solder type okay?

[jojokeo]

Just found two 1lb rolls of 50%/50% tin/lead rosin core solder after some much needed cleaning around the shop. But my usual go to Kester 44 is 60%/40% tin/lead. I thought I'd ask if there's any reason to use or not use these rolls with a little more "lead in the pencil" over my normal stuff? Thanks, jojo

[PRR]

You have to get 50:50 hotter to melt, and as it cools it goes through a longer "pasty" stage before it finally turns solid. More chance of a bad joint.

If you KNOW your joint can't move/vibrate while cooling, try it.

[jojokeo]

It's the fatter size as compared to the size I normally use that's about the thickness of an E string or less. I wouldn't use but for mainly larger jobs like the lugs on pots or eyelets maybe? And save the smaller stuff for my pedals and smaller jobs? I'm wondering not so much about cold solder joints but rather if it's less or more prone to the typical bad solder joints that occur so often due from the heating expansion and contraction we see so much of??? Not sure if pic is large enough to see them from a Blue's Jr repair as an example?

[eleventeen]

OK to use if you are absolutely sure they are rosin core. PRR is exactly right, need somewhat (not much) hotter hot to melt, bigger (effectively meaning longer in time) plastic zone upon freezing. There is a slightly greater demand that you produce a sound mechanical joint.


http://www.kester.com/kester-content/uploads/2013/06/Alloy-Temperature-Chart-15Feb11.pdf


I'm not especially in agreement that heating/cooling cycles produce bad joints though I guess I could be convinced otherwise. I imagine that PC board construction might make things worse, especially those horrible PC boards in later Fenders. Those are absolutely a step backwards in PC technology. I just went through a couple of (hand soldered, turret board) Hewlett Packard pieces from the mid 50's I bought cheap and fixed. I was kind of surprised, the solder joints did not look all that great but they did not look bad in any way. Yes, they had a very dark outer appearance but they weren't cracked. I doubt they were soldered together using soldering equipment any more sophisticated than an old Ungar woodburning iron.

[drgonzonm]

+1 on checking for flux type.
+1 on the temperature warning. Assure that you use heat sinks on those leads. there is about a 30 degree difference in melting temperature.


50/50, does not have the mechanical strength, that 60/40 has, the higher the tin, the stronger the solder.