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I finally figured out why my soldering joints kept failing after 6 months | Electronics Repairers - Guest Forum

I finally figured out why my soldering joints kept failing after 6 months

Been fixing audio gear for about 3 years now and I could not figure out why some of my repairs would come back with cold joints or cracks right at the solder point. Last week a customer brought in a vintage amp I worked on back in March and said the left channel kept cutting out. I popped it open and saw the joint looked fine but had a tiny ring around it. My buddy who does board repair for a medical device company happened to be hanging out and took one look and asked if I cleaned the pads before soldering. I told him I always use flux core solder so why bother. He just handed me a fiberglass pen and some isopropyl alcohol and made me clean a pad on a scrap board. The difference was night and day, the solder flowed way flatter and wet the pad completely. All this time I was just melting solder onto dirty pads and wondering why they failed. Has anyone else skipped cleaning and regretted it on a specific type of board?

2 comments

2 Comments

john_johnson752mo ago

Wow, hold on. You were just melting solder onto dirty pads for three years? That's wild. I've been plumbing for a long time and even we clean copper pipes before sweating them, it's just common sense. A little sandcloth or emery cloth makes a huge difference there too. Sounds like that friend saved you a ton of headaches.

jadep412mo ago

Clicked into this thread and it hit me right in the gut because honestly this applies to so much more than soldering or plumbing. I've noticed this same pattern everywhere in life where people skip the boring prep work and then wonder why everything falls apart later. Like how nobody reads the instructions before assembling furniture and then they have extra screws left over. Or how people start relationships without really talking about the hard stuff first. It's like we're all in such a rush to get to the exciting part that we forget the foundation is what actually makes things work. Your friend gave you a gift by showing you that the tedious bits matter just as much.