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

Question

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

Answer 1

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.

Answer 2

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

Answer 3

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.

Answer 4

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.

Answer 5

It doesn't necessarily mean your tip is too hot etc., sometimes it might well be low quality solder.

I bought two rolls of solder (a 1lb and another 1/2lb) when I'm using it I kept getting this same result: While my iron is on it it's pretty shiny but as soon as I move the iron it turns to a matte grey colour.

I ended up buying another 1lb spool 60/40 Nippon America brand and it's perfectly shiny after every joint, however this solder I end up getting is a bit too thick for my daily use at 1.2mm.

I still uses my low quality solder though because it still gives a good joint just not shiny, I uses my NA brand solder now as just a tip tinner and tin the tip with it when I putting it away, it leaves the tip with a shine when I'm done with it.

Here are some tips:

• Try not to leave the iron too long on the joint because you can damage the pad and burn away the flux resulting in a poor connection.
• Always tin your tip before, during and after soldering to prevent oxidation.

With practice you will master this skill, soldering isn't hard to do just keep on practising.

Have fun and happy soldering.