You may have noticed that some plants occasionally secrete a sticky substance. This resin is produced for various reasons, depending on the variety of plant. For instance, it may be used as a way to coat itself in order to seal in moisture; the resin may inhibit the growth of parasitical plants or it may trap harmful insects, preventing them from eating the plant. Well, if we noticed this sticky substance, then so must have our ancestors. Archaeologists have discovered 6,000 year old ceramic pots that had been glued together using resin secreted from plants. Although this gives us proof of the use of glue at around 4,000BC, the chances are that glue was being used by man several thousand years before this time.

Just as with modern glue, the resin would only stay in its viscous liquid form for a limited period of time. Because of this, it is likely that these ancient people either took the pieces of their pot to the plant or took part of the plant to the pot. This limited time period before the glue hardens and sets is called open time. The open time of plant resin glue would vary according to the chemical make up of the resin and the environmental conditions at the time but it would probably have been considerably longer than the open time with Super Glue (aka Krazy Glue), which can be a few seconds. In fact, putting a smashed pot back together would probably have been done in stages. Perhaps one piece was glued into position and held (or, if possible, clamped) for over an hour before it was left to completely set. The next piece may have been glued the following day, and so on.

Animals have also provided us with glue. This discovery would have probably come quite easily once we had started cooking meat. After all the nutrient parts of an animal were eaten, the remaining bones and tendons could be cooked at high temperature until a melted substance was created. In its liquid hot state this would form powerful glue. It is likely that early glue users were more interested in using it to decorate caves, skulls and bones. Eventually man would have discovered that this glue was particularly suited to sticking wood together and would have been very useful for boat building and general repairing. There is evidence, from stone carvings found in Egypt going back to the time of the Pharaohs, of furniture repairs using glue made from animals. Animal hide glue has an open time of just a few seconds, so users would have needed to heat it to a high temperature and apply it very quickly. The good thing about this kind of glue is that it can be stored. All you need to do is let it cool. When you need to use it just heat it up again.

Through the ages we have learned to mix glues with fat and other substances in order to refine its properties. Different glue mixes were made for different applications. The first glue patent in 1750 heralded the start of full scale production of glues. In the 20th century synthetic glues began to appear. The most notable breakthrough was when Dr. Harry Coover and Dr Fred Joyner discovered cyanoacrylate, which is now known as super glue (or Krazy Glue). This glue was so strong that when it bonded two parts, and a subsequent effort was made to separate the parts, the break or tear would typically not happen at the glued joint but another weak point would yield first. A derivation of cyanoacrylate was (and still is) used for sealing wounds as an alternative to stitching. This was put to good effect in the Vietnam conflict where service personnel's wounds were quickly sealed using the substance while they were in the localized battle theater. This was a quick fix prior to their hospitalization and saved many lives, according to Dr Coover.

Glues are used in a multitude of applications. Recently, synthetic glue has been made so strong that it can replace nails, allowing a seamless finish. Other uses are in pest control where glue is used to trap rodents and flying insects. The heavy duty glue used by Insectocutor Glue Boards virtually guarantees that a fly will be trapped on the board as soon as it lands there. This takes us back to where we started. Just as some plants have used glue to trap insects, so we are doing so today - and with great effect.