Why does solder turn dull grey on my iron and exhibit poor wetting?

I have a relatively new soldering iron. I can't remember when this started(and I've only used the iron 5-10 times) but I stopped being able to tin the tip. When I stick soldering to it it just balls up in one spot on the iron and then after 5 or 10 seconds on the tip, the solder turns a dull gray color(rather than shiny silver).

I have used nothing out of the ordinary on it. Only a brass sponge, a wet piece of cloth, and solder tip tinner/cleaner(which I only just started trying to use).

Even with the tip tinner, the tip will stay shiny(and conductive) for about 5 seconds and then rapidly turn a dull gray color, eventually even with a few black spots.

Is there something I can do to fix this? Did I just get a lemon tip or is this all normal(note I'm sorta new to soldering still)

Also, the soldering iron is this one with the included tip

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 – Nick T Dec 10 '10 at 22:20

I have used nothing out of the ordinary on it. Only a brass sponge, a wet piece of cloth, and solder tip tinner/cleaner(which I only just started trying to use)

So you've never tinned your tip? If that's the case then that's your problem. Buy another tip, TIN it, and always make sure you tin it before storing it. NEVER store it "clean" or it will oxidize and you will have a bad tip.

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 No, I mean I've tinned it(or tried to, it's very difficult cause the solder just blobs up) before I got the tip tinner. I just used regular solder instead. – Earlz Dec 11 '10 at 0:21

Soldering iron tips should never be "clean" from everything. You must maintain a small amount of solder on them at all times to avoid oxidizing the iron plating (as in Fe iron, major component of steel, iron). After brushing excess solder and flux from the tip with a sponge, reapply a tiny bit of clean solder.

If your solder turns a dull grey, that would be due to it's oxidization, which means you're either waiting way too long or the iron is way too hot.

Tip tinner should only be used sparingly as it is fairly aggressive and will ultimately eat through the iron coating.

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+1 for dirty irons. Just need a thin layer. I had a "yo momma" joke typed up, but I wussed out. – tyblu Dec 10 '10 at 21:24
+1 for the temperature comment. I've been using a low wattage iron for so long (for IC work) that I've forgotten that if the iron is too hot it will oxidize the solder quicker also. Good call and since he's using a cheap iron that could be the OP's problem as well. @Earlz Do exactly as Leon says and buy a new temp controlled iron. He knows what he's talking about - He's a regular poster over on the parallax boards as well. – SRM Dec 11 '10 at 2:03

You get what you pay for with soldering equipment, you can't expect much for \$9.95! Get a good quality temperature-controlled iron.

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My next planned soldering iron to buy is this one: sparkfun.com/products/9450 it's butane which I think I'd like cause the cord on electric soldering iron's annoy me hugely. – Earlz Dec 10 '10 at 20:05
That's OK for simple field repairs and other jobs like heat-shrink tubing, but you should get a proper temperature-controlled iron for reliable soldering. – Leon Heller Dec 10 '10 at 20:13
@user708 Better irons have better cords. The insulation is usually silicone rubber so they don't melt from a brush with the tip, and the wires are more highly stranded so they're much more flexible. If the cords still irritate you, make sure you're working at a proper space with enough room, lighting, and other tools (3rd hands, etc). – Nick T Dec 10 '10 at 20:24
well, the butane irons apparently do have temperature control, though I would assume not as fine grained as a high price digital iron. @Nick Well that's also the thing. I don't have a lot of room for doing this. I live in a 1 bedroom apartment, so my soldering station doubles as my kitchen table. – Earlz Dec 11 '10 at 0:19
@Earlz If you eat where you solder, it's probably a good idea to use lead-free solder, or get your blood tested for lead poisoning. – Matt B. Jul 8 '11 at 5:30

Either it's oxidized, not getting hot enough, or both. Unscrew the tip and check the contact with the heater. Scrub the heck out of the tip with your brass sponge and dip it in a bit of flux. Hopefully it's not pitted.

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