MIMF

Hi,

How about creating a glues overview as a kind of faq or if there is one already somewhere getting it more visible?

I suppose the main ones are:

White/Yellow pva glues
Animal glues (hide, bone, rabbit, fish, edible gelatine)
CA
epoxies

Then maybe
maybe urea based for laminates?
others?

What are the pros and cons of each? Reliable brands in various locations?

+1 on the idea. Could also include strength testing, recommended uses

There was an excellent glue discussion by William Tandy Young on the old forum archives. (He did write the book!)

I agree, a good idea. Also, not that I think Fine Woodworking always gets it right when they do tool tests and post the results on a chart, but a chart seems like it would be really useful for glues, because each one typically does something really well and is really bad at something else. i.e. Epoxy would score a 9 or 10 on strength and gap-filling, 0 on reversibility, hide glue would score 6 to 8 on strength, 1 on gap-filling, and closer to 10 on reversibility. There's also expense, minimum temperature for setting, ease of use, storage life...we could do a survey, no?

Nicholas Blanton wrote:I agree, a good idea. Also, not that I think Fine Woodworking always gets it right when they do tool tests and post the results on a chart, but a chart seems like it would be really useful for glues, because each one typically does something really well and is really bad at something else. i.e. Epoxy would score a 9 or 10 on strength and gap-filling, 0 on reversibility, hide glue would score 6 to 8 on strength, 1 on gap-filling, and closer to 10 on reversibility. There's also expense, minimum temperature for setting, ease of use, storage life...we could do a survey, no?

Actually, epoxy is reversible on areas where heat can be readily applied and releases at about the same temperature as Titebond Original (e.g. fretboards, bridges). Areas such as dovetails are much more difficult if not impossible as it is very difficult to apply enough heat (steam/moisture doesn't help as with Titebond) to get it to release without causing other problems such as neck block release, delamination, warping etc.

Steve Senseney wrote:There was an excellent glue discussion by William Tandy Young on the old forum archives. (He did write the book!)

Maybe that would be a good start or even whole answer if we could get a link to it.

One place to start might be the two short videos on glues that Robbie O'Brien created. Here's the link to the second one: http://www.youtube.com/watch?v=RiDNjGAo1YY

Let me know if this was a help to anyone.

I'd start by advising the use of aliphatics (specifically Titebond I) whenever possible. Titebond is simple, very reliable and not very fussy. It's as strong as any wood glue out there in the right circumstances.
Here are some dos and don'ts:
Do start with clean, fresh, tightly fitting joints. Mating surfaces have to be dead flat to avoid a visible glue line. Glue joints as soon as possible after surfacing the wood. Old, oxidized wood will not glue well.
Do apply to both surfaces if possible.
Do clamp as soon as possible after surfaces are joined, have all clamps tight within 10 minutes (or less in dry conditions or with soft absorbent woods.)
Do clamp as tightly and evenly as possible. Franklin recommends between 60 and 200 pounds per square inch. A vacuum bag will probably not work here.
Do take time to dry assemble and take measures to prevent the joint from slipping as you tighten the first clamp or two. Wet Titebond is very slippery stuff.
Do let the glue set up sufficiently before removing the clamps. One hour at the very least.
On large surfaces do start the clamping at one edge or in the middle and work outwards so that excess glue can squeeze out.
Do wipe up excess squeeze-out with a damp sponge as soon as the clamps are on.
Do sand off any traces of dried glue before applying finish or stain.
Don't use in joints that are likely to experience even modest heat, Titebond will slip or fail.
Don't use in joints that are going to be adversely affected by moisture as in fingerboard to neck or when gluing multiple thin laminates that might warp.

I would suggest including a capsulized version of the discussion on laminating sides (a la Gretsch) from February. Good opinions on appropriate glues.

I'm new but I had the feeling of diaster when I tried white glue on a top craked and loose at the bottom, as the wood soaked up the water, softened and swelled. I rushed clamping. I need to take her apart. When I do it again I'll have a plan using different glues in a temporal order.

Also ... I had to glue nylon to wood once. The local glue genius (no longer here) put me onto some yellow rubbery stuff from 3M. I think it had acetone plasticiser. It set up very quickly. Anyone know what it was, not necessarily 3M, generally?

Hi wblakesx,
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Thanks.

Food for thought: "Which glue to use? A conversation with an expert."
http://dolcecano.blogspot.com/2013_01_0 ... 4274653757

And a post from a Titebond tech rep over on Woodcentral (circa 9/2010):

Regarding empirical data on creep, we do occasionally perform ASTM D3535 "Resistance to Deformation Under Static Loading for Structural Wood Laminating Adhesives Used Under Exterior (Wet Use) Exposure Conditions." Due to intellectual property restrictions I can't post the procedure, but if there's interest I could post a picture of the test apparatus. Our test data on creep resistance from highest to lowest is: Hide Glue, Titebond Extend, Titebond Original, Titebond II, and Titebond III. Aside from difficulty of use, limited open time, and poor water resistance hot hide glue has fantastic properties.

