It took 7 years to replace 4,000 rusty bolts.
When Vasa was built she was held together with wrought iron bolts. When the ship was salvaged in 1961, the original bolts had rusted away and were therefore replaced by around 5,000 steel bolts. In time, the new bolts began to rust which could potentially ruin the ship. This meant that all the bolts had to be replaced.
In 2011, the Vasa museum began working with Sandvik Materials Technology to develop a brand new bolt. The bolt is made from Sandvik’s stainless steel SAF 2707 HD and has several parts. Nearly all the bolts have now been replaced and Vasa is better preserved for the future.