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Preliminary Assumptions:

  • Metal hardness matters: I am assuming metal hardness matters when it comes to cleaning soldering tips with metal wool.
  • Chrome tip quality and material: I am assuming (good quality) soldering tips are chrome plated/electroplated.

Main Details:

So, for cleaning soldering tips:

  • [metal hardness(soldering tip)] > [metal hardness[metal wool)];

    I.e., the hardness of the soldering tip must be greater than the hardness of the metal wool.

Now, for metal wool, traditionally, brass wool is used. However, copper wool does exist.

So, essentially:

For [metal wool(x)], x = brass, copper, etc.

My particular case and example:

On sponge wool available: I am using copper wool. In this example, I'd like to consider copper hardness. (This copper wool might be copper-coated steel-strand-cored wool). Does copper wool work effectively to remove oxidation from a soldering tip.

On the black oxidation: Being more a technical hobbyist than an experience technician, I've used and abused my soldering iron tip in that I've used it for other projects, like makeshift plastic welding. This did not come without consequence. That consequence was the heavy, burnt, carbon-containing material and debris collected on the surface of the shaft and tip of the soldering iron, with black oxidation on the tip. However, other than that, I've had very little use with the soldering iron and have treated it pretty well--no plating has eroded so the areas that have been cleaned are wettable with solder.

One more detail: clarification on intent of question: This is not a question of a non-traditional sponge is better; rather, if a brass sponge is safely interchangable/fungible with another type of sponge. Hence the angle of my answer below.

Thanks!

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  • $\begingroup$ As you mention, the plating (and surface properties in general) are essential to a well functioning tip. If it is irreparably ruined, IMO that's the time for abrasives. A tip cleaned that way and without plating won't last long but still will be better than nothing at all. Better to care for the tip (i.e. don't overheat, at least not for long, and avoid corrosives) $\endgroup$
    – Pete W
    Commented Feb 13 at 0:49
  • $\begingroup$ PS- I've had no issues with damp sponges, my feeling tip lifetime is more a matter of working temperature $\endgroup$
    – Pete W
    Commented Feb 13 at 1:27
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    $\begingroup$ @PeteW, Mr. Pete, I edited my question to make it more clear. My main focus was a comparison between wools and their practical use in place of brass wool (due to cost constraints). $\endgroup$
    – Prashanth C
    Commented Feb 13 at 2:26
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    $\begingroup$ I included some notes on cleaning soldering iron tips which you might find useful in this answer. $\endgroup$
    – Andrew Morton
    Commented Feb 13 at 18:35
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    $\begingroup$ Thanks, Mr. Morton. :) Good refresher for anyone who's not doing this everyday. $\endgroup$
    – Prashanth C
    Commented Feb 14 at 13:33

4 Answers 4

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Zinc, which forms a non-reactive surface on brass, is almost insoluble in solder. Copper is soluble in solder, and forms inter-metallics in solder. It's also softer and weaker than brass, which makes threads more likely to break off and adhere to the iron and be transferred to the work.

Although it is in the range of hardness and softness suitable for wiping a soldering iron, there is no reason the think it would be better than brass, and some reason to fear that it might be worse.

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  • $\begingroup$ Thank you for your answer and good point on the brass alloy chemical composition. The utility of brass is its ability to traditionally resist oxidation at environmental conditrions (say RT). That said, this question was not meant to inquire whether one was better than the other. It was more a question of substitution/fungibility due to access and costs (I got a copper wool sponge for cheap and available). $\endgroup$
    – Prashanth C
    Commented Feb 13 at 18:56
  • $\begingroup$ Please see edited details for clarification. Thank you, Mr. David. $\endgroup$
    – Prashanth C
    Commented Feb 13 at 19:04
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Is this for saving a tip? Or for regular use? In either case, you shouldn't ever need to abrade oxidation away.

For regular use you just tin the tip and dip the heated tip into a pile of brass wool and pull out. Most of the time the solder already on the tip from using it is enough that you don't need to tin it. Hardness is irrelevant here since the solder is molten.

To actually save a badly oxidized tip, you can keep feeding flux cored solder and wiping it off as previously mentioned until it gets clean but what you're really after when you do this is adding flux in the solder to the tip.

Therefore, in the worst cases you you directly add liquid flux to the tip or let the tip sit in a puddle of liquid flux for a bit then wipe it off in the brass wool. Repeat as necessary until the tip is clean. Then tin the tip and wipe it off one last time in the brass wool.

