Interesting Repair Technique – NaHCO3 + SuperGlue

This could in general be very useful, but also in an emergency situation is nice to know. There’s superglue and baking soda everywhere!

The basic effect is that baking soda, added to superglue in 1/8 inch or so layers, makes a very hard plastic. Good for surface repairs, wood filler, etc.

The one video has the stupid title “click bait” about “cops don’t want you to know” – but frankly I think it would be better with “easy way to fix things”.

The other has a guy “muff” it by packing a space with powder and dribbling superglue on top (leaving the center still powder) but gives a good idea how deep a layer you can do at any one time:

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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17 Responses to Interesting Repair Technique – NaHCO3 + SuperGlue

  1. jim2 says:

    I’ve used this because sometimes superglue doesn’t set very well. When you sprinkle on the baking soda, it sets up immediately.

  2. Larry Ledwick says:

    Another thing that helps super glue set it moisture, if you wash the items with alcohol, the clean oil free surface with a molecular layer of moisture bonds very fast in my experience. Any time it is important for super glue to stick and bond instantly and strongly I use and alcohol prep just before I add the glue and press things together.

  3. jim2 says:

    I almost always use isopropanol to clean joints before using superglue. I use IPA for a lot of cleaning chores.

  4. andrewsjp says:

    This is used all the time in guitar repair. See: https://www.youtube.com/watch?v=sJChDNCjJ5I

  5. jim2 says:

    Thinking about all this a bit more, for cleaning I use 91% IPA. It will suck the water right off any solid surface. I will try 70% for superglue joint cleaning next time around.

    91% IPA will suck the water out of a paint brush cleaned with water and dries quickly. I usually do 2 rinses.

  6. Larry Ledwick says:

    I mostly use 70% rubbing alcohol but also have the higher concentration. I found out how it helps once by cleaning two pennies with alcohol and putting a drop of super glue on one and pressing them together – – – I never could get them apart it was a very permanent joint.

    One other helpful tip on super glue – to keep it long term store the tubes in the freezer.

    https://lifehacks.stackexchange.com/questions/4061/how-should-i-store-super-glue-to-prevent-it-from-drying-out

    I also use the freezer to store other glues that tend to harden over time, like shoe goo.
    I close the tube put it in a small zip lock bag and toss it in the freezer. The cold temps slow down chemical reactions and reduces vapor pressure of the solvents in the glues so there is essentially zero evaporation of the solvents. Then when you need it you just take it out and let it warm up to room temp.

    For the shoe goo, I just drop the tube in a cup of room temp water and come back in about 10 minutes or so and it has warmed up enough to use it.

  7. Larry Ledwick says:

    I mostly use 70% rubbing alcohol but also have the higher concentration. I found out how it helps once by cleaning two pennies with alcohol and putting a drop of super glue on one and pressing them together – – – I never could get them apart it was a very permanent joint.

    One other helpful tip on super glue – to keep it long term store the tubes in the freezer.

    https://lifehacks.stackexchange.com/questions/4061/how-should-i-store-super-glue-to-prevent-it-from-drying-out

    I also use the freezer to store other glues that tend to harden over time, like shoe goo.
    I close the tube put it in a small zip lock bag and toss it in the freezer. The cold temps slow down chemical reactions and reduces vapor pressure of the solvents in the glues so there is essentially zero evaporation of the solvents. Then when you need it you just take it out and let it warm up to room temp.

    For the shoe goo, I just drop the tube in a cup of room temp water and come back in about 10 minutes or so and it has warmed up enough to use it.

  8. E.M.Smith says:

    Thinking about this, I wonder what the chemical reaction is? I doubt the sodium hydrogen carbonate is just inert filler. I could see the H and Na taking the role of water in the normal catalyzing or perhaps have the carbonate form bonds between acrylates. Or the cyano triple bond might be opening up to make polymerization bonds with just about any of it…

    I’d expect other carbonates to work too. KHCO3, K2CO3, Na2CO3 and CaCO3 (lime) and maybe even CaSO4 (gypsum). A lot of fun could be had here trying and testing different options…

    The Wiki says it happens, but doesn’t elaborate on the chemistry. It does include CaO as working:

    https://en.wikipedia.org/wiki/Cyanoacrylate

    Filler
    When added to baking soda (sodium bicarbonate), cyanoacrylate glue forms a hard, lightweight adhesive filler (baking soda is first used to fill a gap then the adhesive is dropped onto the baking soda). This works well with porous materials that do not work well with the adhesive alone. This method is sometimes used by aircraft modelers to assemble or repair polystyrene foam parts. It is also used to repair small nicks in the leading edge of wood propeller blades on light aircraft,[9] although this technique is limited to use on aircraft registered in the “experimental” category (composite propellers can be repaired in a similar way using two-part epoxies[10]). This technique can also be used to fill in the slots in the nut of a guitar so that new ones can be cut. The reaction between cyanoacrylate and baking soda is very exothermic (heat-producing) and also produces noxious vapors.

