How to remove oxidation from the soldering iron tip - check this video out
Before going into detail about “how” and “why?” here’s a video for you:
Why to make a post about that?
I’m a member of a lot of DIY subreddits, and I see there are a lot of similarly looking posts created over and over again:
- Why does my soldering iron tip look burnt?
- Burnt tips or bad soldering iron?
- Soldering iron tip blackened and won’t melt solder
…and so on. In all cases, they are posted by people who are very new to soldering and don’t know yet what is expected and what is not.
What is considered “normal” for soldering iron tips?
Some of you might be surprised, but as you start using your soldering iron, the tips lose that brand new look very quick, within minutes, in some cases. Especially if you use a $12 60W soldering iron from a hobby store.
It’s perfectly fine to use such a soldering iron; you just have to be more cautious and switch it off if you are not going to solder anything in the next 5 minutes. Why? Because it has a 60-watt heater that constantly heats and would eventually overheat the tip past 350-400 degrees Celsius, speeding up the oxidation and shortening the tip’s lifetime.
Not all soldering irons are made equal
In the last couple of decades, I used different kinds of soldering irons:
- a couple made in USSR (one with a copper tip that wasn’t removable, another with a removable tip that’s held with a screw),
- a few ones compatible with 900M-T tips (you can see that type of tips in the photos on this page) but without any regulation,
- then a few adjustable ones but without any sort of thermal control (because the regulator just changes how many watts of energy go into nonstop heating),
- and finally — a thermally controlled one, part of a soldering station
They can all be used for soldering electronics but require different amounts of effort to do a good job and preserve the tips in good condition. Some take 5-10 minutes to reach good temperature, others work okay, but tips get dark-brown within minutes of use and have to be cleaned more often, as solder stops sticking to them, others just work with minimum maintenance needed. If you are going to do a lot of soldering - consider getting a soldering station with a thermostatic iron. It has a thermistor that reads the actual temperature of the heater and uses that to control it — to add more power when the iron touches metal and loses temperature because of heat dissipation, and to reduce power draw when not in use, so it doesn’t overheat in idle state.
I can’t recommend specific models, but Hakko is considered one of the best brands for soldering stations in terms of cost/quality ratio. Yihua is a cheaper alternative, but opinions differ on cost/quality.
There are portable (USB-C powered) soldering irons like Pinecil - they are pretty good compared to the cheap adjustable (but not thermostatic ones) irons because they will keep the temperature you choose, but they may not be powerful enough for soldering thicker wires and highly depend on the power source wattage. But hey, they look cool and are portable — that’s nice.
But now, let’s take a look at the soldering iron tips (the 900M-T type ones specifically) that I have at home.
Example of absolutely normal soldering iron tips
Here is a photo:
From left to right:
- This tip was never used.
- This chisel tip was used with a temperature-controlled soldering iron for a few hours, cleaned between uses, and stored with a bit of solder on the “working” surface.
- This tip was used, but less than the previous one. The same temperature-controlled iron was used, but the tip needed to be cleaned after the last use.
- This one has a cool blue tint, caused by a high temperature because it was used in a cheap soldering iron that would heat nonstop until it was plugged off. Nothing bad has happened to the tip; its working surface is tinned and clean—that’s the most important part.
- This one looks the worst—it’s dark brown, and the tip is covered in dull solder. It’s been used with a cheap soldering iron and with a more aggressive flux (plumbing flux; I’ll add more details about that in the next sections). This one will be used in the video to show how to clean it.
- Also, I have a slightly used tip with a drop of fresh solder on it—nothing special about it; I just wanted to show what I have lying around.
They all are absolutely fine despite absolutely different looks. Some were used with cheaper iron and exposed to higher-than-optimal temperatures, but they are still usable. Just some cleaning is needed.
Please note, the dark brown doesn’t mean the tip is bad/burnt/destroyed/whatever-else-you-can-say-about-it. They are all made of multiple layers of metal, and the only important part is the very tip - just a few millimeters of it. Everything else may look silver and shiny, dark or dull - that doesn’t matter if the tip is clean and undamaged. The tip is covered with a layer of alloy that allows the solder to easily stick to it. That’s the most essential part.
Unfortunately (for you), I didn’t have a “destroyed,” completely unusable tip to show you how it looks. It would look similar to number 5 in my example, but with one very critical difference — solder won’t stick to it anymore because the outer layer is completely worn out for one or multiple reasons combined:
- abrasive materials used to clean it
- aggressive flux was used (like one made for plumbing)
- tip tinner was used too often (I don’t say “don’t use tip tinner,” but don’t use it every time you need to clean and re-tin the tip; use it only if simple cleaning doesn’t cut it anymore)
- overheating caused oxidation that entirely ruined the outer layer of the tip beyond repair
Why do tips look “burnt”?
