Soldering Iron tip - black residue - Page 1
Forum section: electronics / beginners

author: pigtwo
author_rank: Regular Contributor
timestamp: July 15, 2017, 10:26:37 pm
content: Hello everyone,I'm soldering a board and I'm running into a problem with my soldering iron. There is a black film(residue) developing on the tip and solder will not stick to this(see attached picture). It's making it very hard to solder as I have to scrub it with the brass pad thing about every 30 seconds and it doesn't even remove all of it. I'm not sure why this is happening as I've used this soldering iron probably about 8 hours before this and I haven't seen this yet.I've seen some stuff online saying to wipe it off on a wet sponge but that doesn't work for me. I have the temp at 400c with 63sn/37pb solder. The soldering station is a Hakko FX888D-23BY.Does anyone know why this is happening and how to clean the tip?Thank you!

author: IanB
author_rank: Super Contributor
timestamp: July 15, 2017, 10:35:36 pm
content: Quote from: pigtwo on July 15, 2017, 10:26:37 pmThis has happened to me once when I was experimenting with soldering aluminium. Contamination from what I was soldering ruined the tip in the way you described and made it very difficult to recover. So I wonder what you are soldering? Is it clean and free from contamination, and is it copper, tin or iron?Also, I hope a temperature of 750°C is a typo! For tin/lead solder I usually find 350°C / 650°F works fine. If you have the iron too hot it will burn the flux which is not good.Lastly, try not to "scrub" the tip as you can damage the protective plating. Usually a gentle wipe is all that is required, and keep it well covered in solder at all times. You should just be wiping off the oxidized liquid solder, not actually cleaning the tip.

author: IanB
author_rank: Super Contributor
timestamp: July 15, 2017, 10:36:49 pm
content: One last thought might be about the quality of the solder and the flux core. Not all solder is equal, and poor solder might lead to poor results.(And if you really need to clean the tip, get a tin of tip cleaning/tinning compound.)

author: pigtwo
author_rank: Regular Contributor
timestamp: July 15, 2017, 10:51:21 pm
content: Yeah 750c was wrong. For some reason I assumed the displayed temp was in C but then I realized that was way to high. The real temp was 400c. Maybe I'll bring this down to 350c.I'm soldering a basic circuit board. ENIG coated copper I believe. Your comment about scrubbing the tip too hard may be my issue. Once I started seeing the problem I started rubbing it really hard trying to scrape it off. So maybe that was my issue.I'm using 0.3mm solder with 1.2% flux. Is this good enough? Does anyone have a recommendation for a high quality solder?Thanks!

author: stj
author_rank: Super Contributor
timestamp: July 15, 2017, 10:58:15 pm
content: your burning flux,350 is good for lead-free,for eutectic stuff like yours you should really only be using 300 - maybe less.soldering is a balancing act, you want enough heat to melt the solder, but not so much that the flux burns.btw, what brand/series solder is it you have?

author: pigtwo
author_rank: Regular Contributor
timestamp: July 15, 2017, 11:05:27 pm
content: Ok thanks for the advice, I'll turn it down to 300. I almost turned it up because I couldn't get solder to wick to solder wick but I think it's because the film or whatever was decreasing the thermal conductivity.I was using Koocu 0.3mm 63/37. But I know nothing about solder brands so I have no idea if it's bad or not. I also have Jinliyang 0.5mm 63/37. I haven't used this one much because I was soldering 0.5mm pitch QFPs so I wanted slightly smaller.

author: pigtwo
author_rank: Regular Contributor
timestamp: July 15, 2017, 11:06:56 pm
content: Also, do you think the tip is salvageable? I don't really mind buying a new one it just sucks to have to wait for the new one arrive.

author: MosherIV
author_rank: Super Contributor
timestamp: July 15, 2017, 11:21:44 pm
content: HiIt is natural that some flux will collect on the tip. Just use a damp spong and wipe the tip across the spong every 2/3 joints to clean the flux off.Is the tio salvagable ?Just try it, try and tin it.Get some tip tinner. It is expensive for what it is but it brings a tip back to life.

