Finally figured out why my solder joints kept cracking

Been doing avionics bench work for about 4 years and kept getting hairline cracks on wire splices. Last week a senior tech watched me for 2 minutes and pointed out I wasn't letting the joint cool naturally - was blowing on it like a candle. Anyone else pick up bad habits early that took way too long to break?

2 comments

2 Comments

noahcampbell1d ago

The cooling trick is real but have you considered that your iron tip might be running too hot too many people crank it up to get faster work done and the thermal shock when you blow on it just makes it worse we learned in the factory that letting the joint cool at room temp with a tiny bit of movement actually relieves stress same goes for your tinning method a thick layer of solder traps heat longer.

karenw901d ago

Oh man, yeah I went through the exact same thing with my old Weller station. I used to crank it to 400C thinking I was being efficient, but the joints were always cold and brittle. I finally backed it down to around 350C and let the tip sit on the pad for a good three seconds before feeding solder. Now my joints come out all shiny and smooth, no stress cracks. And you're spot on about the thick solder layer too - I noticed after I started wiping the tip clean and using just enough to flow around the pin, the whole process got way more consistent. It's like the iron has to work less hard and the joint cools naturally.