Today all of use ball pen but students and some people still use fountain pen. What this pen allows is the correction because the ink used in these fountain pens can be erased by ink removers.
This invention is one of my very old inventions when I was a class 7 student. I use to do lots of spelling mistakes due to which I needed a ink remover. So here’s that formula for you to discover and start making yourself your own ink remover. You can actually start a factory of it, no kidding since it’s so easy and cheap to make, soon you will be making huge profit

To start with let me tell you what you need:

1. Water
2. Common salt
3. 12v 1AH battery eliminator / charger (see here)
4. Pencil led
5. Thick copper wire
6. Beaker

So as you can see these are not very costly items, most probably you will be having all these items in your house. If you don’t have a beaker you can use any cup / mug which is either of plastic or glass (no metal).
So now let’s start the fun, fill about 100ml of water in beaker and add half teaspoonful of salt and mix it water well. Now take think copper wire of about 4cm in length. If you don’t have think copper wire then you can combine many thin wires to make a thick one. Connect this cooper wire to negative (-) terminal of battery charger and dip it water as shown in figure. Now take about same 4cm in length a normal pencil led (take it out from a pencil) and connect it to positive (+) terminal and dip it in water. Make sure both of these copper and led electrodes do not touch each other. Now switch on the battery charger. You will see some brisk effervescence and bubbles. Keep it going for few minutes until you notice a smell and the colour of water changes to pale yellow. As soon as you see the change in colour, switch off the current and take out the electrodes, your ink remover id ready now.

To test it, use your fountain pen, then put a small drop of ink remover to erase it J. For your ease, keep this liquid in small plastic bottle (use thoroughly washed eye drops empty bottles). This ink remover also works for some thumb pad inks etc. if you find it working for some other inks also, do tell it here in your comments.

Hello friends! Today I’ll tell you how you can make yourself a soldering iron within few minutes whenever you need it. So what’s the need of this when we can easily get a soldering iron for as low as Rs.25/- ? I have a reason, first of all it’s not very common equipment that every home must have but then sometimes we strongly need it when we find a broken solder joint.

To make this quick and cheap soldering iron all you need is a 12v battery charger/eliminator (~ 1Ah rating), the one which I have shown here will do, a small pencil (a discarded one will do) and of course soldering wire. Carefully using blade of something sharp, take out a small piece of led from pencil (about 2cm and not more than that) and fit the one end of it to any one of the terminal of battery charger and your soldering iron is ready! It may look like small welding machine but it works beautifully.
Now to sold, what you need is to connect the other terminal of battery charger (other that which is connected to pencil led) to the soldering wire. Having all this done lets try the soldering job!!
Switch on the battery charger and for fraction of second touch the soldering wire and led, it should give a small spark which means soldering iron is ready. To sold, just touch the soldering wire and led to the point where you have to sold and keep it touched for few seconds, you will see that wire will melt and you can solder joints with it. You can even work on PCB with this.
Note: Don’t keep the led and wire touched for long as it will lead to over heating of battery charger and may damage it. Also don’t work with sensitive PCB’s which have SMD components on them as spark created with this solder may damage those parts.