Instructables

25-Cent Invisible Ink/Pen (UV light visible)

Have you ever wanted to get one of those cool invisible ink pens from the store so you can write secret messages to your friends? Or maybe you need to use it to mark peoples hands for admission to a party. With this Instructable, you can easily do so, and do it for only 25¢!!
 
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Step 1: Gather The Materials


There are very few materials needed for this Intstructable. These are listed below:

1 Highlighter (I got a pack of 4 different colors for only $1)
1 cup (plastic works best, so you don't have to worry about washing it out)
3 Tablespoons hot water
cotton swab
Pliers

Step 2: Take Apart the Highlighter

-If you want to make the pen, be sure not to lose or break any parts.
Start by taking the cap off. set aside.
Using the pliers, grab and pull of the front plastic piece of the marker.
Next, slide the ink cartridge out of the back of the marker.
Then, also using the pliers, pull the tip of the marker out.

Step 3: Extract the Ink


This step is not hard at all.
Place the foam ink cartridge and marker tip in the plastic cup
Poor the 3 tablespoons of hot water over the cartridge
Let the ink cartridge soak for about 5 minutes
Squeeze all excess ink from the cartridge, then let soak a little more. repeat until the cartridge is a light color, and the water is dark.

Step 5: Making the Pen


Take the Ink Cartridge from earlier, and squeeze it so that excess ink comes out. IT DOES NOT NEED TO BE DRY, JUST DAMP. You should be able to squeeze some out if you try hard.
Re-assemble the pen.
Start with marker tip, and slide it back into place.
Then, put the cartridge into the front part.
push the front piece onto the back piece.
put the cap on.

To use, write with it. to view, look at with UV light.

Troubleshooting:
if you can see the marker when you write, then you need to squeeze more ink out of it.
If the marker isn't writing, then you need more ink in it.

Step 6: Storing the ink

Picture of Storing the ink
To store the ink, poor into a small, watertight container. BE SURE ITS WATERTIGHT, UNLESS YOU WANT INK ALL OVER YOUR CARPET. I used a medicine bottle. Also, it might be a good idea to label it.

After your marker stops writing, simply soak it in the ink for a little more, and squeeze the excess out!

Step 7: Other Tips

the ink works best on skin
Don't where white clothes, and do it somewhere where you can wipe the ink up it it spills.
need a black-light? Home-Depot sells some Eco-bulbs for around $6, Walmart sells a lamp for around $10, and Amazon has a Chauvet Handheld Black light for around $6.
I have 2 of the lamps, one of the bulbs, and one of the handheld ones :) They all work great, especially for the price.

Vishvesh11 days ago

can it work without uv, and would it work in a normal room instead of dark room?

sadil31 month ago
Can we take a marker instead of highlighter ???????
If not then can we use the other highlighter its a little bit fat....

Please answer and thnks in advance :)
expertnoobz (author)  sadil31 month ago

It only works with highlighters because of the neon color. But I suppose if the marker is neon it might would work. And yes, any highlighter will work, it doesnt matter the thickness

BluesBayou11 months ago
why do you have one sock on and one sock off?
batonas2 years ago
theres a black light leds, I would put one of those leds in a lighter so it wouldnt look that suspicious, it would be less bright but more stealthy.

heres a list of fuluorescent stuff by wikipedia

laundry detergents containing optical brighteners
soap
Body fluids (those are free)
sunscreen


wolf996 batonas2 years ago
Body fluids (those are free) SICK!!!!!!!!!
Daxuto wolf9962 years ago
In the good way, right?
wolf996 Daxuto1 year ago
I Hope So I Haven't Tried Jizz Yet Though
Daxuto wolf9961 year ago
Honestly, tried with a black light, saw nothing, but I dunno.
wolf996 Daxuto1 year ago
What Using Jizz? It Shows Up Really Well
lukas_tek2 years ago
hey expertnoobz!
i need know one thing
the ink is visible under light of blue led?
expertnoobz (author)  lukas_tek2 years ago
I'm not sure, i don't think it would be. I would test it out, but I don't have any blue LED's at this time.
ok thanks
i will test it out when i go back to my house!
i'm travel and i still conected!
expertnoobz (author)  lukas_tek2 years ago
Cool, let me know what happens!
OT4 expertnoobz2 years ago
I know withought testing it that it does not work with a blue led.
ok!
rimar20002 years ago
Very interesting!
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