And this from the Titebond website:

What is the shelf life of Titebond Wood Glues?
Our literature states the shelf life of all of our glues as one year. Titebond Liquid Hide Glue includes an expiration date on the bottle, because it can progressively lose its ability to dry hard, and this change is not visually obvious.

Thank you Charlie. That is good information to have.

With regards to using Titebond 3 for guitar building.

I used it on several guitars about 5 years ago and the top joint showed movement in only a few weeks which caused an obvious line in the finish right down the joint. The joint did not open up but it looks bad.

I have built around 125 guitars before trying Titebond 3 and about fifty guitars since using Titebond original without the obvious joint line appearing.

Joel Nowland

Some CA Facts.

We have found that the weakest link in the chain is typically the substrate so strength claims while important aren't an end all and be all determining factor. Ease of use, non yellowing, safer products, glues that allow for techniques which alleviate dust, and other factors make for the "best" glue for any particular situation. We feel strongly that CA glue can take more of a role in guitar building as its strong and now with more flexible types available some new experimentation can be done. Some tidbits below:

1. What is Cyanoacrylate (CA) and how does it work?

Cyanoacrylate is an acrylic resin with an almost instantaneous curing capacity. When CA is introduced to any source of water, it undergoes a process where the CA molecules start linking up into chains and these chains start whipping around to form a durable plastic mesh. The glue thickens and hardens until the thrashing molecule strands can no longer move. CA will adhere to most anything since almost any substrate you may want to glue will at least have trace amounts of water on its surface.

2. What is the shelf life of CA and the best way to keep it fresh?

If properly made and packaged, CA can last two years or more. The bottle that the CA is packaged in is a vital link to the shelf life of CA. Of the many different HDPE resins, there are only a handful that can properly store CA and isolate the liquid inside from the moisture in the air. The cap or closure is also very important to sealing out the water vapors that exist in the air we breathe. A triple seal closure to keep moisture out and the product inside fresh is best.

The handling of the product, once opened, is also very important to the life span of the product. Always keep the cap on when not in use, always keep the nozzle clean from excess glue and contaminants, keep the CA bottle away from accelerators, and store the sealed bottle in a cool dry place. Also, be sure to allow the glue to go back down the nozzle before recapping. This is key to no clogs.

Storing CA in the refrigerator, in an un-opened only container, will keep the product fresh for a long time. Do not freeze CA; 40˚ F is an ideal temperature. Once you first open the bottle, do not put the bottle back into the refrigerator as this will introduce condensation to the inside of the bottle, which will then react with the CA and it will actually start to set up.

3. Why are there different viscosities of CA?

CA comes in different viscosities so it can be used for a variety of applications. Depending on your hand (technique) and how you work, you would be very surprised at how flexible the viscosity can actually be. You just need to go into it with an open mind and not by rote and you can achieve even better builds using less product with better results.

4. What is a Finisher?

CA by its very nature is extremely brittle and cures very hard. While this can often be a very good attribute, there are circumstances where this can be a negative. Take for example cracks or crevices that will move over time such as a guitar ding or dent or even an entire guitar finish for that matter.

Finishers contain specialized market-specific additives to the formula, giving the product the ability to resist age and temperature changes as well as impact. Finishers can be used in areas where CA has been used before but now with increased performance and super clear results as well as in areas CA has not been used before such as to create guitar finishes and repair finish dings and dents.

5. How strong is CA?

CA is extremely strong, with tensile strengths upwards to two tons per square inch not unusual! While CA is not nearly as strong in shear as it is in tensile, most importantly is that a glue joint is only as strong as the substrates being bonded. For example, if you were to bond balsa wood, the balsa wood itself will always break long before the glue joint would fail, no matter what the forces are.

Since strength is really dependent in most cases on the substrate don’t be overly impressed by strength claims. Remember CA Glue can only be as strong as the substrate that is glued. More strength than the substrate can take is simply overkill. i.e., in our business, the substrate is the weakest link - not the glue. Most important is having a purer, safer, fresher, better looking, and are more workable glue, is what counts.

6. Is your CA pure?

Look for CA's that are not industrial remnants or leftovers (as are most current CA products). Look for CA's that actually come out of the reactor at a high 99% + purity level. And watch for carcinogens which are added to many CA's keep them stable. You don’t need that in there for sure.