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  • $\begingroup$ Thank you for your input, Mr. DK. Very practical advice. You are right about the strategy to use rosen-core solder to re-tin a tip in the case there is exposed relatively unoxidized surface of the tip to tin. $\endgroup$
    – Prashanth C
    Commented Feb 13 at 2:19
  • $\begingroup$ I guess this would be saving a tip that has been badly oxidized using copper wool. My question is asked because, theoretically, if you a metal wool with a higher hardness, you would risk damaging your soldering tip. This is probably deep into the materials engineering of this. Thanks again. :) $\endgroup$
    – Prashanth C
    Commented Feb 13 at 2:23
  • $\begingroup$ @PrashanthC Like Pete said, only abrade oxidation if you're going to lose the tip anyways. Otherwise feed it lots of flux. It will eventually come off. Even if the tip is covered in melted plastic you should try to wipe as much as you can while hot and only abrade to remove the surface plastic before wiping while hot to remove the remainder of the plastic. Only ever abrade down to the metal if you expect to lose the tip anyways. $\endgroup$
    – DKNguyen
    Commented Feb 13 at 2:26
  • $\begingroup$ @PrashanthC Now, if you're trying to clean up off an aluminum, brass, or bronze workpiece then you use copper or brass wool. Even brass wool can be hard enough to take material off aluminum or brass but you will take off less material than steel wool. Usually you don't need to be so worried about excess material loss that you can even use Scotch Brite which contains aluminum oxide. But the thing about soldering iron tips is that they are solid copper with a thin iron plating covered in thin nickel and these thin layers are too easy to remove by abrading and you basically destroy the tip. $\endgroup$
    – DKNguyen
    Commented Feb 13 at 2:30
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    $\begingroup$ @Prashanth -- Upon further reading, I think the emphasis on flux in this answer is the key. It also explains why at high temperatures the same amount of applying flux-bearing solder and wiping, feels like it stops working vs oxidation. Not only is the rate of oxidation higher, but the life of the flux gets shorter with higher temp. $\endgroup$
    – Pete W
    Commented Feb 13 at 22:12
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high-quality soldering iron tips are plated with iron, not chrome. Chrome is not wetted by solder. Iron is well-wetted by liquid solder and impervious to corrosion from the fluxes used in solder.

Black oxide buildup when soldering is an indication that you have pierced the iron and the copper underneath is being actively eaten away by the flux. The soldering iron tip is then worn out and must be replaced.

Abrading or filing a soldering iron tip destroys the iron plating and should never be done. The wet sponge method is best and will not harm the iron. If you are wearing heavy denim jeans you can clean the tip after the wet sponge by rapidly flicking the tip back and forth across your thigh. This is known as the "Chemelex Wipe" by its practitioners in the 1970's.

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  • $\begingroup$ This is a good position; however, I believe another user guessed correctly that the heavy oxidation is actually from burned plastic residue. Hence, the need for a little mechanical abrasion ontop of flux. Thank you for your response. $\endgroup$
    – Prashanth C
    Commented Feb 13 at 18:58
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Answer

Prelude Outside of tin-cleaner for heavily oxidized and burned-carbon-deposit-containing tips, in theory, there should not be a problem with using copper wool or copper-coated steel wool in place of traditional brass wool.

Briefly, a combination of tin cleaner plus abrasion may be useful depending on your circumstance. One Caveat: When using abrading materials (abrasives), the major concern is to not damage any plating of more expensive and/or high-quality soldering iron tips.

With that said, now, to directly answer the question, we will consider abrading materials below:

Please see background and explanation below.

Background: First, let us consider the physico-chemical properties:

Metal Hardness Qualitative Comparisons:

  • Chrome is harder than copper. (significantly harder).
  • Chrome is harder than brass.
  • Brass is harder than copper.

Quantitative hardness values:

  • Hardness (chrome) = 8.5 (source: google)
  • Hardness (brass) = 3 (source: google)
  • Hardness (copper) = 3 (source: google)
  • Hardness (low-carbon steel, of steel-strand-cored metal wool) = 3 (source: google)

Explanation: So long as the metal hardness of the wool or metal bristled brush that you are using is softer than the tip, you don't risk scratching it. This matters when considering heavy oxidation build up and burned carbon-containing residue.

With cleaning, a traditional explanation is that water sponges can cause thermal shock and cause cracking or damage of soldering tip--I am unsure if this is a fair comment to say because room temperature water and room temperature brass wool only differ in terms of heat capacity differences. The advantage to brass over water, then, may be more of a mechanical physical abrading. This is why we may opt for brass wool normally. With that said, based on the above physicochemical properties, copper-coated metal wool is fungible/comparable to brass in hardness, and thus in use. And, even if the copper peels off, the soft steel is not hard enough to scratch the soldering tips (if the above assumptions and property values are correct).

Thus, there should not be any issues with using copper wool over brass wool, even if the copper coating is somehow removed.

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  • $\begingroup$ You shouldn't ever need to abrade a solder tip to remove oxidation to be honest. To remove melted plastic maybe. $\endgroup$
    – DKNguyen
    Commented Feb 13 at 0:04
  • $\begingroup$ I like this point. I know some very practical technicians train or say they use wire brushed to remove bad oxidation--but that it kills there soldering irons. Perhaps, they work at infinite budget labs! :) $\endgroup$
    – Prashanth C
    Commented Feb 13 at 2:28

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