Introduction: Real Thumb Drives!

Picture of Real Thumb Drives!
With this Instructable, I intend to show you how to make your USB Thumb Drive into any shape you wish!

I've been collecting USB drives since they started getting cheap. Every one of them still works, but unfortunately, the cases that hold them never hold up. I carry one on my keychain for a couple of months and the frame breaks off. I've seen Some others put their thumb drives into Altoids tins, but what benifit has that other than the initial Wow! factor...

I decided that I was going to cast my thumb drive into my own thumb! Unfortunately, I'd never done any type of plastics casting. Perhaps this was fortunate because I didn't know it couldn't be done! I just thought about it for a couple of weeks. Finally I decided I was going to try it. Worst that would happen is I might destroy a couple of old, obsolete thumb drives...

After a little time at the local Hobby store and discussions with the cute little salesgirl, I decided on the supplies I needed. A little experimenting and I got the technique down.

Step 1: Supplies

Picture of Supplies

First I needed casting material. I could have used plaster or latex. Plaster would produce a very porous and hard mold and would likely only give me one casting. Liquid latex would give me a nice, permanent mold but would take way too much time and work by building the casting in layers. Besides, the latex would very much irritate my thumb.

What I finally decided on was a product called "instaMOLD" made by Activa Products, Inc. ($10.50US), a water based compound that would firm up in minutes and would be reusable a few times. The problem is, would it work with plastics? What kind of plastic should I use?

Searching the plastic compounds at the hobby store proved fruitless. All of them would harden too hard for what I wanted or were way too expensive. Finally it occurred to me that most of them were some form of epoxy. Why not use regular epoxy? Studying the different epoxies that were available I concluded that the longer setting epoxy would produce the more flexible result, so 12 or 30 minute epoxy would probably be my best choices. Besides, I'd want to color the epoxy before pouring it in the mold and less that 12 minutes would probably be pushing it. This time, I'm working with the 12 Minute Epoxy ($9.95US).

Lastly, I needed color... Flesh is actually kind of easy to mix. Just Pink and Yellow. Having no idea how well they would work I bought 2 bottles of Delta brand Candle & Soap Colors for $13.99US each. Note that because the colors are water-based, they will have an adverse reaction to the epoxy mixture. The epoxy won't firm up quite as hard as it would have, so we must use as little color as will produce the desired result. For my first color experiment, I used 6 drops of pink, 12 drops of yellow and a teaspoon each resin and hardener. The result was still too pink (need more yellow) and was a little too soft (actually eerily close to real skin & muscle!). I've decided that I will be using 6 drops of pink and 18 drops of yellow for the full casting (about 3 tablespoons of epoxy mix). We'll see how well it works by the end of this instructable! :)

Oh yea! We still need the USB drives don't we? Well, I've currently got two without cases and a few more that can easily become case-less. That should be enough to start with...

Finally, we need a few small dixie cups, stirring sticks and measuring spoons. The dixie cups I used were the perfect size to cast my thumb and mix the epoxy. Disposable containers always make a project like this easier. Less cleanup!

Step 2: Make the Mold

Picture of Make the Mold

In a separate bowl, mix 4 tablespoons water with 4 tablespoons of Mold Compound. Gradually add the compound to the water as you quickly stir. This is to avoid lumps. Fully mix it together, but don't take too long. Pour the compound into a dixie cup. You will need a spoon to get it all. Tap out any bubbles and insert your thumb. You have to act quickly here since the compound sets completely in 2 to 3 minutes. Now... DON'T MOVE YOUR THUMB! Hold still for a couple of minutes. This shouldn't be too difficult.

It's important to decide the amount of compound needed before starting. You can't add more later. Starting with more water will extend the setting time, but will result in a less strong mold. I know the epoxy works well in a 50-50 mix. I might want to make more than one too. So I'll stick with what works.

Sorry, a couple of pictures didn't come out. Namely those showing pouring the compound into the Dixie cup. I think you can figure that out though.

Step 3: Casting Is Set.

Picture of Casting Is Set.

After holding your thumb still for a few minutes, carefully pull the edges of the compound away from your skin. It it seperates easily, your ready.

Pull it away all around your thumb and then carefully rock your thumb to release from the compound. It should pull out cleanly.

Step 4: Mark the Epoxy Cup

Picture of Mark the Epoxy Cup

Now my thumb is just over two tablespoons in area. With the drive, all I need is two tablespoons of epoxy.

Prior to mixing the epoxy, measure a tablespoon of water into a Dixie cup and mark the line of the water. Add another tablespoon of water and mark it again. This will allow us to accurately measure our epoxy and hardener. Empty the cup and dry it out with a paper towel.

