My soldering iron tips frequently turn black and do not hold solder property. I tried by filing them on smooth file but of no use. Tried with flux also but no much use. How do I go ahead?
Based on my experience in micro-soldering, I maintain my soldering iron tip dipping it on flux and scrape off the burnt flux on fine metal soldering sponge and while the tip still emmit smoke I gently apply soldering lead on to it to cover the clean part and avoid oxidation. Works great for me.
It's a common problem when you turn the heat to max. I took example from youtube videos and personal experience. I found that 300-370c is the best temperature range that keeps the tip oxide free for longer. You can clean the tip by shocking the oxides of and wiping it on a damp sponge, or use a steel brush to regain the mirror like finish.
At that point it's probably best that you replace them, and then take care of them from there. When you're done using the iron, clean with brass wool, add solder to cover the tip, and then turn the iron off. I really like my Hakko because it has a sleep function, I can just add a bit of solder and drop it on the holder to sleep when I'm not using it. Then at the end of the day I can repeat the same thing, but power it fully off.
I guess im a bit late to tell not to file down your tips.. Proper tips has microcoating on top of them to prolong their life, and the moment you damage it with file and so, tip is gone.. Main issue is that people doesnt apply solder to the tip before turning the iron off, a lot of people like to clean the tip and leave it clean, it allows it to oxidise -- before turning iron off, clean the tip and apply new fresh solder, let it stay on the tip so it protects tip from oxidation. For using wet sponge - make sure that your tips does support it, i have ruined expensive tip with such mistake, it stated in the datasheet that the tip is not wettable and should be cleaned only on dry sponge.
Never scrap or file the tip. Once you do, it's only a matter of days before it becomes useless and solder won't stick. Tip tinners are also bad. Tinners should only be used to extend the life of a dead tip until you buy a new one. The proper way to maintain a tip is to use it gently and not use it as a grind tool to scrape stuff off the board. Clean the tip using a brass wire ball and apply solder to the tip. Keep the tip covered with solder until the next use to prevent oxidation. If solder is not sticking on the tip, add a little flux and try again. If solder still does not stick, you'll need a new tip and you can use a tip tinner in the meantime.
Check https://northridgefix.com/product/soldering-iron-tip-cleaner-rosin-flux-core-to-prevent-oxidation/
try to left a tin blob before you put down your soldering iron. it will prevent the oxidation. but remember to wipe it clean before you use it again.
As said above, never scrape or sand the tips because it removes a very fine layer of factory coating protection on the tip.
Brass sponge or damp cellulose sponge, though I have read that the damp sponge can produce thermal shock to the tip.
What I do when it gets bad and no solder wets a dirty, oxidized tip anymore is to put a drop of flux on a surface, iron to 315°C, dip in flux and then wipe a few times on melamine foam aka Mr. Clean magic eraser white side. Repeat a few times. As you know melamine does magic for cleaning smooth surfaces, and the result is a tip like brand new shiny. The foam is not abrasive like sandpaper so the tip is still protected. Then fresh solder on the tip to protect it and let cool naturally to room temperature. The flux helps with cleaning the oxidation, you can use plumbing ZnCl flux to clean the iron tip as well, once it's well wiped off after and no reside remains to get on a PCB to corrode it. Always wipe the tip on a brass sponge/melamine and then tin it on a hot iron before switching off so it will be protected from high temperature oxidation for the next time.
I have brought back 2 tips so far from being dead, I had already chucked them in the bin. They're like new again and working fine for many months.
My soldering iron tips frequently turn black and do not hold solder property. I tried by filing them on smooth file but of no use. Tried with flux also but no much use. How do I go ahead?
You've touched on a subject that's been one of my pet "peeves" for many years. First and foremost, modern iron-plated tips should *never* be cleaned with a file or a steel wire brush. It, plain and simple, destroys the tip.
A fresh tip has to be "cured" when first heated up by keeping it flooded with good rosin-cored solder - at least for the first 5 or so minutes. Once it is cured, there are a couple of methods of cleaning that work, depending on the tip manufacturer's recommendations. If a cleaning sponge is used, it *must* be saturated with clean water. A moist sponge won't do - saturated. The water vapour - the steam - from the hot tip touching the _wet_ sponge does 90% of the cleaning. If you don't have a sponge available, the best thing is a brass tip cleaning bundle (available from many sources and looks like little curls of brass ribbon). Once you clean it off, make sure that you re-tin it with a small amount of fresh solder to keep it from oxidizing. If a tip becomes contaminated with something like plastic, you can gently clean it off with a fine grade _brass_ brush - never a steel brush, again followed by a good re-tinning.
When you're finished soldering, clean the tip off and re-tin it before you turn off the soldering iron; never store it with the tip un-tinned.
A tip cleaning/tinning compound (the kind that comes in a little round can with a lid) is generally never recommended, as many utilise an acidic compound mixed with solder powder and flux to forcefully clean the tip. That acid is a big no-no on modern tips. There are, however, a few out there that are just 63/37 solder powder plus rosin flux *without* the acidic component (usually aluminum sulfate or ammonium chloride or a related sulfate or choride compound.)
I use HAKKO FS-100 chemical paste. It's designed to re-tin your tips and it works very well.