Instead of tying a knot with wire line, try a leader sleeve. American Fishing Wire's Leeder Sleeve is made of brass with a black oxidized finish. Sleeves can be fitted to wire, monofilament, and other various lines. Burr-free nonabrasive finish combined with high strength and corrosion resistance makes AFW's sleeves the preferred choice of professional leader, lure, and tackle manufacturers.
These sleeves are just what I've been looking for to make ice-fishing leaders, easy to position and crimp.