There are many instructables and DIY guides of how to make replacement tips for soldering irons, but they are all for soldering irons where the heating element goes around the tip instead of inside it.
Sure, i used to have on of them plug-in-the-wall soldering irons some time ago and i would whack an old nail in it every other year and solder just fine. But my soldering station, a YaXun® 936 (one of MANY Hakko 936 Knock-offs) has an iron with a tip that houses the heating element inside it (much like the original Hakko).
The tips for it are available online but are fairly expensive for me, to put in in perspective, the soldering station is being sold online (locally) for as much as a new 19" LCD monitor, and the original Hakko tips are more expensive than the whole station. The YaXun tips are also available and cost as much as a lunch, heck, the handling is almost as expensive as the tip itself but i decided i wanted to save that money for something else instead.
So this instructable is directed to those people that have a soldering station for working and/or feeding their hobby, and don't want to buy new tips for them because they live in a poor country and its hard for them or just because they wanna save some money and use something made by themselves. Or both, why not?
Additionally, the tips i made for my own Hakko Knock-off chinese station have a very good chance at being perfectly compatible with an original Japanese made Hakko soldering station, since its already a known fact that original Hakko tips fit these clones perfectly.
Step 1: Tools, Materials and Precautions.
Alright, i tried keeping it as simple as possible, you can even do this without any power tools at all (it would be the hell of a lot of grinding with a file though).
Even so, if you have better tools or a better way to complete a step i invite you to do it and school me about in the comments, take pictures, i may include them here to improve the instructable.
These are your basic tools:
1.- A threading kit, this will probably be hard to find depending on your situation, if you can't get a hold of the full kit get at least a 12nc24 tap and cutting die with their stock and wrench since its the only ones we'll be using. Ask someone with an old car/truck or your local mechanic, they are sure to have one of these around.
2.- A file, you really need this one, specially if you don't have power tools for grinding, it has to be fine but not too much, you will be using it a lot. It doesn't need to be in good condition, copper is a soft metal so even that old wasted file i used did great with it.
3.- A knife sharpener small enough to fit the 5/16" copper pipe, or at least a metal piece that fits inside it, you will need it to smooth the metal inside a little.
4.- A bench vise, or at least locking pliers. Highly recommend the bench vise, it will make your life easier. Again, your local mechanic will surely have a vise on his work bench.
5.- A hammer, a small one will do, even a smooth rock if you have to. We won't be doing any heavy hammering.
6.- Pliers, 2 of them. Or at least 1 and some creative use of your bench vise/locking pliers.
7.- Your soldering iron, for fine tuning and fitting of the tip as you produce it, keep it near, out of the way and with its original tip removed.
8.- A metric ruler. Yep, metric for the win. if you can't get a hold of one (how...?) keep your original tip around for reference and measuring.
9.- A piece of wood, this is just in case we need to whack things into shape and the hammer is too much for that.
10.- A hacksaw, make sure the saw is in good condition, had quite a lot of issues with an old wasted one.
11.- A Phillips screwdriver, an old one of normal size, we'll use it to shape some copper out of the way, so yeah, it better not be your favorite screwdriver since we are gonna use it roughly.
12.- Protective gear, least but not last, some basic protective gear like a good pair of working gloves and protective glasses are a must, work boots and ear protection are a should.
Now your materials:
1.- A piece of 5/16" (8mm) copper pipe, this is one is easy, they are used for LPG gas canisters pigtails/regulators, they get really roughed up when changing the cylinders so they break a lot, surely you have one around in your scrap pile or maybe your neighbor has one in his scrap pile.
2.- A piece of 6 AWG solid copper wire, usually used for earthing. If you can't get a hold of it a piece of cylindrical copper or brass that is more or less the same diameter of the pipe will work, but it must not fit inside it.
We will be working with metal, so some basic precautions should be taken specially if you are going to use power tools. The 3 golden rules are to protect your eyes, your hands and have a good surface to work on (AKA don't "work on the air")
Also, google images for "copper poisoning", i don't need to tell you keep your hands off your face while working and wash them after you're done, right?