Step 5: Prepare the USB Drives

Picture of Prepare the USB Drives

If you haven't already, plug your USB drive into a USB port and mark the connector with a felt tip pen to indicate where it plugs to. We want our thumb to be close to this mark.

Step 6: Mix the Colors

Picture of Mix the Colors

Epoxy must be mixed exactly 50/50. Using 12 Minute Epoxy gives us plenty of time to work.

Pour the epoxy resin into the cup to the first line. Here is where we add the colors. I used 5 drops of pink and 12 drops of yellow. While this didn't produce a perfect skin tone, it looks pretty good.

Stir this into the resin until it's thoroughly blended. Then tap out the bubbles. Trust me, we'll be adding enough bubbles when we mix the epoxy. We want to get as much out now as we can.

Step 7: Add the Hardener.

Picture of Add the Hardener.

Now our in the epoxy hardener to the second line. Mix thoroughly. Don't be too concerned with the bubbles. We've got 12 minutes from this point to work with it. Make sure that all the resin on the bottom is mixed with the hardener. Once you've got it mixed well, tap it a number of times on the table to knock out as many bubbles as you can.

Step 8: Pour the Mold!

Picture of Pour the Mold!

Now we pour the mixed epoxy into the mold. If you didn't measure your own thumb right, you may not have enough. Remember, it's better to have to much than not enough. The stuff's cheap!

Step 9: Wait! Then Insert Your USB Drive.

Picture of Wait! Then Insert Your USB Drive.

Wait until the epoxy starts to cure. Feel the cup. If it's starting to get quite warm, it's ready.

Carefully insert the USB Drive to just before the line and hold it steady until firm. If you've got the patience of Job (Not the Mac guy), this should be fine. Otherwise use a Stationary clip!

This was a last minute solution. Thank goodness my wife knew just where one was! Just attach the clip to just past the felt marker line and let it hold the USB drive still.

Step 10: Wait Again. Then Remove From the Mold.

Picture of Wait Again. Then Remove From the Mold.

Wait again. Let it sit at least 15-20 minutes. Longer won't hurt anything.

Check to see if it's ready. The epoxy should be dry. Not even tacky. Pull the mold compound away from the casting. If it opens a gap it should be ready. Use the very same technique of removing the drive as you did your own thumb. If you have no plans to reuse the casting, don't worry about it. Just yank! :)

Now you may want to carefully clean any compound still on the drive. Use a soft toothbrush and water. Don't scrub too hard! It's still not fully cured!

I discovered that epoxy is quite cruel to this molding compound. It's probably because of all the water in the compound. It you compare my first cast to the second, you can see that there are many more flaws in the second cast. These should be easy enough to clean off once the epoxy is fully cured.

Since we did add a water based material into the epoxy, it's going to take a bit longer to fully cure. Let it set at least 2 days before you clean the final product. Use an Exacto Knife, Razer Blades, Diagonal Cutters, what have you to trim any warts, threads, cancerous growths. A Dremel works nicely for final touch-ups.


Newell_Jalynn (author)2014-01-04


landongaga (author)2012-03-25

eww thats odd

tmyler (author)2011-10-07

Will 118ml of liquid latex be enough to mold my thumb????

GENERALCHAOS (author)2011-09-26

well il give this 2 thumbs up ...........0.o

~Z~ (author)2011-07-19

You want a real thumb drive?:

LasVegas (author)~Z~2011-07-20

Great idea, but I refuse to cut off my thumb to make this that much cuter... :)

krazumcc (author)2011-07-16

looks great unfinished almost like it was made from a finger u found ur pet dog chewing on, which just makes it even more freaky

M4industries (author)2010-02-07

 Dont use that kind of epoxy with the solvent based hardener. I recommend dragonskin.

sorry to break this to you but... dragons aren't real...

shyamiko (author)2009-05-19

Here's one I did after seeing the picture for this.... i did it with a old gag severed finger, I cut the end off down to thumb size and stuck the thumb drive into it after stripping the case. i hot glued the top where the USB part is, but it was messy so after layering it a bit I painted it red to give a nice, clean, bloody effect. :)

shyamiko (author)shyamiko2009-05-19

*The Pics*
Comments on them are welcome _

Jameszou (author)shyamiko2011-07-08

oh,cool that's great!

Coolboyme (author)shyamiko2010-03-22

cool! but.........dont you think its a bit too pink?

shyamiko (author)Coolboyme2010-06-03

Yeah x) It's supposed to be 'bloody', but whatever.

GreyGhost2 (author)shyamiko2010-03-13

 Well done, inspirational.  I need to give this ago.