author: forrestc
author_rank: Unknown
timestamp: July 15, 2017, 11:29:13 pm
content: Quote from: pigtwo on July 15, 2017, 11:05:27 pmToo high of a temperature will definitely cause the symptoms you are seeing, or at least similar symptoms.

author: pigtwo
author_rank: Regular Contributor
timestamp: July 16, 2017, 12:15:41 am
content: Well I'm glad I know why. This actually makes sense because I have a very nice soldering station at work but it's fixed temp and I've never had this problem with it. I think the tip is done. I can't tin it except for this one spot that isn't black. And I can't remove the black stuff at least without using sand paper or something.Thanks for all the help!

author: Ian.M
author_rank: Super Contributor
timestamp: July 16, 2017, 12:32:03 am
content: The black stuff is probably a combination of carbonised flux residue and black iron oxide from oxidisation of the tip plating. With the bit cold and removed from the iron, you *may* be able to salvage it with a fiberglass pencil to abrade away the oxide layer, followed by retinning with tip tinner/cleaner but if too much of the plating thicness has oxidised, that will expose bare copper and the bit will then rapidly erode. To minimise future problems, especially at higher temperatures, make sure the bit is cleaned and re-tinned with ordinary solder, leaving solder on it, if its going to be longer than a minute or two before the next joint, then wipe immediately before use.N.B. tip tinner/cleaner is too aggressive for regular tip tinning - don't use it unless you are having difficulty getting ordinary solder to take, and when you use it, wipe off the residue and re-tin with ordinary solder as soon as possible, certainly before touching a PCB with that bit!

author: pigtwo
author_rank: Regular Contributor
timestamp: July 16, 2017, 01:15:37 am
content: Ah ok, I don't think I fully understood the purpose of tinning until now. The basic idea is you don't want the tip to hot and exposed to air for very long.I'm probably just going to buy a new tip. They're luckily not very expensive.

author: IanB
author_rank: Super Contributor
timestamp: July 16, 2017, 01:23:53 am
content: Quote from: pigtwo on July 16, 2017, 01:15:37 amYes, and in particular if you keep the tip thoroughly coated with solder all the time then it is the solder that oxidizes rather than the surface of the bit. By doing this you should be able to wipe off the old solder and get a clean, shiny surface each time you need to make a new joint.FYI, I run my FX888 at 350°C without any trouble. Also I turn off the iron if I have a pause between joints. It only takes 30 seconds to warm up again, so this is no trouble at all and it helps keep the tip clean.

author: Brumby
author_rank: Unknown
timestamp: July 16, 2017, 03:09:15 am
content: I run my iron at amaximumof 350ºC. Generally it's 330ºC or less, but sometimes when I'm on a roll, I might nudge it up to maintain the heat when doing multiple joints in quick succession.I have also stepped away from using the wet sponge. I now use a cheap metal scourer (well, half of one) from the local $2 shop which works a treat. A fresh drop of solder, a couple of jabs and it looks like a new tip every time - cleaning all sides of the tip at the same time. No more rolling the iron in multiple swipes down a sizzling sponge.I made this move when the topic of the "wet sponge" highlighted issues of thermal shock to the tip, as well as the loss of heat. I've never felt happier.

author: Ian.M
author_rank: Super Contributor
timestamp: July 16, 2017, 03:28:46 am
content: The sponge should be damp rather than wet, i.e. wet enough for it not to char, but not so wet it significantly quenches the bit. Brass turning panscourer or brass wool (*NEVER* stainless panscourer) are supposed to be kinder to the bit but IMHO are less effective at removing the last traces of corrosive residue from more aggressive fluxes (but more effective at removing heavy residue). If you do choose to use the traditional sponge, it should be an undyed cellulose one, and needs to be washed thoroughly before first use to remove plasticisers then washed regularly to prevent buildup of contaminates. Squeeze out as much moisture as possible before use, and if its still too wet, repeat on a pad of kitchen paper.

author: Tom10000
author_rank: Contributor
timestamp: July 16, 2017, 04:02:12 am
content: if its been burning flux than get really fine sandpaper and sand it a tiny bit down until the it is not that black and go out and buy some tip tinner from your local electronics store use that on it regularly.

