The answer to Gorilla glue ???

Discussion in 'Wood Construction' started by Tarkus, Jul 10, 2015.

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  1. Jul 10, 2015 #1

    Tarkus

    Tarkus

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    Ok, some times I have to admit to being an idiot, recently bought a FP-202 Koala (part 103) from a guy in FL close to finished. The craftsmanship looked good and I thought I asked all the right questions, so after driving it back to OR, I go about finishing up the tail feathers and cowling and fitting a few instruments, then it hits me that he mentioned Gorilla glue without going into details. After a few Emails it turns out he used it for most of the project, albiet well done, after I explained my concerns no more replies to my Emails ?
    So whats the best solution, a can of gas and a match ?
    Any ideas
     
  2. Jul 10, 2015 #2

    FritzW

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    Yeah, it's junk. Give me $50 and I'll haul it away for you:gig:

    I don't want to restart the age old polyurethane (Gorilla glue) vs. urea formaldehyde vs. polyvinyl acetate vs. epoxy debate. But IMHO any modern glue, properly used, will be stronger than the Pine your FP-202 is probably made out of and will probably last longer than you will. The trouble with Gorilla glue (polyurethane) is you can make a bad glue joint and it looks just like a good glue joint ...that goes for any kind of glue.

    There are too many variables involved to get a worthwhile "internet" answer. Get an old, grey haired, EAA Tech Counselor to look at it (make sure he knows what he's talking about) and go from there.
     
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  3. Jul 10, 2015 #3

    Norman

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    Polyurethane glue in a good tight joint is about 1/2 as strong as epoxy. Gorilla makes several different glues. If anything that flexes and your life depends on it is held together with foaming polyurethane Gorilla Glue I'd say a match might be your best option. Foaming PU can make a fairly strong joint (comparable to Titebond II) if the joint is tight and it was clamped well so that the foam can't push the surfaces apart. It fills gaps nicely but the foam isn't much stronger than styrofoam and it doesn't stand up to vibration well at all.
     
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  4. Jul 10, 2015 #4

    TFF

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    GG is an unknown. Holding wood is OK. Holding wood for years in on a thing putting up with vibrating, temperature changing, which does what to the glue and also expansion, possible other chemicals, big shocks like bad landings, just general exposure; I would be cautious.
     
  5. Jul 10, 2015 #5

    ekimneirbo

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    The biggest problem I have with Gorilla Glue is that it always goes bad (hardens) on the shelf after you use it once............
     
  6. Jul 10, 2015 #6

    Rockiedog2

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    There was a lot of credible GG info that came out on the old Yahoo Legal Eagle list some years back. I don't remember the details but there was some field experience or tests involved and the final word among the Eaglers including Leonard IIRC was don't use it. The info was very similar to what Norman said. The archives are still there if you wanta go and search it.
    Personally, I wouldn't fly it.
    I wonder if the seller/builder got educated after he built it thus the sale.

    I lost count of how many times I've been screwed/screwed myself.
     
  7. Jul 10, 2015 #7

    Workhorse

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  8. Jul 10, 2015 #8

    Rockiedog2

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    The GG vid was good. What he didn't show us is whether there was any wood torn when the joint broke. The foam he showed us was impressive. In the wrong way.
     
  9. Jul 10, 2015 #9

    Hot Wings

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    Put the top on tight and than store it upside down. Lasts a lot longer.
    Works great for stopping leaks in cracked concrete foundations .............

    While we are off topic a bit: use pipe dope on PVC glue and primer caps to keep them from going bad. It's far easier to open the next time too.
     
  10. Jul 11, 2015 #10

    Tarkus

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    Thanks Guy's.
    Expensive lesson :ermm: but a good reminder " If you want it done right, do it your self " Just found a local company that has a large inventory of very nice old growth fir lumber some of the best strait grain I've seen, w/16+ to the inch in 1X and 2X material 7% moisture, and they'll let me pick. :) any suggestions on a nice 103 biplane design?
     