    One brand of cyanoacrylate, “SupaFix”, uses calcium oxide as a filler giving an even harder (mortar-like in texture) result that can be used to join hard materials and even repair cracked castings.

    They describe the polymerization process (normal setting) as leaving the CN triple bond intact. They mention hydroxyl radical as the catalyzing agent. Showing “Nu-” as the trigger. Nutrophile? Nucleating negative? So that would imply CO3- – as a similar agent or perhaps NaCO3- and the rest of the polymerization the same.

    This is a bit intriguing. Basically saying it reacts fast and a lot with these materials, but not saying if you get a useful final product:

    Reaction with cotton, wool, and other fibrous materials
    Applying cyanoacrylate to some natural materials such as cotton (jeans, cotton swabs, cotton balls, and certain yarns or fabrics), or leather or wool results in a powerful, rapid, exothermic reaction. This reaction also occurs with fiberglass and carbon fiber. The heat released may cause serious burns or release irritating white smoke. Material Safety Data Sheets for cyanoacrylate instruct users not to wear cotton (jeans) or wool clothing, especially cotton gloves, when applying or handling cyanoacrylates.

    They say it is used with sawdust for filling wood.

    I wonder what it would do with rock dust… or fine sand…

    I could easily see uses for a thin layer spread with a plastic scraper, then a single thickness of glass fabric laid in it. Instant fiberglass surface. Then coat with some epoxy for a surface finish if desired. A single layer of glass over surfaces like metals or ceramics ought not care about any heat and a thin enough layer has a lot of cooling surface area.

    I’m thinking there’s an opportunity for some kind of 3-D printer that sputters CA glue from one nozzle and dusts from another to sculpt things rather tough and stone like…

  9. E.M.Smith says:

    Looks like others thought of 3D printing too. But as drips of glue into a powder bed.

    https://reprap.org/forum/read.php?88,284353

  10. Larry Ledwick says:

    The other interesting idea is how rapid is the reaction and how temperature dependent?

    My thinking is if the glue and bicarbonate are cold enough do you have enough working time to mix and pour in a mold?

    Second is the catalytic reaction once started move through the body of the CA glue or do you need to mix the two components to complete the reaction through out the mass or does the bicarbonate dissolve in the CA and quickly merge into a uniform mixture?

    Certainly worth playing with a bit and to keep in mind when you need a quick instant set filler.

    What happens if you mix the bicarbonate with water or alcohol to form a paste or super saturated solution and then mix with the CA glue?

    From the video it looks like no attempt is made to mix the two only introduce the Bicarbonate by dusting the surface to trigger the reaction.

    https://www.popularmechanics.com/science/tips/a584/2569841/

    what happens when you mix bakingsoda water and superglue

    quick demo of use in model repair

  11. Larry Ledwick says:

    Good description of the chemistry of super glues.

    https://www.ipmsstockholm.org/magazine/2004/10/stuff_eng_tech_ca_glue.htm

  12. E.M.Smith says:

    Good point on the temp thing. The wiki states that below freezing the reaction rate of plain CA drops to near zero (so storing in the freezer gives extreme lifetime instead of 1 year expired – as you noted too). This implies a very cold mix ought to have some work time.

    The counter point is that this rapidly warms on setting, so there’s an exponential here. As any amount of reaction happens and raises temperature a bit, the reaction will go faster, raising it more, speeding it up, heating faster…etc. etc. SET. So there may be some very cold minimum needed to have work time.

    The “sawdust as filler” part of the wiki said that you could adjust the setting rate:

    Woodworking
    Thin cyanoacrylate glue has application in woodworking. It can be used as a fast-drying, glossy finish. The use of oil, such as boiled linseed oil, may be used to control the rate at which the cyanoacrylate cures. Cyanoacrylate glue is also used in combination with sawdust (from a saw or sanding) to fill voids and cracks. These repair methods are used on piano soundboards, wood instruments, and wood furniture. Cyanoacrylate glue is also used in the finishing of pen blanks (wooden blanks for turning pens) that have been turned on a lathe by applying multiple thin layers to build up a hard, clear finish that can then be sanded and polished to a glossy finish.

    Though I wonder what it does to the strength.

    Trying to mix a wet paste of bicarbonate with CA is unlikely to be helpful… The water starts the polymerization chain of events that will travel through the drop of CA (as normally) faster than the CA can move into the body of the NaHCO3 + H2O that has no pores for traveling….

    To facilitate easy handling, a cyanoacrylate adhesive is frequently formulated with an ingredient such as fumed silica to make it more viscous or gel-like. More recently, formulations are available with additives to increase shear strength, creating a more impact resistant bond. Such additives may include rubber, as in Loctite’s “Ultra Gel”, or others which are not specified.

