Failing adhesive

 

What's this?

  • An archaeological pot broken into many pieces had been repaired, but the repair is failing causing the pot to slump.

What’s happened?

  • The adhesive joins have failed due to the high temperature where the pot was displayed.
  • In this instance the room temperature has exceeded the glass transition temperature (Tg) of the adhesive. Tg refers to the temperature at which a substance changes from a "glassy" state (hard and brittle) to "rubbery" (elastic and flexible).
  • The adhesive has become soft and pliable and the joins have pulled apart due to the force of gravity.

Can the damage be repaired?

  • Yes. The failed adhesive canbe removed with solvent and the break edges cleaned. The pot can then be re-adhered.

What could have been done instead?

  • The pot could have been displayed out of direct sunlight and away from heat sources. An adhesive with a higher Tg could have been used.

From Renita Ryan, Artlab Australia