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How long do you leave fan braces clamped in a go bar deck before it is safe to shape them?
Thanks, Wendy

What kind of glue?

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Waddy

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Overnights okay no matter what glue. Hide or Titebond....Mike

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Another day, another dollar.

I try to time it so it is the last thing I do before calling it a day. I use hide glue on braces. I leave them, at least, overnight.

Two, three hours, glue is set.

It's Titebond. It's just that I only have weekends to work on it and, since they have to be glued and carved in stages, it stretches it over a couple of weekends. I'm always nervous about maintaining the humidity over a long period when the weather is unpredictable this time of year. I usually do assembly either in the summer, when I have an easier time controlling humidity, or over the holidays when I have a stretch of time available. Oh well, sounds like overnight for clamp time is safest. So far the forecast is stable.

Hi, Wendy,
I guess it comes down to what is practical for you. I'm a weekend worker, too. Given your concerns, maybe you can stage your work flow so that you can glue braces just before stopping on a Saturday, then shape them when starting on Sunday.
Different glues require different set times in different shop temperatures. But I don't think you can go wrong by leaving the braces clamped overnight, regardless of the type of glue. It might not be necessary, but it isn't going to hurt.

More clamping time, say overnight is fine but not necessary provided that you don't stress the joint.

For either Titebond original or HHG I may remove clamps or go-bars in as little as four hours but again I won't stress any structural joint for 24 hours. In addition this is with near perfect environmental conditions as well, RH between 40 and 50%, temp of 70F+, the sun shining outside, bluebirds chirping at the window sill and no I am not high.....

When gluing radiused braces in a dish the glue joint will be under tension when the clamps are released. I've always felt glue was weakest under tension so I usually error on the side of safety and leave them clamped overnight or around 12 hrs. Hide or Tightbond. May be overkill but what's the downside? There's always other stuff to do. Work on your neck or make a bridge or fretboard.

I don't usually voice the top braces until I'm ready to glue the top within a relatively short period of time.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I am working on getting my braces in order, so this is a timely thread for me!

I do have a question about glue, if I may.

Both HHG and Titebond have been mentioned, and I was wondering if there's any real value in the white instrument makers glue like the stuff sold from LMI vs Titebond. I understand the differences between using HHG and wood glue, but I'm wondering if Titebond is just as good or better than the LMI glue. Original Titebond is less than half the price, and I don't have to pay for or wait for it to ship.

What do you guys think about the LMI white glue? I used it to join my top and back when I first got it, and then used the rest on various other projects so I need to buy some more glue.


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Justin LMI's glue is great stuff. IMO it dries a bit harder and more crystalline than say Titebond original.

On the other hand millions of successful guitars have been built with Titebond original and it's also serviceable, a very high on the list consideration for me in that it releases with heat if we wish.

The one down side of Titebond is cold creep which only is a potential issue for us, guitar builders, with bridges. Although many folks here will not agree on the cold creep claim we've seen it ourselves a number of times where over time and with string tension a bridge may slide forward plowing finish and exposing the glue line on the back edge of the bridge.

Back to LMI glue. Great stuff provided that you have unfettered access to it and what I mean by this is that for the rest of we mere mortals who are not fortunate enough to live on the west coast... we have to have our LMI shipped to us. If the stuff freezes during shipment it's ruined and useless. It also IIRC correctly has a usable shelf life of less than Titebond of six months to Titebond's one year.

These days ordering a package from one place with the hub system of logistics employed by vendors there is no telling how our shipments may be routed or where. So to me this means that say after October in any given year and for those of us in cold weather climates we can't know if our LMI glue has been exposed to freezing temps and ruined.

As such I use Titebond original for many tasks and HHG as well where the benefits exist and certainly for bridges, braces, bridge plates, necks, etc.

I've wondered out loud on the OLF before about if....... those who came before us in the pre-technology days of Lutherie had access to Titebond original might it have been a standard of the industry as well as HHG?

I like it. I used it for everything 10 years ago and I still use it for gluing the end blocks, lining, and closing the box. I have not had any issues. Best not to have it shipped if temps are below freezing and keep an eye on the shelf life. (Whoops Hesh covered that )

Tim McKnight did some testing a while back. Much discussed on the forums at the time. Interesting stuff.

http://mcknightguitars.com/glue-hardness.html

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Thanks Hesh and Terence. I had read that post by Mr. McKnight about a year ago, and it was good to read again to refresh.

I am convinced that HHG is great stuff, but I'm intimidated by it to be honest. I'm still working on my first build, and the idea that I can't easily fix problems is off putting at the moment. But at the same time I want to build the best sounding instrument possible.

Has anyone used fish glue? I know it's available from Blues Creek, and from what I've read it sounds like a happy medium between HHG and white/yellow wood glue.