Soldering irons use relatively high temperatures to melt the solder—usually 180 degrees Celsius and up. Suppose the soldering iron tip isn’t covered with solder. In that case, the top layer of the metal will oxidize because oxygen from the air is contacting it. The hotter the tip is, the faster oxidation will happen.
If the tip was covered with solder, it might still look burnt or at least dirty over time. Why? Because solder also oxidizes, plus there’s a chance there is some flux, rosin, or dirt burnt on the surface now—that’s considered normal if you use the soldering iron.
So, the tip looks burnt because of oxides and all sorts of gunk that might develop there during soldering.
What do you do to keep the tip clean?
You’ll have to clean it periodically. How often - depends on temperatures, flux/rosin, solder, dirt on the materials you are soldering, and so on. You have to wipe/scrub off the old oxidized solder, gunk, and oxides off the tip. But you have to do it carefully - don’t scrape off the outer layer on the tip, or it will become completely unusable, and solder won’t stick to it. I’ll describe what not to do when cleaning the tips later in this post.
After the tip is cleaned, you will have to tin it (apply solder to its surface so the tip won’t oxidize, and solder will oxidize instead. It’s considered cheaper to buy solder rather than new tips).
What can be used to clean the tip?
There are different materials/tools you can use to clean the tips. In most cases it’s better to have more than one option, as they work differently.
A piece of cardboard - when you are out of options
What would McGyver do?
The cheapest option - whatever piece of cardboard you can find at home.
It’s the least recommended way because it’s a fire hazard.
You can scrape off old oxidized solder and whatever is left on the tip and get burnt over time with a piece of cardboard. But please only use it if you are out of other options.
A sponge
It’s a sponge that you need to moisturize so it won’t burn on contact with the hot soldering iron tip. It shouldn’t be dripping wet, just damp. If it’s wet, you can damage the soldering iron tip due to thermal shock on contact (most likely not from the first try, but anyway - it’s better to avoid quick changes of temperatures).
You wipe all the solder and dirt off the tip with it. It would take a couple seconds to do that. In some cases, scraping off gunk that has burnt on the tip from the first try might be difficult, so consider the next option.
Brass tip cleaner
This option works the best - you can scrape off all the dirt/oxidation, and it wicks away all the solder. Make sure you don’t buy a steel sponge, as it will 100% scrape off the outer layer of metal from the tip, which we don’t want to happen.
You will have to replace that brass sponge when it soaks too much solder.
Oh, I almost forgot about that - a tip-tinner paste
This is basically a more aggressive flux mixed with tin, so it would try to remove those oxides from the surface but would also “eat away” some tip’s surface. Unfortunately, I don’t have an example picture to show at the moment.
Want to clean less often? Use flux instead of rosin
While both serve the same purpose, flux is easier to work with. It doesn’t burn as badly as rosin, so it leaves less gunk on the soldering iron’s tip, and it’s easier to apply than solid rosin.
What if you use a solder wire that already has a rosin core in it? Good for you - but get some flux anyway. Very often, more than the rosin core in soldering wire will be needed because you’ll likely need more than one attempt to solder two wires together, at least at the beginning. And without rosin or flux, solder won’t stick to (or, more appropriately, “won’t wet”) the wire. Such joints may fail quickly for obvious reasons (insufficient wire strands held together with solder).
Beware of plumbing flux - don’t use it for electronics!
Flux can be sold in different forms - paste in plastic jars, syringes, etc. Make sure you buy one made specifically for electronics, not plumbing.
Very often, plumbing isn’t mentioned directly on the flux packaging.
Here is an example:
You may notice such things as “non-toxic” and “non-acid,” which are good, but what is most important — is in the usage directions, it says “flush inside of pipe.”
This is 100% plumbing flux—please don’t use it for soldering electronics. If you don’t clean it off thoroughly, it will oxidize all the joints it touched and accelerate the oxidization of the soldering iron’s tip.
What to avoid?
Anything that would damage the plated tip:
- abrasive materials like wire brushes, steel sponges (ones used for dishwashing), sandpaper, steel wool
- aggressive fluxes (ones used for plumbing, the example was shown above)
How to store the tips
After you’re done soldering, clean the tip and add some fresh solder so it covers the tip. This way it will prevent oxidation while the tip is not in use.
Conclusion
Some darkening of the base of the soldering iron tip is normal - most of the metals will change color if exposed to high temperatures.
Unnecessarily high temperatures will increase oxidation - don’t crank up the temperature without the real need. Don’t use tip tinner every time you are cleaning the tip or finished soldering - it will damage tip’s surface if applied too often.
To prolong tip’s shelf life - clean it and apply fresh solder after you’ve finished soldering or are switching to another tip.
For more tips (haha, I almost hate the word at this point — it’s been used too much on one page) and tricks, please consider adding this website to your bookmarks and visit it periodically. At some point I’ll add email subscription option and social network links, I promise.