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5 minute epoxy strong enough?
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=31621		 Page 1 of 1
Author:  crich [ Sat Mar 26, 2011 3:13 pm ]
Post subject:  5 minute epoxy strong enough?
I have Gougeon 5 minute epoxy that I want to use to glue my cut away side to the headblock. Is the 5 minute epoxy strong enough? I don't have that much experience with epoxy. idunno Clinton
Author:  crich [ Sat Mar 26, 2011 4:01 pm ]
Post subject:  Re: 5 minute epoxy strong enough?
Why epoxy? From what I've read here that particular joint may or may not be a perfect fit, and epoxy fills better than hide glue. I HHG everything and it's all I have, besides epoxy, that isn't a few months old. The joint looks pretty good, if I say so myself, but I 'm sure it's not"perfect". :roll: Clinton
Author:  theguitarwhisperer [ Sat Mar 26, 2011 5:48 pm ]
Post subject:  Re: 5 minute epoxy strong enough?
In my experience the shorter the cure time the more rubbery the epoxy, I never use 5 minute epoxy for anything.
Author:  Alain Moisan [ Sat Mar 26, 2011 5:54 pm ]
Post subject:  Re: 5 minute epoxy strong enough?
I glue my end blocks and neck blocks (cut-away or none) with 5 minutes epoxy. I've had no issues with it.

And I can assure you that if properly mixed, it cures real hard (at least the Lepage brand I use).
Author:  crich [ Sat Mar 26, 2011 6:15 pm ]
Post subject:  Re: 5 minute epoxy strong enough?
Yes, I didn't need much working time, good fit. ;) It went fine, only needed 1 minute to clamp. I was concerned with the "rubbery" rumor of 5 minute epoxy. I did a test piece, and oh my, it was HARD after ten minutes. The wood fibers let go, not the glue. Not a very scientific test, I know. I was wondering if there were others that used or had issues with the 5 minute stuff? I feel little better knowing Alain uses it. :D Clinton
Author:  Alain Moisan [ Sat Mar 26, 2011 8:03 pm ]
Post subject:  Re: 5 minute epoxy strong enough?
Good to know I made somebody feel better today!
Author:  crich [ Sat Mar 26, 2011 11:01 pm ]
Post subject:  Re: 5 minute epoxy strong enough?
NOT FUNNY! eek I have nightmares about that kind of stuff ! laughing6-hehe Clinton
Author:  Alain Moisan [ Sun Mar 27, 2011 8:16 am ]
Post subject:  Re: 5 minute epoxy strong enough?
Todd Stock wrote:
The side to neck block joint is one of the most critical to longevity in the guitar...if it creeps or moves in any way, there will be a cascade of other issues to deal with (top shear, neck angle, etc.). Seems to me that a slower curing adhesive with better physical properties for the joint (higher cohesive strength; lower creep; harder cure) would be a better bet. As an alternative, a better fitting neck joint would allow use of the usual adhesives.


I'm not worried about that a single second. First off, compared to a none cutaway guitar, the cutaway itself adds an important amount of strenght to the neck joint area. So whatever glue is used, it will help compared to a none cutaway guitar, which may not even need a neck reset. In addition, I personnally have never seen, nore heard of, a cutaway that got unglued by itself (or even slightly moved) from the neck block.
Author:  wbergman [ Sun Mar 27, 2011 9:40 am ]
Post subject:  Re: 5 minute epoxy strong enough?
Can't remember the brand, but years ago I used an epoxy to repair some parts on the back of chair. After just a few months of use, the epoxy released (not the fibers tearing). So, I guess the lesson would be to use a brand that others swear by, and make sure it is a reasonably fresh product.
Author:  Alain Moisan [ Sun Mar 27, 2011 11:32 am ]
Post subject:  Re: 5 minute epoxy strong enough?
Filippo Morelli wrote:
In other words, what Alain is saying is, he's never heard of a runaway cutaway. laughing6-hehe

Filippo


Fillipo, you're on a roll man!


Todd,

I'm fairely convinced a cutaway joint provides a more sturdy and stable neck joint area. The logic is simple: on a non-cutaway guitar, two glue joints are stressed, which are the top and bottom of the neck block. On a cutaway guitar, there are three. Plus, the inner curved part of the cutaway also contribute to the extra sturdiness (is that a word?) of the neck joint area. So even with a weaker joint, given the end grain factor, an extra glue joint is still an extra glue joint.

Another point to address is what Clinton initially mentioned: it is hard to garantee that the contact surface is perfect regarding a cutaway neck block joint. In the case of a not so good contact between the surfaces, epoxy will do better than any other glue.

Like you said, we'll see 20 years down the line, but I won't loose any sleep over that.
Author:  crich [ Sun Mar 27, 2011 11:44 am ]
Post subject:  Re: 5 minute epoxy strong enough?
Todd, which glue do you use in a cut away? Clinton
Author:  Gtrman13 [ Sun Mar 27, 2011 11:17 pm ]
Post subject:  Re: 5 minute epoxy strong enough?
I use 5 minute epoxy pretty regularly, but only for things such as setting inlays or filling small gaps here and there. It's possible it could work fine for what you need, but there's no way I'd risk it. I don't see any reason why you couldn't use titebond instead, which you know will work perfectly. Every builder is different, but I really don't like to use epoxy an any point that has the potential to have any stress on it whatsoever. Happy building!
Author:  crich [ Mon Mar 28, 2011 10:49 am ]
Post subject:  I called West System-Gougeon
The engineer (tech adviser) stated that the G5 ( 5 minute epoxy) has a strength of 1,000 psi. I feel better. bliss I did ask what would be another product that I could use with a longer curing time, he suggested 105 with a 205 hardener. Clinton
Author:  Alain Moisan [ Mon Mar 28, 2011 2:53 pm ]
Post subject:  Re: 5 minute epoxy strong enough?
Todd Stock wrote:
FWIW, I think most builders think about what will happen to the instruments they make over time.


And I do, just as well. When I said that I won't loose any sleep over that, I didn't mean that I don't care. I meant that I'm confident my neck joints will hold through time.

Just thought I'd better be clear on that.
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