author: KL27x
author_rank: Super Contributor
timestamp: July 16, 2017, 07:17:25 am
content: If brass wool, flux, and tinning/solder don't restore the tip, ^+1 you can use sandpaper. Or what I would prefer is a fine stone file.But you have to be careful. There's a line between the end of the tip which carries tin, and farther up where it won't. The reason it won't hold tin away from the tip is due to a chrome plating. (The chrome plating also protects the untinnable area from oxidizing; to protect the tinned area of the tip, you try to keep it coated with solder as much as possible). This chrome plating is very thin. If you are going to use gentle abrasion or perhaps a stronger acid to remove oxides from the tip, be sure to stay away from the chrome.Underneath the chrome is a thin layer of nickel to bond the chrome. And under that is a thick layer of cast iron which covers the entire tip. This is what carries the tin and protects the copper core. In hakko tips, this layer is quite thick. There is no reason to chuck your tip without giving it a second chance. There's a decent chance it will work for many more years.The temp is adjustable so that you can use the lowest temp that works well for a given task. Sometimes you gotta turn it up, and sometimes you can turn it down. I do 95% of my soldering with my 888 between 315 and 335C. But anything up to about 350 is much easier on the tip than 400. Somewhere in that area between 350 and 400 is where tips go to heaven. And lead-free soldering equipment manufacturers rejoice. Below that, you will have to work pretty hard to wear out a hakko tip, although the pointed tips are the ones that wear out the fastest due to having very thin conduit to transfer heat to the tip, so you have to run them hotter, and because the solder tends to pull back and bead away from the very end, making it harder to keep them protected.

author: kalel
author_rank: Frequent Contributor
timestamp: July 16, 2017, 08:03:32 am
content: Quote from: IanB on July 16, 2017, 01:23:53 amYes, this seems to make a lot of difference. Even my cheap $1 or less tips seem to last a lot longer than before, by following this technique. That is, applying some solder on the soldering iron after use (usually just after unplugging). During soldering I frequently use the sponge (a sponge, something wet), as it didn't cause any oxidation or other issues yet. Then again I'm neither good at soldering or use good tools - but this does make a big difference regarding longevity of the tips.

author: KL27x
author_rank: Super Contributor
timestamp: July 16, 2017, 09:06:30 am
content: QuoteIf tip life is a concern for you, you might want to give C (bevel) or CF (bevel tip, tinned face, only) tips a try. Because the working part of the tip is a disc-shaped surface facing down, any solder you put on it tend to spread over the entire face and to stay there. As you solder, the bead stays on the face. Whenever you touch the tip to rosin/flux, flux tends to drip to the bottom, where the face and the bead are. When the iron is in the stand, the bead stays on the face. When I'm debugging/troubleshooting, I might leave my iron on for 6 hours straight, making only a few connections in that time. I have zero concern for the tip oxidizing. Even when doing a straight forward build or batch assembly, I often just walk away for a break and come back... whenever. 5 minutes. An hour. It doesn't matter. I have used the same Hakko T18 tips for many years and many, many hours. I have only worn out 1, and it was a fine pointy tip I left at 400C overnight.

author: Electro Detective
author_rank: Super Contributor
timestamp: July 16, 2017, 09:43:11 am
content: FWIW, this is my go to Youtube video to get a crusty overbaked soldering iron to perform betterHats off to the gent as he explains it in a no brainer fashionyoutube.com/watch?v=7PWmMxjXwYEThere are other vids worth watching in that URL too on the right side selection menuGood luck

