mr. calder in order to develop a design that was much lighter. and the final mobile only weighs 920 pounds which is much lighter than the miro tapestry that alsoangs in this space. in the late 1980s, it was actually necessary to remove the mobile from the space. girl: why did they have to take it down? richard: because it need conservation treatment. not only had dirt accumulated on the surface, so we had to clean the work, but, in addition, there are parts where the metal is moving against metal and this was actually causing some wear. the conservators had to use a special technique in oer to repair these worn areas with new metal. after that was finished, then those areas were painted so that it matched the rest of the mobile. boy: is it due to come down any time soon again? not at the moment, and hopefully, we won't have to take it back down for many years. remember, what you choose to use to make your art will determine how long it lasts. varnish, while it protects paintings, darkens over time. light affects all works of art especially works