It is time to talk about the King itself, the glue that has made more fingers one than any other adhesive. It is time to talk about CA glue.
A common misconception of this glue is that it is analogous to Super Glue or Krazy Glue, but these are actually brand names. There hundreds of glues that are very similar chemically, and they are all forms of a type of glue called cyanoacrylate, or CA glue.
CA glue, like many adhesives in this blog, relies on monomers and polymerization. The monomers in this case are cyanoacrylate ester, but instead of being suspended in a solvent or requiring two parts like other adhesives, this glue is activated by water or humidity in the air and can set in a very short amount of time.
Unlike epoxy (See PAS1) CA glue’s versatility comes from this very short drying time. Typically, moist bonding surfaces and a thin layer of the adhesive is most effective, as more of the monomers can react with water per volume and polymerize. This process is an exothermic process as well, producing heat that drives more glue to dry. This explains why this glue dries quickly between your fingers, as it absorbs moisture and heat from your skin to expediate the drying process, making use of the high surface area on your textured finger. This is why the bond is very stubborn to break.
There are also CA activator sprays that are sold with CA glues to speed up the setting process even more. These sprays provide the perfect conditions for the glue to absorb moisture and dry in 2-4 seconds.
This glue comes in many different consistencies to match the job, ranging from a gel-like substance to a liquid as thin as water. This makes it affective at either keeping two precarious parts together or seeping into cracks to seal them, depending on the job. However, due to this adhesives reactivity with water, it has a relatively short lifespan and should be bought as needed.
I used CA glue for wood bonding on scales too small for wood glue, or when I needed to make a quick fix on plastics. From personal experience, this glue is most effective when the bonding area has a large surface area and the glue is thinned out as much as possible. A little goes a long way! I have also used this glue to fill any small voids in glued pieces of wood, such as those mentioned in PAS 2. This adhesive was perfect, as the activator made the process much faster than using wood glue or filler, and the excess can be scraped away and seconds, leaving a clean surface.
Links:
CA Glue Explained. All Questions Answered. – Top Woodworking Advice
Cyanoacrylate or Super Glue: What It Is and How It Works – Hotmelt.com
I have worked with different types CA glue before, but I did not know that there were so many of them and why they are so versatile! I enjoyed how you introduced common misconceptions that I also believed until reading your blog post, and then refuted that argument by explaining the chemical properties that allow CA glue to dry so quickly. I find it interesting that your PAS blogs explain the chemical workings behind these everyday observations, and how you include your own experiences to support your reasoning.