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Hesh: While I don't doubt you have seen what you are telling us about, I doubt is was so called cold creep. I think most likely there was excess heat involved in some fashion. Have been using Titebond and other aliphatic resin glues since the mid 70's and I have not seen one case of creep. Maybe weather is a factor. Here in the Maritimes we don't get extremes of temperature that guitars may get exposed to further south............................Hesh just trying to validate your claim of nay sayers in regard to the cold creep. You can buy me a beer later. Anyway this has been my experience for what it's worth. Take care.
Tom

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Wendy, the instructions on TB say 30 min clamp time, no stress for 24 hrs.

In terms of the amount of stress in a flexed top in a radius dish trying to regain its flatness against the braces, that stress is negligible. 30 minutes is more than enough to remove from the deck and work it, in fact 15 minutes is enough too.

Take three brace scraps and top scraps and put em in the deck. See if you can separate them at 10, 20, and 30 minutes without a hammer. Bet you can't...

So, 30 minutes is ample time for clamping Titebond and LMI white.

LMI white is a good glue, but I see no real advantage to it over Titebond. Not enough to pay the import fees on it, which is actually ridiculous since it's made in Canada. But whatever.

I've been using the Rainbow yellow glue that Larrivee has custom made for him for the last pile of years. Now there's a Yellow glue with a difference! Shame they won't talk to you for any less than 500 gallons. Group buy, anyone?

So, from here on out it's Titebond for me.

Tom my friend I already owe you at least a case for all that I have learned from you over the years!!!

Climate does play a role IMHO in terms of glue selection. Here in Michigan we can have 100F+ summers (even hotter lately....) and very hard, long, cold winters. So folks in these parts get into trouble with the care and feeing of their instruments and may leave one in the trunk of a black car in the long term at DTW....

So we see cold creep at times, perhaps I should call it hot creep.... almost always on bridges.

If my thoughts on LMI gave anyone the impression that it's not great stuff that was not my intent or what I said. For me, where I live, it's problematic to get because of shipping and the weather and seasonal changes, that was the point. It also does cost more, shipping costs even more, and in my business I can't be waiting for glue when I promised my repair clients an ETA on their wounded instrument. I like it fine and would use it perhaps even over Titebond if I could simply buy it where I am.... and when I need it.

Justin asked about Fish glue. Years ago this forum was pretty much introduced to fish glue by a very few fish users at that time. My business partner, David Collins was perhaps the most prolific about sharing what he knew at that time about fish glue. The archives will provide the details.

We, David and I, stopped using fish about five years ago because of bridge failures that had been reglued with fish. There were a number of these failures including across more than one batch of fish glue from Norland. We are also fanatic about freshness and the care and feeding required by the various glues. I even seem to recall David updating the forum more recently that he was no longer using fish for bridges.

A few weeks ago one of our clients showed up with a lifted bridge on a D-18 that had also been reglued with fish.

I'll also point folks to the recent post by someone in Florida I believe who had had it up to here with fish and had some failures too. His was not the only post about fish glue failures on the OLF that I can recall with my steel trap memory.... er, what was I going to say...

Anyway I think that fish is fine for non-structural stuff but we have to stand behind our work and gladly do so at all costs and this means that once a material or glue proves to be less than stellar at what we intend to use it for it's out the window....

Now again I understand that some folks here may not have had this experience and I sincerely hope that you never do. I also understand that some are vested in and wedded to fish because of the realistic promise of near-HHG-like crystalline glue joints without the hassle of the short open time of HHG. That was the attraction for me too.

But at the end of the day if fish can give way in high RH and has done so now with many documented examples on this forum alone who needs it?

I'm a builder who makes most of my living repairing mostly guitars but all manner of plucked, stringed instruments. For my own creations if a glue can't do the job I find another glue. In our repair business when some of you folks who sell your stuff have bridge failures folks such as I make more money fixing what went wrong and we also get to hear how Mr. and Mrs. Customer feel about it as well.

Not trying to persuade anyone to drop fish because that is completely up to you. But for us with lots of experiences with it over long periods of time fish is questionable in it's ability to withstand periods of higher RH. And, depending on where you live or where one of your creations may end up this should be important information to you, considering...

But feel free to do what ever you like, I just might make more money because of it....

PS: I also never liked how fish cleans up, it's stringy, messy and reminds me of cotton candy....

PSS: Our friend Med makes a great point - don't be afraid to test stuff out yourself. Perhaps put a sponge in a garbage bag with a fish glued joint, a Titebond glued joint, and a HHG glued joint. Leave them in the bag for about a week and then test the joints. The bag will likely be about 75%RH so it's a good simulation.

I tend to respectively disagree. Where the dome is held soley by the shear strength developed along the glue line, by 5 or 7 very thin (maybe 3 to 5 mm wide) fans, it seems prudent to let the glue fully cure to crystalline hardness before unclamping.