Not like you will get it from working with such small amount of copper for such a short time but better safe than sorry.
Power tools should be treated with respect, ALWAYS wear hands and eyes protection while handling things like a drill with a grind bit or bench grinder, if you have some experience with them avoid handling them while completely alone in the house in case you need help and if you have no idea how to use them have an experienced person do the steps that require them for you.
Step 2: Processing Your Materials
We are going to cut what we really need for the project from the materials, hacksaw in hand!
Once the final cut has been made we'll call the copper pipe "jacket".
First, we need to make sure we remove the brass pieces off the pigtail and any irregularities in the pipe (like that trumpet-like end, or cracks) and toss those back in the scrap pile for selling or future projects, also cut the pipe into an easy to handle piece, pigtails tend to be already of decent size to work with but if you feel its too long, just eliminate what you think its in the way. You can achieve this with the hacksaw or a pipe cutter. Keep in mind that copper is a soft metal so be careful while cutting and protect your hands with gloves.
Once we have a pipe and nothing else we need to eliminate those curves, it needs to be as straight as possible without deforming the tubular structure of the pipe. Bend it into place with your hands and do the finishing touches by softly hammering it with the piece of wood or hammer as you see fit.
Once its cut into a 1.5-2.5cm piece the copper wire will be called "bit".
Same procedure as before with the copper wire, straighten it as much as possible, bend it and then fine tune with the wood stick/hammer.
We need to work the wire to make the bit tip and its far easier if you have a piece of wire the length of your hand to move it around and to give yourself some mess-up clearance and proper grip, so use the hacksaw to cut an easy to handle piece of wire some 15-30cm long.
This can be replaced with a similar gauge brass wire if you have one at hand.
Step 3: Making the Jacket
For the jacket we will use exactly 2.5cm of the 5/16" pipe (mmm... mixing my units, fine, 8mm pipe), carefully measure it, mark the pipe at the 2.5cm mark (with a nail or even the hacksaw itself, just make a clear scratch where you need to cut) and use the hacksaw to cut the pipe on that mark.
Cut slowly and make sure beforehand that your saw is in good condition, copper is a soft metal and the saw may get stuck and jump out scratching the metal or even worse, scratching you, wear work gloves.
Once you have your jacket cut, we'll proceed to remove material that bends towards the inside of the tube when you cut. Grab your Phillips screwdriver and stick it up both ends of the jacket, grind back and forth with considerable strength and check the pipe from time to time, you should notice the openings widening not because the pipe is expanding but because you are removing the shoved-in material.
Once you can clearly see that the inside of the pipe is the same diameter than then entrances, grab your soldering iron and try to slide the heating element into the pipe, it should get in perfectly, like it was the original tip. Otherwise keep at it with the screwdriver.
Now we are gonna file the jacket, remove any extra material and smooth the edges, remember to be firm but loving with the file, copper is a soft material and you may end up ruining the piece if you use too much force on it. Read the annotations on the pictures for a how-to-file.
Step 4: Making the Bit.
The bit is made out of copper and its what goes on the tip... of your tip. Remember, for this, a cylindrical piece brass the same diameter of the jacket can also work, however i can't guarantee that any other metals will work for a tip or that you will be able to shape them as easily as copper or brass.
For the bit we will be using that 6 AWG single thread grounding wire because it just so happens to be the perfect diameter for this. And because i picked some discard from people grounding light posts here and its what i have at hand. Copper is never garbage. Ever.
The bit itself should be somewhere between 1.5cm and 2.5cm long. The longer you make it the better since you will be able to grind it back into shape when it eventually erodes away due to use, but do try to stay below 3cm to keep thermal efficiency up.
Like i said before in processing, we won't be immediately cutting the wire into a 2.5cm long piece of copper, we have to shape it first, but If you have a whole coil of the wire, sure, cut it into something smaller and easy to handle.
File or bench grinder?
