Super Glue: Newsletter Challenge (07/04/06)

I don't know Why is a bond with super glue so much stronger than regular glue? but I always had problem with super glue. I bought some tube of super glue and I keep it inside my tools box. After a few weeks or month it become harden not even been used.

The tube that had been used is very difficutle to keep as it get dry up easily no matter how you keep it.

Any help from out there ????

Try closing the tube firmly, inserting it in a ziplock pouch and storing it in the fridge. Have had good results for use between 6 to 12 months period.

Cyanoacrylates are certainly fast, but I've never had the impression that they are stronger than other glues. Part of the action of all glues is the exclusion of the air, and thus the atmospheric pressure - two post-card (100 x 150 mm) sized sheets of glass, when wetted to exclude the air, are held together with a combined pressure of 300 Kg... with water.

Super glues are particularly good on rubber - indeed, early TV commercials showed a rubber hoop cut, rejoined, and dangled from by a gymnast.

This is useful for tired square- or round-section drive-belts in tape-players, etc. Cut out a small section and glue the ends back together - aim well, for the bond is almost instantaneous!

Wikipedia/Super_Glue

Super glues (or cyanocrylates) are fast but have different bond strengths to other adhesives...
They are not stronger in all cases!!

Two part epxoy resin adhesives have possibly the greatest strength...

BUT it depends on your definition of 'strength'..?
Do you mean peel strength, shear strength or what???

Different adhesives are there for different jobs and applications...

John.

For the first time I feel I am smarter than some of the people who replied. Superglue is stronger because as opposed to regular glue, the bonding is by several (multiple parallel) branches of the compound and not by single chain branch of the compound. Hence the additional holding strength. Watch those pesky leakages in the tube!!

From Wikipedia:

Because the presence of moisture causes the glue to set, exposure to moisture in the air can cause a tube or bottle of glue to become unusable over time. To prevent an opened container of glue from setting before use, it must be stored in an airtight jar or bottle with a package of silica gel.

Gluing one's fingers together is probably first!

That led to medical grade adhesives used for surgical procedures both internal and topical.

I agree that "super glue" is not the strongest bond, but it does bond some things very well (i.e., fingers) and it has a fast cure rate.

I was once told to crazy glue a crown that fell out of my mouth back in place with crazy glue by a dentist. Decided to NOT do that with all the "DO NOT CONSUME" warnings on the label.

I did glue my wife's crown back on. I used ethyl alcohol to clean the post and socket first then 1 drop of glue. When my wife went to have it repaired, the dentist couldn't get it off. He said he was afraid of breaking the tooth!

As noted above Super Glue's strength depends on what force it is counteracting. It is extremely strong in Tension (mostly straight pull force), as demonstrated on TV by the guy who hangs from a steel beam his hard hat is glued to (actually, there is a block on his hard hat, providing a good flat surface).

Super glue, Cyanoacrylate, or CA, is not as strong when resisting peeling (peel strength), or twisting or sliding forces (shear strength). Its high tensile strength probably comes from the very long chains it forms when the liquid glue polymerizes with water to form the solid. Because of its very low viscosity as a liquid, it spreads very quickly at the surfaces of a joint, and so bonds quickly when repairing broken objects. However, the same low viscosity prevents it from effectively bridging gaps and filling holes in porous or non-flat mating surfaces.

The medical, industrial, and hobby uses have already been noted. I have used super glue effectively to hold small zinc weights in Pinewood Derby race cars, primarily because of its fast setting for on the fly repairs. Also, because it is NOT very strong in shear, weights can be more easily removed by twisting them with pliers if needed. Because of the brittle nature of the bond, a good, clean break is usually obtained, allowing the metal to be easily reglued after some weight reduction.

Has anyone tried using super glue on electrical connections instead of soldering? I would think that the exclusion of oxygen would maintain a good electrical connection, as long as no glue came between the contact points. It should work very well with crimped connections, where the mechanical strength might otherwise be compromised by vibration or temperature variation (expansion/contraction).

Its stronger because it forms polymer chains that entwine themselves whenever the uncured acrylate ester encounter hydroxyl (water) on/in the surfaces of the materials being joined. On our planet at STP, thats just about everything. Other glues in the past were the reverse- they required water -or some other solvent to evaporate OUT of the Glue. The combinations of all of the molecules starting to polymerize at onec, randomly oriented creates an non direction strength (isotropic)based on the entanglement of the polymer chains. I would not think that an organic polymer- think plastic- would be suitable for electric connections since plastics and organics in general are insulators - dielectrics at best. Milo

Milo,

You are correct in that the glue itself is a dielectric (insulator), however it could be useful when used in conjunction with a mechanical crimp connection, where the two (or more) conductors are squeezed together to make good surface contact. The intent of the crimp is also to exclude air which would oxidize the metals, the oxides normally being nonconductors or at least poorer conductors than the metals. Too often the mechanical strength of the crimp does not hold up under operating conditions which can include tension, vibration, and thermal stress through expansion and contraction. Chemical deterioration can also take place, even creeping into the contact area from outer surfaces. Super glue, acting as both an adhesive and as a sealant could prevent such contact deterioration.

Obviously, superglue alone should never be used to replace soldering, crimping or other electrical joining operations, but it could enhance them. There are some glues with conductive qualities, usually using metal fillers, and these might include CA or other adhesives as a component.