  11. Jul 11, 2015 #11

    TJay

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    A good fix is get a fine cutting cooping saw and cut through every glue joint take the piece out and t-88 it back together, do it one piece at a time, sounds bad but it really doesn't take that long since everything is already pre fit. Might have 60hrs doing it big deal your building an airplane ha,its not a total loss. just more work than you thought.
     
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  12. Jul 11, 2015 #12

    JamesG

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    That's a good way to make lemonade out of that lemon. You might not even need to use the coping saw. A little big of prying will probably pop the joints apart.

    This is why I'd never buy someone else's homebuild, esp. and abandoned project. You never know what they did wrong or took shortcuts that could kill you. In this case, the OP was able to coax the seller to admit to using GG. If he had sworn up and down he'd used T-88, we'd probably be reading his (or someone's) obituary someday.
     
  13. Jul 11, 2015 #13

    Workhorse

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    That's a great fix for an apparently unsolvable problem. I'd like to add two hints. First japanese saws, I've done far more accurate cuts with these than with coping saws. A second could be making it airworthy and selling it to a drone/autopilot start up enterprise for trials. They use to be good on electronics but have little aircraft knowledge. They could have a good airframe to show their achievements at a fair price.
     
  14. Jul 11, 2015 #14

    ekimneirbo

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    One of these might help http://www.amazon.com/Xacto-X75300-P.../dp/B00004Z2U4

    You might try systematically cutting a few joints so that you end up with several sections of the airplane to work with. What I'm trying to say
    is tha rather than attempting to cut thru every joint, try ending up with sections that have no support other than the glue joint at one point....
    then try to flex it slowly and see if the glue gives way. If not, gingerly saw the glue a little and try flexing it again. As the glue joint is minimalized,
    the glue joints (if weak as suspected) may just give way without the need for precision sawing of each joint. Maybe.......
     
  15. Jul 11, 2015 #15

    JamesG

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    Except they will be just as annoyed if their aircraft comes apart in mid-flight and will still be alive to come looking for you. :nervous:
     
  16. Jul 12, 2015 #16

    TFF

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    Knock the whole thing apart and cut a 1/4" off each end of wood and re-glue with good stuff. Re kit.
     
  17. Jul 12, 2015 #17

    jany77

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    Roger Mann from ragwing aviation use polyurethane glue for his airplanes which is gg but under different name and brand ,I believe he used it in his production kits for storch replica and rw pitts replica biplane,it is shown on his build cd for rw19/20 stork
     
  18. Jul 13, 2015 #18

    Rockiedog2

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    If it was me and I was gonna try cutting the joints apart and regluing with T 88 or the like I would be particularly wary of the T88 not penetrating where the polyu had been. It may be ok if the joints are carefully scrapped before regluing. Or not. My concern would be that the GG penetrated the fibers to some extent and would block the T88 from doing same. if so then we still got what I would consider an unairworthy airframe. And the time involved IMO would possibly be prohibitive. That kinda stuff is usually much slower that expected in my experience. IMO it's still a wall ornament. I'd be thinking about those joints every time I flew it. I've done a lotta shortcut/makedo type stuff in the past and it just doesn't work for me. Ruins the all important peace of mind. Experience gained the hard way.
     
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  19. Jul 13, 2015 #19

    JamesG

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    That is why you flip the pieces over to use the other side. There's always a way. :)
     
  20. Jul 13, 2015 #20

    Topaz

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    Yeah, this would be my thinking as well, especially in high-stress areas. Cutting 1/4" off all the ends as was suggested above means that everything is now 0.5" short - doubtful the pieces will go back together this way.

    In the end, having the peace of mind that everything critical was done properly instead of an untested attempt to salvage a few hundred dollars of wood seems like a no-brainer to me. To the OP: Keep after the guy who built it wrong to give you some of your money back, and take it as a lesson learned. Build it yourself, and make sure it's done right. When your airplane is carrying your fragile body a mile or more up in the air, you'll thank yourself that you didn't take a chance.
     

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