We have to make the initial conical tip, this requires you to grind out a significant amount of material off the wire. It's perfectly possible to do it with a file but even grinding aggressively it will take you hours (the first one i made was with a file, took me 2 hours of non-stop grinding), i highly recommend you get 10 minutes worth of bench grinder time from your local mechanic or the neighbor that has lots of tools (there is always one). A drill with a grinding bit firmly held on a bench (with a vise or better, a bench drill) will also work greatly.
The shape you are aiming for its a sharpened pencil, we will work this mildly useful cone tip into a very useful chisel tip. Since i used a bench grind for this process i could not take any pictures of it while functioning (we have a still pic instead while its turned off) because i needed to concentrate and use both hands for it.
You absolutely need gloves and protective glasses for this, there will be tiny metal pieces flying at high speeds at your face and body, the copper will get very hot very fast while grinding, more reason to wear gloves and to have a water pot nearby.
Just to be perfectly clear: be careful around power tools, I'll repeat this as much as i have to. If you have little experience with them have someone supervise you, if you have none, have someone with experience make this part for you, just hand them a pencil and tell them "i want this with 2 flat sides like a chisel" and they'll be done in 60 seconds so no need to risk your fingers.
To make the cone, first grind the top of the wire in a 45° angle, remember you need to press and spin the wire as you grind to get an even and centered cone, then work your cone from there grinding its lower end and then normalizing the rest of the tip on that new angle, rinse and repeat until you have a tip that looks like a sharp pencil. (refer to the illustrations).
The cone must be made of sharp, straight angles when looked at from the side, you don't want a funnel or rounded shape (with a "belly"), so make sure to grind firmly and uniformly. If you mess up, no problem, just keep grinding until you are satisfied with the results, you have space for mistakes anyway.
Finally, hold the tip on the grinder for a couple seconds in a single position without spinning the wire to create a flat face, then do the same on the opposite side during the exact same amount of time with the exact same amount of force, that should give you a chisel shape. You can grind off the sharp tip off now or do it with the file while refining later on.
Now we cut and refine.
Use the hacksaw to cut your bit off the wire, remember, 1.5-3cm long from the very tip. i cut mine at 2.2cm long. You can also use some heavy duty wire cutters to cut the bit (its far easier than using the hacksaw really).
However you cut it, that flat bottom area needs a lot of attention from the file, it needs to be able to stand perfectly vertical on it, so it needs to be as flat as possible. The reason is, the tip of the heating element will be touching this part, better to have as much contact as possible.
Make sure of removing all the spare material and softening all the edges made while grinding, if you didn't with the power grinder, file the very tip off and make it a very small flat area, like a chisel. Also file the edges of the bottom a bit, it will help for the next step.
Step 5: Bit and Jacket Threading.
Now we will make use of that threading kit, i realize this tool may be cheap and basic for many but i had a hard time finding someone that lent me one, buying it was completely out of the question, they cost a fortune here and i wouldn't make much use of it.
Local mechanic friend of mine lent me his kit, and via the magical method of "eye balling it" i found that the 12nc24 tap and cutting die were exactly what i needed.
1.-Because its the most sound mechanical grip solution i could think of. For my first attempt at making a tip, i tried fusing both parts via the good 'ole hammer whack... its usable but... well, you'll see a picture of it later on, besides, there is a real chance the bit will just come loose one day because the bond isn't anywhere as strong as a screw.
2.-Because I don't have access to or experience with welding equipment capable of welding copper, and i would imagine that such a small piece would be problematic to weld even for a professional. Soldering it with tin is out of the question for obvious reasons, so a mechanical solution is preferred.
3.-Because when the bit finally becomes unusable due to normal wear & tear, i can just unscrew and replace the bit, keeping the jacket, and saving myself half the work of making a whole new tip.
The male and female.
Pick where to start, with the jacket or bit. Either way, i used locking pliers for this step for the sake of simplicity , but i highly recommend a bench vise, it allows you to use both hands since you won't be holding the pliers so its much easier to work with.
