Soldering questions and need help.

Ferrariassassin

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I have been soldering for a few years now and have not run into much trouble but recently i have been trying to solder these wires together where a Micro USB cable was split in the middle so i stripped the 4 wires, and am solderer them 4 together. The problem is no matter what i do the solder WILL NOT stick to the wires no matter what temperature i use nor what Solder i use. I have tried 18, 20, and 21 gauge, used lead and non lead but still does not work even in the slightest. My solder tip is clean and i have tried 8 new tips and none make a difference and all have been properly tinned before use and always preheated. I have also used 3 different solder guns and heck i even checked the temp with my temp gun and all 3 are at the proper temp so it cant be them. The solder just beads up and slides around the wire as if it was water falling off a hydrophobic texture. At first i thought maybe the wire was not hot enough for the solder to stick to but i checked the temp of the wire when heated and its perfectly the right temp to melt the solder and the same as the thousands of other things i have soldered on. So maybe i am missing something and is why i am asking here if anyone knows whats up with this because i have never experienced something so solder proof that seems impossible to do. Are Micro USB's made to be impossible to solder so you are forced to buy a new one or am i missing something i do not know? Hope someone can help.
 
Solution


Flux-core solder on its own is often insufficient. Get your hands on some non-acidic solder flux that comes in a syringe. Apply the flux to the joint(s), heat the joint while the flux is present...

spankmon

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Many of the very small gauge wires have a nylon thread running through the middle of the copper strands. The smoke created when you heat that plastic thread causes the solder to be repelled. When I solder thin wires (headphones, usb cables, etc) I will first unravel the copper strands then snip off the nylon thread with small wire cutters. Sometimes, if there is just one hair of the nylon thread remaining, the solder still will not stick. Usually it is not worth the effort so I'll completely replace the cable.
 

Ferrariassassin

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Is it worth it? No it is not even worth 1% but i am the kind of person who will not give up until i learn how to fix it unless it will cost money. So if it will not cost money to fix it i will keep trying until its fixed or completely destroyed. I guess i mainly want an answer as to why this is happening than i actually want to fix it because it just blows my mind as to why its doing this.
 

Ferrariassassin

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Well it has a flux core yes and i also tries solder with no flux core. I also made a special vasume puip that sucks all the fumes up. I know FLux is bad to be breathed but it usually only hurts you if you constantly breath them in daily from what i heard because when i first started soldeing i though the smoke was from melting lead and of course lead releases no smoke at that temp so it was the flux lol. I guess as time goes we all learn mote and more.
 

Ferrariassassin

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Well these cable has 4 wires a Red, Black Green, and White. They are all a little bit thicker than a toothpick and the wire in them are many thin silver looking wires with no thread of such things in it. I really do not care if it gets fixed or not i guess i mainly just wanted to know why the wire would not solder and it confused me so i thought if i could understand to as why it is not working it would help me understand and help me on future projects :) Also thanks for telling me about the Nylon Thread thing, i have seen it mainly in headphone wires and i always wonderd why they had them, is it for strenth ot just to know which wire is which?

 


Flux-core solder on its own is often insufficient. Get your hands on some non-acidic solder flux that comes in a syringe. Apply the flux to the joint(s), heat the joint while the flux is present and then apply solder to the joint.

Fine gauge wire (24 gauge and higher) may be enamelled or coated in a very thin heat-resistant insulation. This kind of insulation is very hard to strip, not worth repairing.
 
Solution