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Thread: Are Your Glue Joints Repairable?

  1. #16
    Quote Originally Posted by larry merlau
    know i have a question for ya, how does the plastic resin glue do in reguards to the finishing aspect. does the joint line show up? clean up in reguards to the surface prep for stain or clear finish. are there some tricks that you have learned in the respect that you could share? thanks in advance, i had used that plastic resin in school but hadnt since maybe the teacher was on to somethng? i figured it was just because it worked with the heater they had to dry the joints.
    Sands better than any glue out there and light brown color provides an invisible glue line....it is noted for both. 30-minute open time.

    I don't know why it's not more popular with high-end hobbyists. What is the sense of doing traditional, repairable joinery if you stick it together with an unrepairable glue?

    PL Premium is a poly construction adhesive.
    Last edited by Bob Smalser; 06-30-2005 at 9:20 AM.
    “Perhaps then, you will say, ‘But where can one have a boat like that built today?’ And I will tell you that there are still some honest men who can sharpen a saw, plane, or adze...men (who) live and work in out of the way places, but that is lucky, for they can acquire materials for one third of city prices. Best, some of these gentlemen’s boatshops are in places where nothing but the occasional honk of a wild goose will distract them from their work.” -- L Francis Herreshoff

  2. #17
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    Quote Originally Posted by Bob Smalser
    Sands better than any glue out there and light brown color provides an invisible glue line....it is noted for both. 30-minute open time.

    I don't know why it's not more popular with high-end hobbyists. What is the sense of doing traditional, repairable joinery if you stick it together with an unrepairable glue?

    PL Premium is a poly construction adhesive.
    what about clamp time, overnight or can they be removed sooner?
    If in Doubt? Build it Stought!

  3. #18
    I'll have to look at the instructions.....but I almost always leave layups in the clamps over night.

    Urea-Formaldehyde and Resorcinol Glues - These glues are unequaled in all around performance. They have excellent water resistance, good gap-filling properties, sand extremely well, clean up with water and have the longest open time of most glues, approximately 20 to 30 minutes. They are creep-resistant and are used extensively in structural assemblies, veneering and production furniture shops. The downside is that they require longer clamping time - usually up to 12 hours. They also are sensitive to temperature and do not cure at temperatures below 70 degrees (65 degrees for Unibond, discussed below). They need to be carefully mixed in the proper ratio of resin to catalyst. The curing process releases small amounts of formaldehyde but this is a negligible amount. Some woodworkers may find the fumes irritating so it's a good idea to use these glues in well- ventilated areas and wear gloves when using. My favorite Urea-formaldehyde glue is Unibond 800 and I use it exclusively in my veneering work. This glue is sold as a modified Urea -formaldehyde and comes packaged as a liquid resin which is mixed with a powdered catalyst. The distinct advantage of this glue is that it contains no water, which is beneficial is veneering large and complicated assemblies. The powder comes in several colors, white, tan and brown so that the hard glue will match the wood being glued. Another manufacturer, Weldwood ,sells a UF glue called Weldwood Plastic Resin and the powder is mixed with water to activate it. This is an easy glue to use and is similar to glues used to bond plywood and structural beams. Don't use this glue for veneering - water makes the veneer curl. The glue can be colored by the addition of water-soluble dyes.

    Resorcinol formaldehyde glues like Weldwood, have exceptional water resistance and are used in marine applications. I don't usually use them on furniture, as the glue mixes to a dark, reddish glue line, but on hidden joints like mortise and tenons this would not be a problem.
    Last edited by Bob Smalser; 06-30-2005 at 10:15 AM.
    “Perhaps then, you will say, ‘But where can one have a boat like that built today?’ And I will tell you that there are still some honest men who can sharpen a saw, plane, or adze...men (who) live and work in out of the way places, but that is lucky, for they can acquire materials for one third of city prices. Best, some of these gentlemen’s boatshops are in places where nothing but the occasional honk of a wild goose will distract them from their work.” -- L Francis Herreshoff

  4. #19
    Wow, talk about my brain having info overload. Great information Bob. I have a couple of questions: What are your thoughts on traditional hide glue? Do you use UF on all of your interior work, every type of joint or PVA for your long grain to long grain joints? How does UF do with expansion and contraction ie: a small sliding dovetail? I have been taught that epoxy or PVA is the more flexible aternative. This thread is tremendously informational. Thanks for sharing your experience.

    Where did the above quote come from?
    Enjoy the journey,

    Martin


    ---------------
    Whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable --- if anything is excellent or praiseworthy --- think about such things. --- Paul of Tarsus

  5. #20
    Resin is more brittle than the others, but not as brittle as hide glue...and will make any interior joint you want to make with it to perfection. Also exterior joints if you keep them painted or varnished - many thousands of varnished, coopered spars have been made with plastic resin since the 1920's with few problems providing the layup was correct and the varnish coat maintained.


