I don't recall ever having the problem with the iron before, but it's been a few years since I used it, as I'm just getting back into some projects since my Electronics degree.
I bought some solder for a new project (I need a lot) and it's lead-free:
95% Tin
4% Silver
1% Copper
Now, I'm not sure how tolerant the values are for melting point but I can say that it does appear to act Eutectic, like the known combination 95.5/4/0.5 (Indalloy 246) which has a melting point of 217 degrees Celcius.
According to the manufacturer of my Iron (Antex) it has a tip temperature of 370 celcius.
I sanded down the tip yesterday with a fine grain metal sanding paper to see if the tip just needed cleaning, however it's now gone "black" instead of the shiny silver it was when I first sanded it.
The real question I wonder is where the problem lies, is it that my tip is dead, is my iron too low power or is it just that my iron is dead.
I ask because I need to know whether to replace the iron, the tip or a higher power iron. My preference is to stick with the Antex irons, and I prefer "precision" bits like the on in my current iron, so, what are the recommendations?
Best Answer
Your tip is dead since you have now sanded off the special coating. It will of course still get hot, but will oxidize rapidly so that solder won't wick onto it. This will make it very difficult to solder with.
You say the tip is supposed to be 370C (700F), but is that temperature controlled or just some open loop guess? 12W sounds very low for a temperature controlled soldering station, and also not enough to heat much beyond a little solder and a wire or two at the same time. For example, my Weller WES51 temperature controller soldering station has a 50W iron. Of course most of the time it's not run at 50W, but that's what the control algorithm can cause it to put out when it senses low tip temperature.
Since you just destroyed your tip (and the iron if it has a fixed tip), maybe it's time to get a real one that has temperature control.