author: Ian.M
author_rank: Super Contributor
timestamp: July 16, 2017, 11:09:16 am
content: Hmmm. I wouldn''t really recommend that video. A new soldering iron bit should tin easily, AS LONG AS YOU APPLY SOLDER IMMEDIATELY, but you have to rub the end of the solder into the bit surface so the flux cores melt with the solder, and keep the temperature down to just above the solder melting point. so for non-temperature contrplled irons, as soon as the solder starts to take, switch off, and carry on applying solder till it becomes more difficult to melt then switch back on, continuing till all the active tip surface has been tinned. Wrapping the solder round the bit like that video DOES NOT WORK WELL - there is no flux on the outside of the solder so as it first melts it oxidises and then its no longer being pressed against the bit and most of it just drops off without taking. If you want to try wrapping the bit in solder, you'd need to add extra flux then wrap it in a little aluminum foil to hold the solder against the bit even after it's melted.Acid flux is evil stuff - Apart from the toxic fumes, it usually has acid Zinc Chloride as the active ingredient, which (+ added moisture) is corrosive to iron and steel parts of the iron, so if you use it for tip tinning, after tinning, you should ideally remove the tip and wash it thoroughly in boiling water to remove any residual acid. Ammonium Chloride flux is a little less evil, but its residue should still be cleaned off properly.Tip tinner/cleaner - a compressed cake of Ammonium Chloride mixed with finely divided solder particles is much easier to use for tinning. Simply scrub the ckeaned bit surface across the face of the cake - don't dig it in as that just breaks up the cake, and causes the solder powder to form big blobs of solder that are less effective. You will probably still need extra solder, but the tip tinner/cleaner does most of the work for you.Also, if a plated bit is FUBARed, its often salvageable as a plain copper bit by grinding back the plating and reshaping it as needed. Plain copper bits don't last well, especially at higher temperatures, (as, with every joint, some copper from the tip dissolves in the solder unless it already contains around 2-3% copper) but you should be able to get enough extra life out of it to tide you over while you order and wait for the spare bit you should have had in stock. Bits are wear items - order a new one as soon as you put your spare into service.Using sheet abrasives like sandpaper really doesn't work that well - there's a tendency for the edges of the bit to get more abraded, breaking through the iron plating, and ruining the bit. Also they don't stand up to a hot bit so its difficult to spot clean an area that wont tin. A fine grained oilstone can be used *extremely* gently, but I recommended a fiberglass abrasive brush, because its harder to damage the plating with one. Steel wool can be used on badly oxidised bits if you have nothing better, but as it may be harder than the iron plating shouldn't be used for regular bit cleaning as you are working. You also shouldn't need it for tinning a new bit - if you do it means you screwed up and let it oxidise before you applied flux and solder.

author: macboy
author_rank: Super Contributor
timestamp: July 16, 2017, 09:25:31 pm
content: My two cents:The Iron is to hot. 300 c is fine for leaded solder. The black stuff is oxidized solder and or iron from the tip plating. Once this happens I find that the best cure is to use a tin of tip cleaner (mine is Archer brand from radio Shack, ancient but effective). After cleaning in tip cleaner, wipe on a damp (NOT wet) sponge, then thoroughly cover in solder, to the point where it is dripping off the tip. Add more fresh solder every ten seconds for about a minute. Let the tip bake like this for several minutes, adding lots of fresh solder every minute or so. After this baking process, bump the solder blob off of the tip then wipe on the damp sponge. You should be good to go now. If well cared for (no overheating, always tinned when idle), you shouldn't need to repeat this fix.

author: KL27x
author_rank: Super Contributor
timestamp: July 16, 2017, 09:43:49 pm
content: QuoteI have felt pretty sure that the tip is cast iron or some other form of high carbon iron, all of which are harder than steel wool.The coarseness of the wool is also a large factor. For removing rust on blued steel, for instance, you can use 0000 steel wool with care, but 00 wool will remove the finish before it removes the rust.I have put this to the test recently, having added a very coarse stainless steel wool cleaner to a new iron holder I made. So far, so good. The stiffness of the coarse wool gives it a lot of bite. If this is to cause a problem, I should know in a few months.So far, I don't see any problem under the microscope.Regarding plumber's flux, I think is probably not that bad. At one point, I used it fairly frequently. At that time, I only used the one pointy tip for everything, on my old velleman station. I only wore out one tip (and one handpiece) over probably 4-5 years. The flux induced rust in soldered iron/steel like mad, but perhaps due to the solder that ordinarily coats a tip, or to the specific kind of iron in the tip, the halides did not cause the soldering iron any great problem. Well, on second thought, it might be an addictive thing, where it is strong enough to clean off the oxides it creates, as long as you occasionally use it. But it you stop using it, the iron might stop wetting.