    Here's the data on resin:

    Pot Life - 4-5hrs@70 degrees/2.5-3.5@80/1-2@90.

    Open Time - 15min@70 degrees/10@80/5@90.

    Closed Time - 25min@70 degrees/15@80/8@90.

    Total Time to Assemble - 40min@70 degrees/25@80/13@90.

    Clamp Time - 14hrs@70 degrees/8@80/5@90.





    Looks like I got the thick Hotstuff brand cyanoacrylate glue to adhere to the aliphatic Titebonds.

    I'll do some more testing with it, but the problem is that cyano is so durn brittle that while it might repair a sliver or a layup, it is totally worthless to repair joints subject to seasonal movement or shock. One bump to that table leg and its reglued mortise and tenon joint will break again.
    “Perhaps then, you will say, ‘But where can one have a boat like that built today?’ And I will tell you that there are still some honest men who can sharpen a saw, plane, or adze...men (who) live and work in out of the way places, but that is lucky, for they can acquire materials for one third of city prices. Best, some of these gentlemen’s boatshops are in places where nothing but the occasional honk of a wild goose will distract them from their work.” -- L Francis Herreshoff

  6. #21
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    Quote Originally Posted by Bob Smalser
    Resin is more brittle than the others, but not as brittle as hide glue...and will make any interior joint you want to make with it to perfection. Also exterior joints if you keep them painted or varnished - many thousands of varnished, coopered spars have been made with plastic resin since the 1920's with few problems providing the layup was correct and the varnish coat maintained.

    I'll do some more testing with it, but the problem is that cyano is so durn brittle that while it might repair a sliver or a layup, it is totally worthless to repair joints subject to seasonal movement or shock. One bump to that table leg and its reglued mortise and tenon joint will break again.
    Bob, there appears to be (perhaps) some conflicting data here. You say that the plastic resin has done well and been around a long time. That in itself is "durn" good evidence to me but then you claim it is brittle but not much as hide glue. Certainly, hide glue has been around a long time, too, and seems to have done just fine. I guess the brittleness isn't a big deal, right? The CAs appear to be too brittle.

    Seems to me that aliphatic glues aren't brittle which could be why they move...they are flexible and are designed to move with the wood instead of resisting the wood movement. I guess this can be both good and bad and it may will depend on the wood species used, where it "lives", and its finish.

    I guess, in the end, the plastic resin and hides are time-tested and have done fine, correct? I think the market called out for slightly "eaiser" glues to use which might be why the aliphatic glues are prevalent. You gotta mix the resin (what a pain! ) and it needs >70 degrees F to cure properly (that can be painful in the winter in many areas of the US/Canada). Traditional Hide glue also needed a hot pot. Any comment on the current Hide glues in a bottle?

    I guess it is easy to see why aliphatics are popular...they are simply easier to use but perhaps we gave up something for ease of application??

    As always, thanks for your insight.
    Wood: a fickle medium....

    Did you know SMC is user supported? Please help.

  7. #22
    Quote Originally Posted by Chris Padilla
    I guess the brittleness isn't a big deal, right? The CAs appear to be too brittle.

    Seems to me that aliphatic glues aren't brittle which could be why they move...... Traditional Hide glue also needed a hot pot. Any comment on the current Hide glues in a bottle?

    I guess it is easy to see why aliphatics are popular...they are simply easier to use but perhaps we gave up something for ease of application??
    .
    Brittleness is a huge deal!

    That's why hide glues eventually break in round-tenon and crossgrain glue joints like M/T. That's also why resin glue fails outdoors....it's very water resistant, but when the finish deteriorates from neglect, the wood moves more...and that's what breaks a resin glue bond, not lack of water resistance.

    Liquid hide glues work, but not as well as the real thing hot outta the pot.

    Aliphatics are too flexible....that's why they creep and squeeze out of your glue joints months after the piece is done. Epoxy is the ideal for flexibility, followed by resorcinol.

    Aliphatics are certainly easy, but IMO are so massively popular because few know that they can't be repaired, something many old pros like me have known since the 1950's. And why do you spose that is, eh?

    You can use them if you like their convenience...but when your Granddaughter brings that treasured "heirloom" to somebody like me to fix in 60 years, she's in for some unpleasant truth. Why not fix those problems up front and save her that? Bet I don't lose any more shop time using resin than you do using aliphatics...it's all a matter of organization.
    “Perhaps then, you will say, ‘But where can one have a boat like that built today?’ And I will tell you that there are still some honest men who can sharpen a saw, plane, or adze...men (who) live and work in out of the way places, but that is lucky, for they can acquire materials for one third of city prices. Best, some of these gentlemen’s boatshops are in places where nothing but the occasional honk of a wild goose will distract them from their work.” -- L Francis Herreshoff

  8. #23
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    You definitely got me thinking here Bob. I've used the Titebond III, and Gorilla Glue almost exclusively. I think it's time I looked at the epoxies and plastic resins a little closer.
    I had shied away from epoxies because I was led to believe that a loose fit was required, or that epoxies didn't fare well with tight fitting joints. Is this an urban myth or legend?
    I had read about the brittleness of UF, but quite honestly never considered repairability. I'll be rethinking that decision also.
    Thanks for the post, as usual it was informative, and made me rethink the things I thought I knew about.