7. Why does the nozzle on CA bottles always clog and how can I keep them from clogging?

The CA in the tip of the nozzle is reacting with moisture in the small orifice and hardening. Typically once the CA hardens the user will take a pin and stick it down into the nozzle to open it up only to find it clogs up even quicker the next time. What happens is the pin scratches the inside of the nozzle, which allows even more CA to stay in the nozzle causing it to clog up quicker. This process will be repeated several times until the nozzle is no longer able to be used and gets thrown away.

Some companies have claimed to have a clog-free nozzle, which in reality is only a very long nozzle that you keep snipping the clogged end off until there is no nozzle left and still end up throwing it away. Other companies simply sell you extra caps and nozzles so you can replace them after they clog.

Look for an engineered nozzle that not only will not clog but has three different points of seal to assure the product inside is kept fresh and away from moisture. This cap should have a blunt nose, stainless steel pin molded into the cap, which engages into the orifice of the nozzle (not scratching the insides of the bottle) to keep the orifice clean. Inside the tip, a calculated venturie shape, which pulls the CA out of the tip and back into the bottle once the bottle is stood upright. On the very tip of
the nozzle, a tapered seat which engages with a tapered boss in the cap creating compression on the tip of the nozzle keeping the nozzle clean and the product inside fresh.

If the tip is wiped and the cap is replaced each time the user is finished with the product the nozzle will never clog. Also, be sure to allow the glue to go back down the nozzle before recapping. Tapping the bottle a couple of times will help with this. this is very important.

8. What is blooming (or all this white stuff)?

Blooming is the white haze left behind by CA vapors after a glue cures. This is typically caused by a couple of things - excessive adhesive, an inadequate accelerator is used, high humidity in the area, and improper ventilation around the part while the CA cures.

While blooming does not affect the quality of the bond, if blooming cannot be tolerated at all, try using an accelerator product that will not gas or bloom.

While looking at CA's. Look not only for the highest tensile strength available, but for CA's that are market specific, and are not a trickle down from another industry. Make sure your choice of CA adhesives have been thoroughly tested and selected by top luthiers. Lastly, make sure that your adhesives are purer, safer, fresher, better looking, and are more workable glues.

Your CA's should be "surface insensitive". This means they will work on all woods and substrates, while being as strong or stronger than any substrate you will encounter.

A Word about Viscosity, Thin Glues and Their Use

Thin super glue is designed by manufacturers to be used for very close fitting parts, very rapid cure, and for wicking (getting into pores). Thin glues work best for smooth, close fitting parts with little porosity. Most thin glues allow the parts to actually meet and touch preventing a layer of thick glue between the substrates, so that a "glue sandwich" is not created.

The woods used in guitar manufacturing are of very high quality. Because of this, “most" of the tone woods used are not very porous so thin CA glue is employed because it won't totally wick into the wood but will leave some of the glue on the surface for bonding purposes but because its thin it will not leave a gap of glue between substrates like a thick glue would do. This is good, however, other thin glues will “over wick” and not “wet” enough for most applications which can cause overuse simply because these
other thin glues will take a lot more glue to ultimately load the surface to do the exact same job.

Thins that will not only “wick in”, but “wet” better while wicking will enable you to use less and have better results!!

Look for a CA and Accelerator that will not foam, whiten, bubble, haze, yellow, or pit at all - so that you are left with clearly superior results every single time!!!

There are products that are even designed for specifically for fixing dings and dents and for creating a phenomenally resilient finish on any guitar. These particular specialty products are great for drop fills and even deep gash repairs as well as full instrument finishing. This type of product will contain proprietary Market - specific additives that add flexibility without brittleness, so environmental changes and time won’t affect your work. They are also super strong, versatile and makes ding and dent repairs as well as a complete instrument finishing easy and a new add on service for repair shops.

I hope this helps you along in your quest for better products and work results.
_________________
Rick Rosenberg
President
http://www.gearupproducts.com

Good narrative on CA. I can add just a bit or some tips.
With those whip tips, you can take just a square of masking tape and fold it over on itself at the tip. For some reason this works very well to keep the whip-tip functional. Its just a convenient way to do it. Buy the whip-tips in a quantity so you always have them available and toss them the minute they get compromised. Using these can keep the actual original tip of the CA container in good form.

A cleanly cut wound guitar string acts as a very good applicator if you need to place very small drops of CA on a surface. The windings pull up a small amount of glue via capillary action and the smaller the wound string, the smaller quantity of CA the string can transport. This is good for drop filling. I use the bottom side of a small disposable plastic drinking cup as sort of a pallet to keep a puddle of CA on hand for application. You can also take a plastic drinking straw and form one end into a quill to manipulate CA on the surface of your work. Q-Tips do not work for the application of CA. The cotton reacts with the CA. However, a very small drop of thin CA can be wicked up with a Q-Tip but will cure almost immediately so suck up the CA but don't leave the Q-Tip in contact with the work.

