in bent laminations out in the hot sun as Mark pointed out.

    And for those using epoxy in exterior projects, as I often do, recognize that many of them including West Systems loose substantial strength at elevated temperature, similar to PVA glues.

    John

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