    PS. Don't get bummed out 'cause you think that people aren't paying attention or are "shouting over you". The type of posts that you make, and the information you give, are thought provoking, and will generate strong reactions, both positive and negative because they challenges someones personal belief, preconceptions or ideal.
    If you make a post and 20 people disagree strongly and respond. There are probably a 100 that read the post and learned something, but just didn't respond.
    Thanks for the Post again.
    Last edited by Mike Cutler; 06-30-2005 at 3:07 PM.

  9. #24
    I was led to believe that a loose fit was required, or that epoxies didn't fare well with tight fitting joints. Is this an urban myth or legend?
    Myth.

    Even your tightest, hammered-home joint has lots of room for unthickened epoxy.

    Just don't apply 500psi of clamping pressure to it.

    Go to West Marine and get their free book on epoxy use. Epoxy is best applied in stages....one thin coat left to soak in a while, then a slightly-thickened coat at assembly. I a super-tight application that will require more clamping pressure than I'm comfortable with because of poor fit, I use a heat gun to thin the first coat so it seeps real deep in the wood. Gentle heat thins epoxy to the consistency of thin cyano.
    “Perhaps then, you will say, ‘But where can one have a boat like that built today?’ And I will tell you that there are still some honest men who can sharpen a saw, plane, or adze...men (who) live and work in out of the way places, but that is lucky, for they can acquire materials for one third of city prices. Best, some of these gentlemen’s boatshops are in places where nothing but the occasional honk of a wild goose will distract them from their work.” -- L Francis Herreshoff

  10. #25
    Quote Originally Posted by Mike Cutler
    You definitely got me thinking here Bob.

    If you make a post and 20 people disagree strongly and respond. There are probably a 100 that read the post and learned something, but just didn't respond.
    Thanks for the Post again.
    Amen to that!
    More of us should maybe say something, but if you are like me and don't know a lot you tend to let those that know a bit more do the talking in this kind of dialog.
    One thing that you can bet on though... any time Bob Smalser posts a how-to it goes in my notebook!
    Thanks Bob... teach away.

  11. #26
    It's very sad that marketing can mute out experience. That's where places like this can have their effect.

    The problem with glue, is that this issue won't be showing it's ugly head for many years. By that time people have habits and preferences ingrained.

  12. #27
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    Quote Originally Posted by Ken Kimbrell
    Amen to that!
    More of us should maybe say something, but if you are like me and don't know a lot you tend to let those that know a bit more do the talking in this kind of dialog.
    You'd think that would stop yours truly but not so....
    Wood: a fickle medium....

    Did you know SMC is user supported? Please help.

  13. #28
    Cyanoacrylates are the only glues that stick to Titebond residue (but are so brittle themselves that they are useless for most structural applications in wood):



    Epoxy sticks to 3M 5200 marine sealant:



    Epoxy also sticks to PL Premium poly construction adhesive:



    5200 sticks to 5200:



    And PL sticks to PL:



    But after only one week of soaking in 60-degree pond water, the 5200 is already begining to lose its adherence...just like I've said:



    But the PL Premium glueline to the immediate right of the 5200 in the pic is behaving much more like the liquid poly to its right than it is like the 5200. I no longer think it's gonna lose adherence like the 5200 does.

    We'll see by the end of the season submerged.
    “Perhaps then, you will say, ‘But where can one have a boat like that built today?’ And I will tell you that there are still some honest men who can sharpen a saw, plane, or adze...men (who) live and work in out of the way places, but that is lucky, for they can acquire materials for one third of city prices. Best, some of these gentlemen’s boatshops are in places where nothing but the occasional honk of a wild goose will distract them from their work.” -- L Francis Herreshoff

  14. #29
    As usual......good stuff Bob. I still think a book is in your future.

    Question: Do you think that different species would give differing results? I know you used d. fir. What about spruce? Hardwoods such as walnut or alder or maple?

    As for scientific validity, a well-thought-out experimental design from a life-long woodworker is much more impressive than a poorly designed experiment from a clueless knucklehead with a few M.S.'s or ph.D's attached to their name.

    Arnie Grammon, M.S.

    (What did I just call myself? )

  15. #30
    Species wil have no effect. The glue either sticks to the other glue residue, or it doesn't.
    “Perhaps then, you will say, ‘But where can one have a boat like that built today?’ And I will tell you that there are still some honest men who can sharpen a saw, plane, or adze...men (who) live and work in out of the way places, but that is lucky, for they can acquire materials for one third of city prices. Best, some of these gentlemen’s boatshops are in places where nothing but the occasional honk of a wild goose will distract them from their work.” -- L Francis Herreshoff

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