I will stat by threading the inside of the jacket with the tap and its wrench:
Make sure to apply plentiful light oil before threading. Some light motor oil does the trick. (as recommended by the kit owner)
For this step you will have to deform the pipe, but be careful not to over do it, you will have some bending to do later on. Grab the jacket on its uglier side with the bench vise/locking pliers until the pipe bends but don't close it!, this is to secure it into position.(refer to the pictures).
Next, making sure the jacket is aiming directly up (vertical), grab hold of the pliers with one hand and start threading with the other, taking very special care that you are doing it flat on the horizontal, you don't want a tilted thread.
Afterwards, you can bend the lower end of the jacket back into a circular shape with some regular pliers, or by carefully using the bench vise.
The bit will require you to use some cardboard on the locking pliers or bench vise order to protect the tip. Remember we will be working the bottom area. Secure it in place and start threading with the cutting die (that should be oiled properly before starting) again making sure you are going flat on the horizontal.
Thread until your heart's content (doesn't need to be much really, use the pictures as reference). don't try to screw anything in just yet. We'll do that next step after some TLC.
Step 6: Bit and Jacket Refining and Marriage.
Get a bit of steel wool or just a steel scrubber from the kitchen and scrub the threads on the bit. And yep, you guessed it, its file time. Grind down any sharp edges on the bottom of the bit and, if you find any on the jacket,grind those as well.
Grab the knife sharpener or the object you have at hand for replacing it and refine the interior of the jacket slightly use your soldering iron as reference, if the heating element doesn't fit, grind the jacket until it does.
We will now grab the 2 regular pliers, wrap them in cardboard and grab both jacket and bit and attempt to screw them together, i call this "marriage."
There will be some resistance because the threading is new and because your inner refining may have moved some waste material into the threads of the jacket, but that is why we are using 2 pliers for, apply force until they run the whole threading, and then unscrew them and screw them back together until there is no resistance at all and you can easily do it with your fingers.
Wash both the bit and the jacket separately with some grease removing detergent, we want to remove as much of that oil as we can, dry with a paper towel and marriage them again for the last time until wear & tear takes them apart.
Step 7: Polishing and Optional Nickel Plating.
Finally, you will now polish what remains of that murk away from the copper and leave it spanking and shiny by any means you think necessary. The use of chemicals for this is entirely unnecessary, just do some rubbing.
And good news, finally got a decent camera (a tad bit late for the process unfortunately) so you get some pictures you don't have to squint your eyes to look at. And yes, i cleaned my nails, proof is available.
After polishing, your tips are ready for use as pure copper tips. But as someone that has been soldering for a few years (just a few) i can tell you from experience that when a tip starts showing copper it doesn't have much life left in it, if it still usable at all.
Copper will naturally alloy with tin and just wash away as you solder, copper tips don't remain in good shape for as long as iron coated tips do, so you will be visiting mister file before long with these.
Coating the tip with iron is a massive pain in the behind according to my research, almost impossible for the regular hobbyist, but you have an option:
Nickel plating is surprisingly easy, fun and safe to do, and the materials needed are really easy and cheap to get, I got all of mine from my scrap pile and kitchen for free!
Its also extremely useful for many applications like protecting your tools from rust, or protecting metal from corrosion.
By nickel plating your tips they will not only look better by avoiding the burn marks from the heat but they will also last a lot longer because nickel will protect your copper tips from corrosion and from alloying with tin so, i highly recommend you follow this Instructable by A_Steingrube to do so, i did and it worked absolutely great.
That is all.
Tell me what you think of it, if you think i can improve the process in any way by all means let me know as well. Some of the pictures are of quite low quality and i apologize for that but while producing the tip i was pressed for time (i was kinda in the way of people working to feed their families in a mechanical workshop) so i took whatever pictures i could with my crappy smartphone camera as fast as i could.
Also, English is my second language and even though i speak it fluently (quite proud of it as well) I'm sure there are mistakes in the text, so if i made any or if you think some rephrasing needs to be done somewhere let me know as well. Thank you very much for reading.