Silver solder corrosive?
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finleyville

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After completing two DIY amps both with Radio Shacks silver solder I've probably went through 5-6 solder pencil tips! Each tip very quickly develops hot/cold spots where the solder does/doesn't stick. Also, the actual conical tip wears away usually on one side leaving a creseant moon shape. And on one occasion, the tapered part of the tip totally wore away!

I have tried different pencils (Radio Shack) and wattages (25 & 30). I made sure I tinned them all properly before starting using them. I have a damp sponge ready to clean the tips before/after each solder. I even pre-tin all the connections that I can before I connect to delay the time the tip touches the components.

What the hell am I doing wrong???


Since I'm about to start my third and last DIY amp project, I would prefer not to spend more money on a more expensive pencil. Is this the only solution?
 
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tangent

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I've seen what you're talking about, and it isn't the solder, it's the tip. This is why I stopped using Radio Shack irons. Perhaps they have different models with different behaviors, because other people seem happy with RS irons. All I know is that I wasn't happy with the models I used.

What's happening is that the tip can't put up with the cold shock of being run across a sponge when hot. Eventually the tip cracks and then starts falling apart.

You don't have to spend a lot on an iron to get good quality. A local electronics distributor here in town sells $9 irons with perfectly reasonable tips. I'd give you a brand, but no doubt you won't be able to find them. Just avoid RS and find an electronics shop staffed by people with a clue. They'll carry good stuff.

I have an iron here that's still running on its original tip. I've been using it relatively heavily since about October of last year, when I first got into DIY. It saw years of light use before that. Sometimes this iron stays on all day, when I'm building amps for others.
 
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Budgie

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My rat shack irons have done the same thing. I think it is the tip material. I bought a good solder station and the problem has not reoccured, leading me to believe it is the tips of the iron, not the solder.
 
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timoteus

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Quote:

Originally posted by tangent
What's happening is that the tip can't put up with the cold shock of being run across a sponge when hot. Eventually the tip cracks and then starts falling apart.



If this is the problem you might want to try the Hakko brass wool tip cleaner instead of the sponge, it cleans the tip better than a sponge and doesn't alter the temperature of the tip. It works for me.
 
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Joobu

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Tips are to be cleaned before soldering but not after soldering. I believe this prevents the tip from oxidizing when it is not in use.
 
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JMT

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I have had the same experience with the RS irons. I went through countless tips before it dawned on me that I needed to invest more than $12 on an iron. I bought two Weller irons (25w and 35w) and have the original tips on both. Also, proper tinning of the tip is important.

Incidently, I use the 25w the majority of the time. If you would like the 35w let me know.
 
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