On Nov 10, 2023, at 16:16, keantoken via groups.io <keantoken@...> wrote:

?

[Edited Message Follows]

You don't want to use thin solder wire as you will spend unnecessary time pushing it into the joint, adding extra heat. I usually use 0.6mm to 0.8mm rosin core. The Pinecil64 soldering iron has served me well and +- 1 degree C makes a meaningful difference. You want to be able to melt the solder fast, but not so fast the flux is spitting or smokes away instantly.

A soldering iron is several times hotter than the maximum temperature you want to reach the diaphragm. Even low melting solder is hot in comparison. A true eutectic 63/37 solder has a normal melting point, but melts and solidifies instantly with complete certainty. I can't overemphasize how important this is. Uncertainty is the main thing that leads to overheating. Not being able to tell whether the solder is melted, needs more flux, whether it's solid yet, whether it needs to be redone. With a good roll of 63/37 (and many of them do not have an accurate alloy mix), soldering is very quick and decisive. You don't need to hold the iron on for any longer than it takes for both surfaces to be "wetted". The pad does not have to be completely covered in solder, you just want to look at the edge of the solder blob and see that it is joined with the pad, rather than sitting on top like a bubble, and the moment you see that you remove the iron.