Ball-chains and age
Although I and many other firedancers consider ball-chain the best kind of chain to use, it does show signs of wear. Specifically, each ball, which is curved into a sphere from a flat piece of metal, gradually spreads apart. In theory, the rods that link the balls could eventually pull through, though I'm not aware of any incidents where this has happened.
This is a gradual process where the balls at the hot end slowly open up a little. Heat is clearly a factor--the balls at the cold end have opened up very slightly, but not as much. This suggests that you can reduce the spread by switching ends after a while.
The following pictures are of my own chains, which are nickel-plate steel, after about a year of constant use, and 200-250 burns. I almost always use lamp oil, which burns relatively cool. It is quite possible that hotter-burning fuels, like white gas, would cause a similar amount of wear after fewer burns. Then again, white gas burns are shorter, so the total time exposed to heat for the same number of burns would be lower.
Stainless chains may bear up to firedancing conditions better (or worse) than nickel-plate chains, but I don't have enough data to comment on that.
Update: 29 May 2002
Although I still think ball-chain is the best all-around type of chain to use, I have now seen one instance where the chain failed at the cold end: the rod attached the ball caged inside the connector snapped. My guess is that this connector may be under added stress if it is rocking against the wall of the connector.
In Photo 1, you can see the spreading clearly; if you look carefully, you can make out the flared end of the rod inside. Photo 2 and Photo 3 show the same section of chain next to a new section with the flared end of the rod revealed for comparison.
Copyright © 2001– Adam Rice. All rights reserved.