Understand that CA will not shrink over time like lacquer will. If you use CA to drop fill a repair in fairly new lacquer, the fill will never shrink while the surrounding lacquer will.

CA works as a very good dropfill on poly finishes with a minimal witness line. Water-Thin CA can wick itself under the finish where the poly finish has separated from the surface. There are situations where CA can totally disappear a fracture by being wicked in a crack in a poly finish.

I often use CA to create a shim under a nut or a saddle. I don't use CA to repair a nut slot. I don't have faith that the CA will be hard enough or yield a smooth enough surface for the string. If nut slots are damaged or too deep, it can be a time saver to pull the nut and create a shim under it using CA applied to the bottom of the nut. I use very thin applications of the CA with an accelerator and build up the thickness little by little and then reform the base of the nut or saddle. You can also use CA to bond a donor piece of bone or Corian to a nut. Rather than repair a too deep nut slot using CA to support a string, you can file a 90 degree "V" into the nut or saddle going deeper than the original slot or damage and then install a 90 degree "V" donor piece of Bone or Corian using CA and reform the donor "V" into the correct shape. I've never had a noticeable tonal result from using a donor "V" bonded with CA.

CA does nut bond very well to some of the slippery modern nut materials such as Tusq and Graphite based plastics. It also doesn't bond well to ABS plastic. I certain situations you can still use CA on these materials by deeply roughing up the surface with coarse sandpaper but understand that the bond is mainly based on the CA being locked into the rough surface scratches.

Paste wax repels CA. Be careful about using masking tape as a protective barrier to CA. Thin CA can wick under masking tape in certain circumstances.

Be careful when using CA in any manner that results is a measurable thickness or depth of CA. Even with an accelerator, CA can cure on the surface yet leave in internal bubble of uncured CA under the surface. As long as you apply CA in small thin quantities, it is a good solid and strong mass. When using an accelerator, CA hardens from the outside inward with a noticeable level of shrinkage. The action of curing is very fast but with any amount of surface area, the curing process is un-uniform. The larger the surface area, the more this un-uniform curing is apparent. If the thickness of the CA is great enough, the surface will cure and slightly shrink so fast that as the surface is hardening it will squeeze out the still uncured CA under the surface resulting in eruptions of blisters and the potential for bubbles of air under the surface. Keeping your applications thin is essential to getting a solid cured mass of CA if you are creating structure.

CA generates heat as it cures. The faster the cure, and the larger the mass of CA, the higher the temperature will get. It will burn skin if there is enough CA and an accelerator. It can also melt finish.

If you accidentally get CA on your skin, it will begin to cure immediately. I have had many incidents with CA including gluing my fingers to the inside of an acoustic guitar and worse. Be intelligent about any incident with CA. The bond to skin is very strong. Be careful about using too much force too quickly when pulling apart a bond to your skin. My thoughts are that the bond is only to the outer layer of skin which is typically a thin layer of dead skin cells. If there is enough surface area and you act in haste, you could rip away enough underlying skin and seriously injure yourself resulting in an injury that could take weeks to heal. Skin oil and sweat tends to reduce the bond. Acetone will assist in reducing the bond further. Its like there is a limited duration that CA will remain bonded to skin. At the very worst, you will be able to very slowly pull the bond apart with only the outer layer of skin remaining bonded to the CA but this can take a fair amount of time (20 to 30 minutes) to accomplish. . My point is, don't panic. In a panic, you can hurt yourself not to mention have an accident on the instrument you are working on.

To make sure you are getting fresh glue check batch numbers on Titebond bottles. Numbers begin like this for example

#A309, etc..

The A means made in America. The 3 means 2013. The 09 means September. So this batch was made September 2013.

Joel

How liquid is your hot hide/bone glue when you use it? If you dip a brush in it, does it run quickly off the brush like water, or is it a more viscous flow? I know it is hard to describe. Recently I met a builder who uses a much more "liquid" glue that I have ever tried. Seems to work fine. May i have been making mine much too tacky.

wblakesx wrote:Also ... I had to glue nylon to wood once. The local glue genius (no longer here) put me onto some yellow rubbery stuff from 3M. I think it had acetone plasticiser. It set up very quickly. Anyone know what it was, not necessarily 3M, generally?

I see no one has answered wblakesx question. The glue was very likely weatherstrip adhesive. 3M makes it in both a yellow and black formula. Usually sold in auto parts stores for attaching rubber trim, moldings and, of course, weatherstrips.

Another group of glues that might have some use for instrument work are the acetone based glues. Duco, Ambroid, Sigment and Testors green tube and brown tube glues. Advantages are a shorter drying time than aliphatic glues and good sandability after drying. Can be unglued or thinned with acetone. Disadvantage, at least of Ambroid, is it's tint, an orange yellow color. I haven't used it for any guitar type tasks, only on model airplanes, so use at your own risk.