You clearly are looking more deeply at the proposal to use superglue for electrical connections than I did. Super glue as the adhesive per se- No crimp or other means mentioned by the earlier post- seemed doomed to failure. You make an excellent point regarding its use as a sealant as one part of a system of connection. But sealant is not the same as adhesive. I agree with your analysis. Milo

I had slashed open the backside of one of my fingers with a knife and was miles away from medical attention.

It was approximately a 1 inch (2.5 cm) long laceration from the first knuckle down through the second knuckle of my right middle finger.

After cleaning the the cut with available potable water and putting pressure on it with a bandana to stop the bleeding. I then held the gash together, and liberally applied CrazyGlue™ over the top of the wound, taking care to line up the edges. It held the cut closed for about two hours, long enough for me to properly care for it, later that night.

As the operational motto for the Marine Corps goes... Adapt, Improvise, Overcome! I actually ended up with a fairly small, clean cut and was commended by a Corpsman friend who said that was good thinking.

Semper Fi. Al

I have also done this with good results. My preference is paper surgical tape. If you can get things lined up and sealed up right away, it seems to greatly speed the healing time. Bandaids are a joke!

Wasn't it designed for just this eventuality? I heard that is was developed by the US in response to military requests for a speedy "field dressing". All the other applications came later.

No. A CA spray was developed for that reason though.

I used superglue to harden the surface of a little RC aircraft propeller I carved out of balsa wood. It completely changed the characteristics of the material to something light, tough and waterproof.

Won't acrylic spray enamel (Krylon, etc.) do that as well?

How did you apply the CA, with a brush? I would think you could have got a smoother surface (better aerodynamics, more efficient) with a spray.

Superglue and an empty fishtank are good for revealing fingerprints. Veterinarians use it to repair animals. Button fall off? Just superglue it back on. Not only is it a product name, but it can be used as a verb. (see above sentence) Superglue can be used for numerous pranks. (If you're ever a victim, nail polish with acetone will save you, with patience and diligence you can avoid that embarrassing hospital visit) BTW, Superglue is one of those accidental inventions. Scientists were trying to come up with a new kind of plastic for aircraft gun canopies during WW2. Neat-o stuff!

No one has mentioned that SuperGlue makes an excellent wood finish. I read an article in a wood turning magazine about using it to finish turned bowls. It dries hard, waterproof, and dishwasher safe. I haven't tried it yet but it sounds cool.

I realize this is an old thread but just had to comment. My hobby is knife making and I have been using Superglue to finish my fine natural wood handles for years. It is one heck of a finish. With subsequent coats and progressively finer sanding the finish looks wet. It is extremely hard and as far as I can tell waterproof. Great stuff for this application.

By the way – if you are going to try this at home do so in a well-ventilated area and use reasonable caution. The fumes will send you to Pluto, and if you use paper towels to swab on the glue they will become hot enough to smoke as the glue reacts. And of course, watch that exposed skin!

Does anyone out there know why it is that superglue doesn't seem to stick to Nylon as well as it does to say ABS? We're using a "shock resistant" variety of superglue (which apparently has embedded rubber particles as part of its make up) to stick small metal plates to nylon moldings. Performance isn't so good in drop tests.

Question: Why is a bond with super glue so much stronger than regular glue? And do you know of some unexpected uses for the product?

Answer: Super glue gets its bonding strength from its main ingredient, cyanoacrylate, an acrylic resin that cures (forms its strongest bond) almost instantly. The only trigger it requires is the hydroxyl ions in water – not a problem, because virtually any object you might wish to glue will have at least trace amounts of water on its surface. Super glue undergoes a process called anionic polymerization, in which the cyanoacrylate molecules link up when they come into contact with water. The molecules move in chains, forming a durable plastic mesh. As the glue thickens and hardens, eventually the molecular strands can no longer move, resulting in the super bond.

Some unexpected uses of super glue are to close wounds instead of stitches and super-glue fuming to detect latent fingerprints. (The object being checked is placed in a heated, airtight container. Cyanoacrylate is added; as it evaporates and is circulated throughout the container, it reacts to materials that may have been left behind, making the fingerprints visible.)

When my huband and I were at Queen's University a researcher from industry was using our SEM to investigate failures in the wires of cochlear implants. The failures seemed to occur mostly in children. What he discovered was that during the process of installing these devices, a little cavity is made in a bone in the head, the device is implanted and cyanoacrylate glue is then used to fill the cavity to ensure the device stays put. Some doctors didn't like putting the glue in someone's head, so they didn't. Children tend to be active, running and jumping around much more than adults; the net result was fatigue fractures of the wires, which then required further surgery to correct.

Water is an important activator in the bonding process of cyanoacrylate glue, which is why it bonds so well to skin, eyes, mouth, etc. Usually, most materials have a thin layer of physisorbed or chemisorbed water, which is what allows the bonding to occur. Sometimes, when trying to glue parts together with crazy glue, the bond just doesn't seem to "take". If this happens, just rinse the part with water, dry with a cloth and try again. This time, be sure you fit the parts together perfectly as you won't get another chance.

I kept losing a crown and paid hundreds of dollars having it recemented. I looked up glue and crown on internet and found out that super glue was not toxic and had been used in dentistry before. I dry my crown carefully, my mouth ,used one drop of superglue and put it back in place. There is a type of glue that comes in gel form and will not run. I t is great and feels really strong even better than when the dentist had recemented it. It cost me $7.00 instead of $95.00