author: MosherIV
author_rank: Super Contributor
timestamp: July 16, 2017, 10:59:41 pm
content: QuoteNo, most soldering iron bits are copper core with nickle and iron plating :https://en.wikipedia.org/wiki/Soldering_iron(see the section on tips)QuoteQuoteIs that not a clue that plumber's flux is no good for electronics work?!?Cannot imagine what it is doing to soldered up circuits

author: KL27x
author_rank: Super Contributor
timestamp: July 16, 2017, 11:33:43 pm
content: QuoteIf you wash off the conductive, hygroscopic, water soluble residue, probably same thing it does to copper water pipes. A good job.It's the halides that do a number on iron/steel. They imbed in the metal and induce rust. They can't be washed off with water. This does not appear to affect copper, tin, or lead.QuoteIron plating does not necessarily mean pure elemental iron. Pure iron has very little use. The amount we produce and use amounts to squadoosh. Whereas we use a high volume of high carbon irons, such as cast, white, grey, and other types. High carbon iron can be plated hard as woodpecker lips over engine cylinder heads and whatnot. It has high rust resistance at high temp. And solder will wet to it. Elemental iron pretty much sucks in these qualities. And I don't think Hakko tips are plated in nickel at the working end. The nickel is just to adhere the chrome plating where solder is not supposed to stick. Some irons may use nickel. But I don't suspect it provides much benefit and/or it doesn't last long, else more tips would use it.

author: MosherIV
author_rank: Super Contributor
timestamp: July 16, 2017, 11:46:33 pm
content: QuoteThat is correct. The nickle plating is just there to allow other metals to adhere to it, since it is virtualy impossible to get iron to directly adhere/plate to copper.Yes, I am aware that the tip is iron plated and chrome is used further up the tip to stop it oxidizing.The point is, as far as I aware, there are NO solid iron soldering tips - they are all copper with iron plating.I do not have a problem with using damp sponges to clean tips, I actually think they are better at cleaning the flux residue off than the wire wool stuff. I do not think there is a problem with thermal shock with damp sponges, I think this was a marketing ploy to get people to buy the new thing in town at the time - brass wire wool tip cleaners.I have been told to NEVER use steel wool, only brass. I am not actually a fan of these types of tip cleaners. I think they are too abrasive.

author: KL27x
author_rank: Super Contributor
timestamp: July 16, 2017, 11:52:07 pm
content: Who ever suggested that soldering irons were made of solid iron? Read my post again. I'm differentiating between elementally pure iron and high carbon types of iron. Which are harder than brass and even steel wool.I like the brass wool. When I finally wear out a tip, I'll reevaluate. I am going on 3+ years with my current favorite hakko tips. The cost per tip so far is $3.00 a year and dropping, so I think it is going to work out.

author: MosherIV
author_rank: Super Contributor
timestamp: July 16, 2017, 11:58:05 pm
content: QuoteYou saidQuoteSaying the tip is 'cast iron' implies that the whole tip is iron and has been cast.The clue is in the name - 'cast iron'Casting iron is a process.You cannot plate cast iron onto something.You can plat the same grade of iron as cast iron. This is where we have a dissagrement in the language used.

author: KL27x
author_rank: Super Contributor
timestamp: July 17, 2017, 12:05:54 am
content: Cast iron is a type of iron. It does not mean that the iron was cast in a mold. That's not how I meant it, anyway. Sorry for the confusion.I suspect the iron which is plated over the copper is a high carbon iron such as cast iron or other perhaps some other form with additional ingredients. Cast iron for instance has high hardness and high wear resistance. Two features which would be desirable in a soldering iron tip. And of course, solder will readily wet to it. It is also much more rust resistant than carbon steel. Perhaps not as good as stainless steel, but stainless steel doesn't wet to solder, and it has poor thermal transfer compares to cast iron.One of my original points was that the iron plating on the average hakko tip is pretty thick. Mil or more. You can certainly judiciously file or sand it without exposing the copper core. The chrome plating is the part that can be better measured in microns.QuoteI'm not sure the definition of "plating," but certainly we "plate" iron over cylinder heads. And it's not elementally pure iron. In case of cylinder heads, the iron may contain high amount of carbon, including actual graphite, which is not unlike cast iron. In fact, cast iron is a type of iron which has defined amount of carbon, among other things. It is named so, because it in fact can be cast with relatively little warpage. We also cast steel, but there is no steel known as cast steel. So after we do the act of casting pure iron, or other alloys of iron, I suppose we can call these "cast iron," after the fact, but I think that would be somewhat vague, lol. At some point, all iron and steel is cast into ingots, but we have different names for these different alloys; names which are more useful. If the ingot is over 4% carbon, we call it pig iron. if it's less than 2% we call it steel. if I take a piece of cast iron and mill it into shape, I don't called it milled iron. So I will agree to disagree.

