solder spikes

[Sceadwian]

The problem isn't so much the heat but what it creates (oxides) that build up on the tip, then the solder rides up on the oxide rather than wetting the tip because it's oxidized or it could be solder impurities as well. You could nip this in the bud with plenty of flux. As long as you use neutral no wash flux or an acid based encapsulated flux with a quick wash afterwards things like this will not happen.

Once the oxides are mixed with the solder from a dirty tip (you can't always see it) that's it, that solder is done, outside of perhaps a harsher acidic flux it will never flow right again.

 

[ChrisP58]

We need to remember that heat and temperature are two different things. They are related, but much the same way that watts and volts are related.

The pilot light in my gas furnace burns at the same temperature as the main element, but produces far less heat.

With a temperature controlled iron, we can control the temperature, either in fixed steps built into the tips, or by a some linear control. We control the thermal mass of the iron by changing the geometry of the tip. The wattage of the iron dictates how fast the soldering heat is produced.

 

[Sceadwian]

Not just how fast, but how much.

This doesn't matter though, if you set a temperature controlled iron too high it will oxidize just the same. Lower temperatures, HELP, but can't prevent the problem.

 

[e44-72]

Sorry I haven't replied for a while. The solder I use is 60/40 rosin core solder with 2.2% flux, so yes it does contain flux and no I don't use any other flux on the joint when I solder. I might try using flux as well on oxidised parts of the board.

Also my iron is and antex 25W iron and itt is not tempreture controlled. Might replace the tip at some point as althought the end is tinned and clean the rest is pretty oxidised.

Thank you all for your replies

 

[RCinFLA]

Caused by heating too long and driving out all the flux. Try putting a little more fresh flux core solder into the joint and pull away quickly.