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Did I ruin my volume wheel while soldering? Answered

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I just started out soldering wires and audio plugs, ambitious to do more interesting things later on, but first things first.

I was busy fixing this handy volume controller for 3.5 jacks(for the second time, first time a few months ago was succesful and it took some time before it started crackling). It has a small PCB with three holes for the left, gnd and right wires.

Now the holes are a bit brownish around the edges and I can't get the solder to stick to the circuit without it "popping off" with the cable after half an hour.

Can anyone help me out?

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jeff-oBest Answer (author)2010-08-19

Does the brown stuff flake off? That's flux. Clean it off with 99% alcohol if you can. Can you tell if the copper pads have lifted off the board? If they have, you may be screwed. If not, try soldering again with the proper solder (60/40 or 63/37).

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cephalopoid (author)jeff-o2010-08-20

I went to the electronics store with it, and they gave me some directions. The matter has been circumvented by using rigid/thick wire and scraping a bit of paint off the copper with the back of a stanley knife, soldering the thick wire on that contact after having it in place through the hole, and voila, I had three connectors. The only real disadvantage is that when you've soldered the first end and begin on the second, the solder of the other end melts as well. But I managed.

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NachoMahma (author)2010-08-17

. It's sounds to me as if you are getting cold solder joints due to your iron not being hot enough.

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cephalopoid (author)NachoMahma2010-08-18

It's a 30 watt iron! But yes, the joints are way bad. I can barely get the wire hot enough for it to melt the solder. Is my circuit connection broken, though? Can I fix it by removing the brownish stuff somehow? Scrape off the burn and still use it?

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NachoMahma (author)cephalopoid2010-08-18

.  I'd try using some fine sandpaper (or similar) before I'd try scraping,but, yes, you need to remove most of the "brownish stuff."
.  As frollard mentions, you really need some kind of flux. For electrical soldering, rosin core works very well.
.  Clean the tip of your iron, also. Google is your friend.

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cephalopoid (author)NachoMahma2010-08-18

I tried googling, but I couldn't find any pictures comparing burnt circuit boards connections and just dirt. I'll try wiping it off and listen to frollard and look for the right kind of solder. The solder I use is from a random hardware store. I bought it a few years ago. It's 50/50 Tin and Lead. Its flux is named S-39 copper, if that makes sense. Says here it's good for gas and water conduits, as well as copper tubes in general. Maybe that's why it melts so difficultly. I should have used my sound mind and looked at what type of solder I needed instead of just taking what I had lying around. I still wonder how I've managed to fix it last winter, though.

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steveastrouk (author)cephalopoid2010-08-18

50/50 is NOT what you want for circuit boards, as Nacho says. it may even be acid cored. Electronic solders are usually 60/40, with a rosin core.

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NachoMahma (author)cephalopoid2010-08-18

.  That sounds like an acid core solder - NOT what you want to use on electronics as it eats everything up after a while (eg, "brownish stuff").

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frollard (author)cephalopoid2010-08-18

Are you using rosin core solder? Flux is the most important part of soldering.

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