    In general, the acryl groups rapidly undergo chain-growth polymerisation in the presence of water (specifically hydroxide ions), forming long, strong chains, joining the bonded surfaces together. Because the presence of moisture causes the glue to set, exposure to normal levels of humidity in the air causes a thin skin to start to form within seconds, which very greatly slows the reaction; hence, cyanoacrylates are applied as thin coats to ensure that the reaction proceeds rapidly for bonding.

    Cyanoacrylate adhesives have a short shelf life—about one year from manufacture if unopened, and one month once opened. The reaction with moisture can cause a container of glue which has been opened and resealed to become unusable more quickly than if never opened. To minimise this reduction in shelf life, cyanoacrylate, once opened, should be stored in an airtight container with a package of silica gel desiccant. Another technique is to insert a hypodermic needle into the opening of a tube. After using the glue, residual glue soon clogs the needle, keeping moisture out. The clog is removed by heating the needle (e.g. with a lighter) before use.[citation needed] The polymerisation is also temperature-dependent: storage below freezing point of water, 0 °C (32 °F; 273 K), stops the reaction, so keeping it in the freezer is also effective.

    So my expectation is the drop will hit the wet paste, make a “skin” and now you have a drop of CA sitting on a hard layer over a drop of mushy wet paste…

    My guess is that the hydrogen carbonate ion takes on the role of the hydroxide ion, the “Nu-” in the wiki chart, and that the Na+ takes on the role of the H+ as a chain terminator, with some amount of the NaHCO3 just acting as tiny dust rock bits embedded in the final polymer. Why? Because if you got it all to react in a balanced mix you would not get polymer but a Nu- addition on one side of the monomer and a Na+ termination on the other. (OTOH, maybe that gives you a hard molecule?… but I doubt it.)

    It is also possible that the HCO3- dumps the H+ also and can be bonded to TWO CA molecules, so starting TWO polymer chains joined via a -OC=OO- bridge… Which would explain a lot as it would not just initiate polymerization but also join polymer strings at that bond. In which case using Na2CO3 might work even better (IF the Na+ is not as effective a chain terminator…) or CaCO3 could be very great as the Ca+2 would ALSO tend to cross link polymer chains at the “termination” end (which instead of terminating the total polymer, just terminates the CA to CA bonding and puts a CA-Ca-CA bridge in place instead…)

    So I’m really interested in trying a chalk filler. Maybe marble dust from a masonry cutter? Oh, wait! I have some dolomite pills. Crushed dolomite ought to be interesting. (Mixed Ca and Mg carbonates)

  13. jim2 says:

    The article mentioned -OH as the active agent in water – a base. Baking soda is also a base, and a stronger one than water. Along that line of thought, amines, lye, and a number or other bases should also work. Acids should also work. Will have to try that :)

  14. E.M.Smith says:

    Larry’s link (stockholm) says that sulphonic acid is added to CA glue to STOP it from reacting in the tube and it’s the neutralizing of that acid that lets it set. To the extent that is true, acid will not make it set faster…

    The wiki says you need a negative (Nu-) to start the catalysis. I think this pretty much says you need neutral ions (water) or more alkaline / basic.

    HOWEVER: As this is an organic polymer with both acid and base join points, it might be possible to run the polymerization from the other end. Maybe…. But it would require an acid strong enough to put enough charge on that H2=C bond to pop off one of the H+ ions. I think that’s going to take something strong enough that other “side reactions” are going to muck things up.

  15. jim2 says:

    Yep, looks like I called that one wrong – no acids!

  16. Larry Ledwick says:

    Another idea that popped into my head while thinking about this is to dust one face of a joint with Bicarb (very thin) and then press the joint together – should get a zero working time immediate join especially in warm temperatures. If you pre-chilled the pieces being joined you might get just a second or two of working time for final position.

    Glass micro-spheres would be another interesting filler to play with.

    The other thing about the effect of moisture is your working time would change with daily humidity in your location (ie rainy day projects would set fast, and hot dry desert conditions would lead to slow bonding.)

    Have you found any mention of something that does not bond to this stuff like perhaps wax paper.
    It would be nice to have a removable item you could use in masking off the surfaces.

    One person in one of the links I posted above mentioned putting a thin coat of Vaseline on the pin he used to puncture the tube. If so you could use petroleum jelly or saran wrap coated with a thin layer or it as a removable mask.

  17. cdquarles says:

    Any nucleophile will do, here. Water, ammonia, amines, etc. After all, how do you get ‘carbonic acid’? The carbon dioxide dissolves in the water. When a water molecule approaches in the proper configuration and with sufficient kinetic energy, a lone pair on the oxygen of water will force the carbon to reorganize its molecular orbitals. Then one the hydrogen atoms swaps to one of the other oxygen atoms, maybe with an assist from hydrogen bonding.

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