| An adhesive is a substance that is used to fix or bond | | | | are two chemicals that are not adhesive until they are |
| two surfaces together. They come from very small | | | | mixed together; then they rapidly solidify into a |
| powered substances to incredibly strong. Adhesives | | | | chemical bond that is very difficult to separate on a |
| can be natural or synthetic but more commonly are | | | | flat surface. |
| the latter, man made glues produced for anything from | | | | Hot or 'thermoplastic' adhesives are the type often |
| household repairs to industrial bonding. | | | | found in workshops and are what many of us used in |
| The original adhesives were natural, plant resins or | | | | school. They are often loaded in a solid state into a |
| animal substances. Ancient Egyptians used animal | | | | glue gun which heats the substance, letting it run onto |
| glues and Native Americans used rendered buffalo | | | | the surface that needs it. The surface is pressed |
| hooves. Natural adhesives are usually classed together | | | | against the desired object and generally left under light |
| and are separate from synthetic ones which | | | | pressure until the glue has cooled. Upon cooling the |
| themselves come in a variety of forms. The cheapest | | | | two surfaces should be very difficult to separate. |
| and weakest are usually simple solvents that | | | | The glues used on masking tape are pressure |
| evaporate and leave a adhesive bond, basically drying | | | | sensitive and form a bond when pressed into place, |
| out, like the white glue used by younger children in | | | | but can be peeled away at a later date. They also |
| crafts that can be painted onto a surface. | | | | come in more permanent forms that are used in |
| A fairly common form of adhesive is reactive; the well | | | | safety labels and sound dampening seals among other |
| known two part epoxy comes under this group. These | | | | things. |