Soldering Iron tips V1.00

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> On this note, has anyone ever tried tin plating the solid copper tips.  I
> have some chemical tin plate solution that I use to tin plate my prototype
> boards.  I wonder if this would last long enough to preserve the copper?
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• Quality soldering tips are made of copper to conduct the heat. They are also iron plated for durability. The iron is then tinned so as to wick the solder. Good quality iron-plated tip may last for 3-4 months of heavy daily use. Once the plating wears off, however, it soon disintegrates. The by-products of soldering are corrosive and copper stands no chance!

• Quality soldering irons are more than just a heater coil and a tip, however. It is important to maintain the tip temperature depending on what one is soldering. This is accomplished with an integral thermsistor in the tip. It senses what the tip temperature is and controls the current through the heater. This is why not only can I adjust the actual tip temperature from 400 to 850F, but the soldering station will also maintain CONSTANT temperature by sensing the tip-temperature and either lowering or increasing the current to the heater. This is how I can solder very delicate circuits and a heavier component with the same iron with almost no delay! With a standard "dumb" iron, I would have to wait a while for the small tip to heat up the larger solder blob.

• On the practical side, while some of us may have a soldering station, all of us have the standard "dumb" iron. I find it helpful to have 3 irons:
  • a tiny 15W needle tip for surface mount work
  • a general purpose 45W small tip for all-around work
  • and a 80W plug-tip monster for chassis soldering and heavy wire

  All these irons have served me well for a number of easy, simple, and do-it-yourself reasons:

  • All my irons plug into a simple box that contains a common dimmer switch. That dimmer allows me to [crudely] control the tip's temperature. A typical iron is designed in such a way as to provide constant temperature to the tip DURING normal USE. That's the key... When the iron is sitting unused but still powered, it is in OVERHEAT condition. One could call this Thermal Runaway... because the iron gets hotter and hotter because nothing is cooling it down. This is Bad(tm) and leads to shorter heater and tip life. Oxidation is encouraged by high temperatures and if you do not remember to clean off the "crud" off the tip, that stuff will cook on the tip and eat away even the best iron plating! So, the need for the dimmer should be clear to you now. I don't use it to control the actual WORKING tip temperature but to keep the iron at a lower level during standby. [*] Just mark the setting of the dial that gives you a lower temperature BUT still takes only a dozen seconds to come up to operating temperature when you turn the dial to full power and the life of your iron will increase dramatically.

  • Another way to extend life of the actual iron is by the use of common anti-sieze compound on any removable/threaded parts of the iron. This would include the tip, the hold-down screw, and any other parts that are near the heater that may have to be disassembled at a later date. Anti-sieze compound appears to be a mixture of graphite, lead particles, other grease-less lubricants, in a base of high-temperature base lubricant. The later does and will evaporate (smoke away) when the iron is in operation. What is left are the other ingredients. They not only provide lubrication but also seal the surfaces from oxygen and corrosive vapors. It's quite striking how well preserved are the parts of my 5 years old 45W iron when I need to replace the tip! All the threads work, the screws don't strip, and... heat is better conducted from the heater assembly to the tip! The only downside to this treatment is that the base lubricant will boil off during the first usage of the iron - so be ready to ventillate the room! Ask for a small tube of "Anti-Sieze Compound" in any automotive or industrial supplier. It is commonly used on exhaust/wheel bolts of valuable equipment.

  • The last component of a good soldering setup is some means of ventillating the soldering fumes. The easiest solution (but far from perfect) is a small muffin fan that sucks and disperses the vapors away from where they want to go - up your nose and into your eyes (I swear!) A much better solution is to connect enough of the common vinyl "dryer vents" to connect your workbench to the window. If possible, suspend one end of this vent above your workbench and attach the other end to a small muffin fan in the window that vents to the outside. This will keep the noise near you to the minimum and also exhaust all the vapors to the outside. However, if you live in a dorm or an apartment and can not modify the window, it is prudent to have the muffin fan blow the air through an activated-charcoal filter of some sort. If that is not available, at the very least the air should pass through some material (like common "heated-air furnace" glass-fibre filter) so as to deposit as many of the soot particles as possible. Remember, nothing beats something :-)

  [*] In fact, I measured the resistance of the potentiometer inside the dimmer that gives me good standby temperature (empirical test :-) and have added a switch that gives me "working" or "standby" control of the dimmer.

  WARNING: dimmers work on LETHAL line voltage - you should know something about electronics before attempting this modification. Also, be VERY careful to properly ground, isolate, and shield this whole circuit.

P.S. Oh, I hope you appreciate the pun in the title :-)