author: Specmaster
author_rank: Super Contributor
timestamp: July 17, 2017, 12:38:13 am
content: Quote from: IanB on July 16, 2017, 01:23:53 amI agree with turning the iron off, I do this, as you say, it is just seconds these days with a decent soldering station to get back to temperature. On the topic of temperature, 400C is most certainly too hot for most PCB work, especially with the really fine solder that you're using and the extra heat will make it too easy to lift pads / traces as it will tend to kill the adhesive that bonds them to the board, And it will certainly cause the tip to oxidise very quickly just like the old fashioned mains directly heated irons with no temperature control used to if you had a break in soldering for a few minutes.I tend to set my station to around 320 to 330C and that is sufficient for most jobs unless there is a large mass or a ground plane to suck away the heat, especially with a small tip as there is going to be insufficient thermal capacity for large bits of soldering.

author: IanB
author_rank: Super Contributor
timestamp: July 17, 2017, 01:11:15 am
content: Quote from: KL27x on July 17, 2017, 12:05:54 amIt actually does mean that. It means exactly that. The molten iron is poured out of a furnace into a mold where it solidifies.Quote

author: KL27x
author_rank: Super Contributor
timestamp: July 17, 2017, 03:22:05 am
content: @Ian B. Perhaps you can google the definition of cast iron and tell us what you find?

author: IanB
author_rank: Super Contributor
timestamp: July 17, 2017, 03:28:41 am
content: Quote from: KL27x on July 17, 2017, 03:22:05 amI did

author: CJay
author_rank: Super Contributor
timestamp: July 17, 2017, 09:15:04 am
content: Quote from: MosherIV on July 16, 2017, 10:59:41 pmI had to give up taking fun jobs* from one 'repairer' local to me because he was using plumber's flux on boards, including SMD, I realised when a job was returned to me as 'gone again' and the board was covered in green residue from the acid flux.* the difficult ones that'd been around half a dozen places and failed to be repaired

author: BravoV
author_rank: Super Contributor
timestamp: July 17, 2017, 09:20:32 am
content: From Hakko ..

author: KL27x
author_rank: Super Contributor
timestamp: July 17, 2017, 07:23:21 pm
content: http://www.freepatentsonline.com/y2004/0226981.htmlI bet this is how (at least some of) these iron tips are made. The iron is powdered and sintered in a die to produce the outer shell. The inner die is withdrawn revealing the hollow. The copper core is pre-swaged into gross shape; the inner iron sleeve is sintered separately, made like a blind rivet, which is slipped over a shouldered pin/mandrel, and this is hydraulically pressed into the copper/outer tip to swage everything together. The whole thing is then heated to melt the powdered silver between the layers to braze everything together. These are machined and polished to final dimensions. Then the chromium layer is plated on.It's possible that on the longer skinnier tips, the hole for the copper core may have to be drilled out of the sintered tip. Then the copper wire inserted and swaged to fit. Then the outer iron ground down to size. Bent tips... hmm. Perhaps they have a joint that is brazed, at the bend. Or maybe they are just bent, after the fact, using a ductile iron jacket. I doubt electroplating can be done this thick and be as economical (cheap) as these tips are. That would just be a PITA. I.e. expensive. The conditions would have to be surgical, and the tips would still require post plating machining to even out the lumps and bumps. (The first 10 microns is easy; this is how radio shack firestarter tips are made. After that, it is increasingly difficult to make the plating consistently thicker. The shoulder area of the hakko tip has several thousands of microns of iron "plating"). And the space required and upkeep/tweaking of the plating tank and equipment would be considerable.In any case,the iron is a cast iron alloythe carbon content of the iron is over 2%, otherwise it would be called steel.

