How Do I / Can I Solder Together Piano Wire?

Ive been trying to join Piano Wire (Tempered Steel) end to end into triangle shapes, so 3 pieces of piano wire per triangle obviously. This is for a sculpture i am trying to develop. Problem is i cant figure out a way to join these wires. I tried soldering however i cant find any form of solder or flux that will bond them (usually it just breaks or slides off when cooled). I tried welding grade epoxy and it slid right off after drying. I don't have access to welding equipment which i feel is the answer to this problem. I also cannot resort to bending the wire around itself or wrapping wire at the corners of the triangles because i need the connection to be more or less unnoticeable for various reasons. I've been wasting money on this for about 2 weeks now, does anyone have any ideas of solutions or on soldering for piano wire. Thank you!