Chain Reaction Puzzle

Chains. Make-up. What's the connection? The answer lies in a film. The DIY chain of shops, TEXAS, once made a film about their new eye make-up. They called it "The Texas Chain Store Mascara". I digress.

Below you can see several bits of broken chain. I have been told to join up all the pieces to make a complete necklace using all twenty links.



However, it is a very fiddly job, and it takes one minute to cut one link, and two minutes to join it up again. How long will it take me to finish the necklace?