Joe

Crystalline hardness doesn't occur with TB. It remains fairly flexible when dry, or it did in all my tests.

_________________
Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Hmm, it may not be the best choice for gluing fans to create the dome then. LMI white and HHG both seem to achieve crystalline hardness, at least in my tests.

Joe

LMI white does get hard.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I know your doing a classical, but for steel strings, I unclamp and carve my braces 30 minutes after gluing and clamping with TiteBond. I use a very thin, non-opaque layer on the brace, rub it onto the soundboard a little to "set" it, and clamp. I've never had any problems with the curved braces coming unlued, I don't think the stress is enough to harm the joint. I can't imagine the situation is too different for classicals.

I glue the bridge patch and upper transverse patches,

then I glue the soundhole braces and fan braces at the same time, carve them, glue the lower face braces and upper transverse brace, carve them, then glue the x-braces and carve them.

Takes about 4 hours.

If I'm feeling especially industrious I do the back braces at the same time while I'm waiting for the glue to dry on the top braces.

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For those interested in how Fish glue withstands high RH I'm currently undergoing a test with the glue at 75% and 85% relative humidity.

http://www.classicalguitardelcamp.com/v ... 11&t=84987

So far it seems to be perfectly fine at these levels.
I'm also doing a test to see how it withstands string tension (over a period of time) @ 100 Kg. That's more than double the tension found on your average Classical Guitar.
The two tests are separate. One day I might combine the two i.e. high string tension + high humidity and heat. At the moment they are sat at a cool 18 centigrade.

I always have to applaud folks for doing testing! Great to see and thanks for posting this Michael.

However.... if you read the thread that you linked us too Alexandru's comments are notable and his assertions about the orientation of the pieces that you have glued together takes into account a more "real world" view of what a guitar, considering how they are assembled, has to deal with.

In addition we are not looking for data to support a conclusion that when we dip a guitar in a high RH environment a glue joint may fail. Instead, in my view RH and temp are cyclical in the real world meaning that there can be exposure to higher (and lower) temps and RH and it is this cyclical nature of the real world that also plays in importantly to Alexandru's comments regarding the grain orientation of the sample pieces. Cycles of change are needed to glean the disparate expansion rates of the various woods in various orientation.

Of the fish failures that we saw and still see, saw one two weeks ago, the joints did not fail at once. The first batch of failures were approx two years out and then we continued to see them now 5 - 6 years later. In this time the seasons have changed a bunch of times and that cyclical nature of the real world that I speak of was happening all the while.

Again use fish if you like it just be aware that for some things, bridges in particular, there have been reported failures and our shop is not the only one reporting the failures.

I was glad to see, Michael, that you employed more tension than a classical guitar is subjected to. Your 100 kg is more inline with what a steel string sees and let's remember too that most here on the OLF are building steel strings with this higher string tension.

I was thinking of how I might design my own test and it gets complicated real fast.... I envision an actual guitar body in a fish tank with string tension and environmentals that cycle as our very own weather does. Not easy to conduct and I also suspect that the test should be run for at least the minimum time before failure that we have observed in the real world examples or two plus years. This takes space too, monitoring, diligence, and perhaps more.

Might just be easier to use HHG for bridges or, as mentioned, we will be happy to reglue the bridges that come off in time and bill accordingly, makes no difference to me...

I fail (pardon the expression) to see the relevance of grain orientation. If Fish glue fails, it fails because the glue softens. If you look at the Fretboard failure on Alex's Guitar you will see 'strings' of glue. This indicates that the glue reconstituted but did not fracture.
It's indicative of high humidity or both high humidity and heat. He had the Guitars in a newly built house, without the use of dehumidifiers. The only way heat would have been a factor is if his friend had the heating turned on full blast or they suffered a heat wave.
By itself heat seems to do very little to Fish glue. In fact I tried to remove a fretboard that had been glued with Fish glue and it was much harder to remove than one glued with HHG. It can take heat.
The high humidity coupled with heat is for another test but bear in mind that most glues will fail that particular test. The relevant question becomes at what level. Both Titebond and HHG will fail, otherwise we would never be able to release joints for repair purposes. If Fish glue survives at 85% RH @ 35 C I think I might deem that acceptable. Those are both figures off the top of my head. I haven't really thought on what I consider acceptable. There's only so much that a Guitar can take, the rest would (and indeed should) be considered outright abuse. If we really were building with a glue that can take 99% RH and 99 C we would all be using Urea Formaldehyde.

I don't use a go bar deck I use clamps but it's the same principle. 1 hour with Titebond or LMI and I've never had a problem. But then I don't go into carving them or messing around with it for at least over night so like 12 hours. I've started using fish glue for more applications and the long dry time of that does bother me a bit but it's fantastic stuff.