So you can get a really cool cheap USB powered soldering iron which is actually quite good.
They don't cost a lot from your favourite Chinese site or Amazon, eBay.
Have a search for "8W USB soldering" and you will find it.
The thing I got fed up with is that it has along lead which plugs into a USB power bank, so I decided to look for other options to power it.
This is what I came up with...
USB soldering iron (around £5/$5) or just a replacement tip (under £2/$2)
Good review and teardown on YouTube
E Cigarette EOSVAP Vape Starter kit - No Nicotine Electronic Cigarette Starter Kit - Amazon UK - B0798GV36T
Ego Vapour Town eGo-C Twist Variable Voltage Battery, 1300 mah, Black - Amazon UK - B00LYXC33O
These seem to be quite generic ecigs and batteries, they use a 510 style battery connector, so there are probably many others that can be used.
I must apologize to people in the USA as I can't seem to find the type of ecig I used on Amazon or eBay USA. Not sure of this is due to selling restrictions.
If anyone knows of a similar ecig, please let me know and I will add it here.
Step 1: Pull It All Apart :)
Well, it always best to take stuff apart, to see how it works,
The soldering iron only needs it tip removed.
Step 2: Let's Get Cutting - the Drip Tube.
Cutting is the hardest part, no going back if you make a mistake. You have been warned.
Get the top part of the ecig and trim the tube flush.
Step 3: Cut the Heating Coil.
Next, cut the heating coil holder down to the screw thread.
You can remove all the guts of it first to make it a bit easier.
Step 4: The Iron Tip Holder.
Once cut, I found the coil holder is almost the exact diameter for the tip to go through, except for the very tip of the tip. I used a round needle file to slightly enlarge the hole until the it would fit through.
Step 5: Cutting the Iron Tip
Now this is really critical!
DO NOT GET CARRIED AWAY
You will need to carefully cut the centre contact of the iron tip. This is very much trial and error.
Get the tip fitted to the coil holder, the battery adapter and battery.
Screw the tip/coil holder into the spacer and gently screw it into the battery. You will feel resistance when the centre contact hits the battery. If it is not fully screwed in, cut or file a little bit off.
Try not to get to rough with cutting/filing the contact to avoid damaging it.
Step 6: Finished Parts
So, all went well and you have now got everything ready to fit together.
Step 7: Wow, That Was Easy.
Yep, you are now the proud owner of a slick looking rechargeable soldering iron, that can live in your pocket for that emergency solder repair.
Step 8: But It Is Only a 650 MAh Battery!!!
Thankfully due to popularity of ecigs there are plenty of options of batterys that will fit.
All you need to check is that it is a "510" size thread and you can swap batteries with ease.
The one in the picture is a 1300 mAh, with variable voltage control, which will sort of affect the temperature of the iron. The more voltage means the iron will heat up quicker.
I managed to get 250°C with the 650mAh battery and over 400°C with the 1300 mAh battery on 4.8V.
Haven't tested for duration, but have removed a couple of LED's, 5 or 6 surface mount and some wires from a PCB using the 650 mAh battery and it still had plenty left in it.
One nice thing on the small batteries is that they have a micro USB charging socket on the base, so unlike the 1300 mAh battery you do not need a seperate charger.
The small batteries also have three settings, activated by pressing the button 3 times and the LED around the button will flash, white - high, green - medium and red low. The batteries can be switched off by pressing the button 5 times and the same for switching on for safety when carrying them in your pocket. There is also a 10 second timeout, where the button flashes 3 times, just wait for it and then press again. I found that I need to do this at least twice before the iron heated up enough to melt solder.
Step 9: Almost Forgot?
One last detail.
Where the mouthpiece went leaves a huge hole!!! Oh no, what to do.
Thank goodness for 3D printers. I have attached an STL file of the one I made in Tinkercad.
Printed in ABS at 0.1mm layer and then sanded and polished until it was nice and smooth, almost looks like it has always been there.
Step 10: Why Didn't I Do This Before.
The reason, I didn't do it before was because I got hung up on looking a other people creating completely new soldering irons, 3D printing new cases and adding big 18650 batteries.
All I wanted was a small, handy, occasional use soldering iron that wouldn't cost a fortune.
If you already have an ecig and find it as vile as I do, then even better to re-purpose it to something useful. If not then they are not really expensive to buy