Topic: how do you know if solder is rosin or acid core?

[stresssolutions]

I've got a couple 3 pieces of solder in my little soldering supply box but don't know if it is acid core or rosin core.  How do you tell?  Does it really matter?  Thanks

[coyotecowboy]

You can tell by the way it smells, acid core will have an acrid stanky smell to it and rosin core will smell like, well, rosin.  The difference is that acid core will start corrosion in your wires, its better for sweating copper fittings together.

When in doubt, I throw it out  (...got me a rock and roll band, its a free for all!!!...)