Polyurethane Glue Tips?

Discussion in 'Archived Threads 2001-2004' started by Vince Bray, Oct 17, 2001.

  1. Vince Bray

    Vince Bray Stunt Coordinator

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    How do you control the expanding glop when you're glueing the finish surface of a cabinet? Do you just apply the glue very carefully and try to not get it on the finish, or sand it off, use a solvent such as min. spirits? What works here? With yellow glue, you have to be careful since the glue won't take stain. Is that the case with the poly?
    Thanks for your help!
    Vince
     
  2. Pete Mazz

    Pete Mazz Supporting Actor

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    Polyurethane glue's biggest advantage and biggest disadvantage is it's ability to expand. It's very hard to control the amount applied and the resulting "foam" expands for quite a while. Naptha is the safest to clean it up with, but mineral spirits will work, as well. I would be very hesitant to use it on pre-finished panels. If you have good straight cuts, I would recommend yellow wood glue. It's more than strong enough for speaker enclosures. The MDF will fail before the glue bond will. Even if your cuts are less than perfect, I would still use yellow glue and then just caulk the inside joints.
    Pete
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  3. Vince Bray

    Vince Bray Stunt Coordinator

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    What I will have is veneered plywood, not yet finished, and oak hardwood corners. I will finish the panels after assembly. With yellow glue, there is the issue of glue keeping stain from adhering around the joints. I like the poly glue, I just wonder how it affects later finishing around the joints if not controlled carefully when glueing.
    Thanks again,
    Vince
     
  4. Jack Gilvey

    Jack Gilvey Producer

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  5. Vince Bray

    Vince Bray Stunt Coordinator

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    That's what I was afraid of... I also discovered that they aren't kidding about the clamping deal. If you don't clamp it very well, the glue foams in the joint and it is not at all strong. I am at the stage of adding the second layer to my 15.2 cube, and since I'm this far I think I'll stick to poly glue, but I'm going for some gorilla glue instead of the pro-bond I've been using.
    I guess I'll try masking it and make a test joint with masking tape to see what happens. This is way to much effort to have streaks in the finish from glue.
    Thanks,
    Vince
     
  6. Jack Gilvey

    Jack Gilvey Producer

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    I used Gorilla glue on this box. Lots of clamps are required for the most contact, although that's the way it is with yellow glue,too. You can see all the runoff. It was the first time I'd used the glue, and maybe I used too much, it did fill any and all gaps, though, no caulk needed. Do watch out for the clamps, though, they might become a permanent part of your project as the glue starts oozing. [​IMG] I like to learn everying the hard way.
    [​IMG]
    Let me know how it works with the tape.
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    [Edited last by Jack Gilvey on October 17, 2001 at 08:45 PM]
     
  7. Vince Bray

    Vince Bray Stunt Coordinator

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    I'll try it and report back. The other issue I have is laminating the second layer to the first and getting even pressure all the way across the surface. I'm planning to make some ply strips about 2" wide that are planed thinner by about 1/16 at the ends. That way when clamped down across the surface, they'll press the center first, and finally the edge. Boy, this got complicated... masking tape galore and all the clamps [​IMG]
    Vince
     
  8. Vince Bray

    Vince Bray Stunt Coordinator

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    Oh, yeah, I have chunks of plywood stuck to the clamps too [​IMG]
     
  9. Pete Mazz

    Pete Mazz Supporting Actor

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    Small amounts of wood glue squeeze out can be cleaned up completely with a wet rag and clean water. It's very easy to control the amount of glue being applied. I've rarely had problems with staining and finishing when done this way.
    Pete
     
  10. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    My best tip for polyurethane glue is "Do not use it". Why do you think you should use it? It is good for applications where there are small gaps/uneven surfaces and should be well-clamped in those instances. The best wood joints start with accurately sawed wood (use a quality blade). With smooth straight cuts, you'll have joints that fit and all you then need use is the good old yellow carpenters glues. They are as strong as poly, cost a lot less and are easy to clean up.
     
  11. James Mudler

    James Mudler Stunt Coordinator

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    I'll add one thing. Wear gloves. That stuff is a nightmare to get off of your hands. My wedding photos have signs of the good ole gorilla glue.
    Jack, I too learn the hard way [​IMG]
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    Luke, I'm your father
     
  12. Vince Bray

    Vince Bray Stunt Coordinator

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    I've been using the disposable gloves too. The poly is amazing in that it will stay on a fingernail for 2+ weeks. Clearly it is long-lasting.
    I found today that very thin layers of glue seem to be the ticket. A tight fitting joint and a thin spread of glue still gives good adhesion across the surface when laminating. I'll know tomorrow when I attempt to pull apart the pieces I glued tonight.
    Thanks for all the suggestions!
    Vince
     

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