author: John_ITIC
author_rank: Frequent Contributor
timestamp: July 18, 2017, 03:14:58 am
content: Buy this:http://uk.rs-online.com/web/p/soldering-station-accessories/5078698/

author: stj
author_rank: Super Contributor
timestamp: July 18, 2017, 04:05:40 am
content: it would be cheaper to throw the tip in the bin and buy some fresh ones!

author: BradC
author_rank: Super Contributor
timestamp: July 18, 2017, 08:32:44 am
content: Quote from: stj on July 18, 2017, 04:05:40 amIt would, but those tip cleaners will restore a *lot* of tips.

author: rolycat
author_rank: Super Contributor
timestamp: July 18, 2017, 01:44:22 pm
content: I find brass wool does an excellent job of cleaning tips, but many of the "brass" tip cleaning aids sold on eBay and similar sources are actually copper plated steel and are both overly abrasive and much less effective. The product pictures may also be doctored to look more like brass.

author: stj
author_rank: Super Contributor
timestamp: July 18, 2017, 02:30:22 pm
content: i get my brass cleaners from Rapid to hopefully avoid that problem.

author: KL27x
author_rank: Super Contributor
timestamp: July 18, 2017, 07:39:53 pm
content: QuoteI tried the little cans of tip cleaner/tinner when I had a Radio Shack iron with the pure copper tips with the micro-thin nickel plating. Wrong thing for that job. Those tips just die, and once the plating is gone, you might as well just file them. If you're counting on some black magic where this stuff restores the actual plating, it does not. It works by removing material, and the "tinning balls" in there might as well be regular solder. Don't get me wrong, it's good in the fact that is gets into nooks and crannies, removing mostly just the oxides and not the good metal. Also there is advantage in solder holding ability if you leave the surface textured/micro-pitted, by using a chemical cleaner. But in average tip, there is plenty of iron there, and the "gentleness" is not needed, if you stay away from the thin chrome plating.With proper temp controlled station, it is rare to ruin a tip at leaded solder temps. It's not that buying a new tip would be cheaper... just that a stone or sandpaper is a generally useful thing the rest of the time it's not needed for a soldering iron. It just depends on what iron you got and how you use it. I have tried to intentionally oxidize a bevel tip on my old velleman station. Trying to make a CF tip. I sanded the tip, tinned just the face, and left it at 450 for several hours. It still tinned like nothing happened. In hindsight, after reading this thread, I could have coated it with zinc chloride flux to induce surface "rust."Update on the steel wool. My own firsthand experience now says, yes. It's too aggressive. It is wearing away at the edge of the chrome plating, already. At least on the Chinese T12 tips. (But boy does it clean crusted residue - it gets down to the chrome, removing that last layer of residue that brass wool leaves behind). I can tell the difference between the real hakkos and the Chinese knockoff. It's the level of machining/polish on the tips before the chrome plating is put on. The Chinese tips have profound grind marks and also voids/defects from the casting/MIM or however the iron part is made. I'm sure the real Hakko chrome plating won't break/flake as easy. It's just a matter of how much time and $$$ spent in the manufacturing process.As an experiment, I filed away at the working end of the tip deep enough to remove the machine marks. No surprise to me, the copper is not exposed and the tip still works. I'm sure there is a lot more iron there. I have cut apart a few of them. If the iron was chocolate and the copper was caramel, it would look like the cross section of a Rolo. When you consider the prying/twisting forces you can put on these tips, you know there is considerable iron there for structural integrity as well as to protect the copper from dissolving. If it was just a thin electroplating, I would have bent some of my tips into pretzels, by now. Dropping the handpiece on the ground, point down on a CF15 tip, it would be bent at least 45 degrees at the base. Instead, this results in just a tiny curl at the edge of the tip.The very existence of the deep machine marks in the Chinese tips is indicative of the thickness of the iron. These kinds of marks would not be left on copper. Copper would be cut and swaged, and any grinding/polishing would not likely be so rough. The machining is surely done after the tip is made, just before the final chrome plating. If there's enough iron there for the factory to grind on it with what looks like a 60 grit belt, there's enough for gentle sanding, galore.