Cerro bend alloy for low melting point electrical solder

[Linstrum]

I have an application where using cerro bend ultra low melting point alloy would solve a lot of problems. I need a fusible link that doubles as an electrical connection that will destruct when the temperature goes above about 90°C (~190°F). Does anyone have any suggestions about using cerro bend as a soldering alloy? I need to know things like electrical conductivity so as to determine surface area of electrical contact, fluxing, surface preparation, what it will not wet, if "tinning" the surfaces to be soldered is needed first, etc. The nominal composition for cerro bend alloy is 50% bismuth, 25% lead, and 25% tin. Thanks! Linstrum

 

[JimMetalsCeramics]

Cerro compositions are used for automatic sprinkler systems (fire prevention). When the alloy gets hot enough, it melts and your overhead sprinkler turns on.

Cerro and MetalSpecialties carry these alloys. They should have data on each composition.

http://www.cerrometal.com/lowmelt.html

http://www.mcp-metspec.thomasregister.com/

http://www.canadametal.com/products/legend.htm

I have worked on electrical safety components. The only problem I see is that it may take some tricks (e. g., vertical orientation of electrodes) in ensure that the melting of the alloy ensures an electrical break in the circuit. Some fuses are designed the way you propose. An engineer at Bussmann told me that this was their biggest issue.