LasVegas (author)shyamiko2009-05-19

Looks great! Nice and gory! Good job. :) LasVegas

fair1 (author)2011-07-07


Mirror Mage (author)2011-06-07

So that's why their called Thumb Drives.

Exitao (author)2010-03-21

I guess it's nice to have your own thumb, but the easiest way to get the "thumb" would be to go to a magic shop and ask for a "thumb tip."

Considering the time and expense in moulding your thumb, it might be easier...

GreyGhost2 (author)2010-03-13

 Hey um...whats up with scars on your right hand?... motorbiking??  Fist fight??  lol

Not that i am prying!! at all....

poofrabbit (author)2009-04-11

I simply adore this! I'm a magician and I'm sharing it with my magical friends, I have a feeling they will go nuts! VERY well done!!!

Flumpkins (author)2009-02-27

Hey! Stop biting you finger nail drives,

QwertyuioLP (author)2009-02-25

I'm going to make a hand usb hub were all of the fingers on it are usbs!

dragonblue80 (author)2009-01-04

I'm glad i'm not a cannibal.

mage (author)2008-12-06

interesting. disturbing yet interesting

Vidar_76 (author)2008-12-06

Interesting idea! Is there any way to get less bubbles in the mold? Tried a commercial kit (Clone-a-willy) a year ago and it got i lot smoother. Maybe a different kind of plastic?

desel3 (author)2008-11-25

you could just use a fake Halloween finger

mitchell931993 (author)2008-11-18

What u might wanna do is cut a piece of plastisc to the apparent shape of the your thumb- as if cutting ur thumb in half, that way rather then yanking ur fingerout and ruining the mould u can slide the whole thing from the cup and just separate it from ur finger.

oh yeah and maybe get a fake finger nail from the beauticians or something and cut and buff it with your dremel

Andrew546 (author)2007-02-23

now you need to create an "all thumbs" USB hub in the form of a hand with only thumbs. Or mold your fingers and you hand, put the drives in the fingers, and make the palm the hub.

RoKuS (author)Andrew5462008-10-10

I like the epoxy mold idea. I found this in Instructables for making a "knob" for the stick shift in your car. Maybe a mod to make a closed fist mouse??? Yeah, and "Hand Hub" would be cool!
gawd, a real thumb drive....... luv it!

LasVegas (author)Andrew5462007-02-23

Hehehe... You know... I actually thought of that! lol

Sir Camm (author)2008-08-24

pure awesome. Do you think it's possible to layer it with different colors like jello? Say, a skin shade outer shell with a little disc of red at the end where the drive connects?

MisterMissanthrope (author)2008-07-02

frikin awesome!

LasVegas (author)2007-04-06


I collect monkey wrenches... will that do?

Tomkatt (author)2007-04-20

Dude! Just buy a thumb tip from a magic shop, take the casing off a drive and fill the thumb tip with some kind of filler, far far far simpler!

yep,and probably less interesting of an inst'able as well to use something pre-made like that. this one is traceable from your fingerprint though, would that be a 'bug' or a 'feature' I wonder? these thumb drives are nicew visual puns

LasVegas shows us how to make it more personal, like others have posted it also is identifiable through the casting of one's thumb or any other finger print. Great job LasVegas!

LasVegas (author)Tomkatt2007-04-20

But not near as entertaining.

!Andrew_Modder! (author)2007-07-05

lol you can also put one of tho's fake finger nails on it to make it look more real! :-D

LasVegas (author)!Andrew_Modder!2007-07-05

I thought of that. Unfortunately, the largest size artificial nail I could find was a -1 (minus 1) and it was too small. I was going to trim the nail and fit it into the mold before pouring the epoxy. I'm sure it would have looked great had I been able to find a big enough nail.

Gage987 (author)LasVegas2008-06-18

get a fake finger nail like for girls and do some work

!Andrew_Modder! (author)LasVegas2007-07-06

yeah, i was fearing they might be to small, lol mabe cast a plastic 1 :-)

Gage987 (author)2008-06-18

those make me wanna puke not to be mean but they look gross

struckbyanarrow (author)2008-04-03

Cut your fingernails! sicko!!!!!

Valche (author)2008-04-01

A little goss, but well done and funny!

amadoraa123 (author)2008-03-02

thats.. kind of distrubing.. but awesome... im gunna try this.. ive been looking for something to "jazz" up my umm.. thumb drive.

Shifrin (author)2008-01-05

Ha! This is so cool, This is probably the coolest Thumb Drive Case i've seen yet! Well Done! ~Shifrin

Mitten (author)2007-04-28

I'd paint some lacquer or varnish on the nail to make it appear "thick" or shiny.

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