A short time ago world silver market prices reached levels not seen since the 1980’s. While prices have abated somewhat, they remain plateaued above $30.00 per troy ounce. The price of silver containing brazing filler metals reflect the high price at which silver is traded around the world.
A common braze filler metal for copper is the 15% silver – Stay Silv 15. This alloy has a long history as a reliable choice for many copper applications, primarily copper tube connections. Many people equate the amount of silver with joint strength, (an often erroneous conclusion). Based on this braze operators and specifying engineers are reluctant to change to a lower silver content product. Compounding this is the issue of adjusting to different melting characteristics inherent associated with a new braze composition.
For replacing the 15% silver alloys a smart choice is Harris Dynaflow. This alloy contains considerably less silver, effectively reducing product cost about 50%. Dynaflow was formulated to mirror the melting and flow characteristics of Stay Silv 15. This means operators don’t have to spend time adjusting heating and timing to accommodate the new braze rod.
Dynaflow has been used in thousands of connections for over 25 years – a testament to its strength. As confirmation we partnered with the Edison Welding Institute (EWI) to conduct a series of fatigue tests; Dynaflow and Stay Silv 15 at both room temperature and 300°F. You can see the results in the attached whitepaper. In all tests failure was in the copper tube – not brazed joints made with either alloy.
Conclusion: For a correctly made copper tube braze connection Dynaflow offers equivalent joint strength at a dramatically lower cost.