The only time I tried an extreme pull test on a set of .012s, the crimp is where they failed. I didn't pull hard enough to suit myself, so I'm using a minimum of .015s now.
I simply cannot believe that your lines failed at the crimp. This just doesent happen
For years people have posted on this and other forums that "crimped lines do not fail"
Every time that I have posted that a crimped line is a failure waiting to happen, I'm flatly told that I don't know what I'm talking about.
If I were you, and your plane flew fine with .012" lines I would stay with them BUT I would wrap the as per AMA.
What plane were you flying and how much does it weigh.
I only ask this because my Still Stuka and my sons Skyrays are powered with FP .20's. When I changed from .015 to .012" the performance increased dramatically.
Larry, Buttafucco Stunt Team