I'm in the process of building a Mid Production Barrel Travel Lock for my tank. I have the mounts (A) and the arms (B) (Lower Picture) complete and I'm heating some water up to form the styrene cradle portion for the barrel. My question is and I think a collective group might aid me with this, What can I use to represent the chain that would clamp the barrel down?
Here is what I'm doing.


Thanks and Merry Christmas!!
Derek