My instructable is based on the 'less is more' philosophy. Excuse the camera, but it should be straightforward and logical.
Step 1: Silicone Mixing Compounds
There is enough material to make 200-300 molds. You don't need that much material, but you will need a lot for all the mis molds you will make.
Depending on your ear size, you want to make 2 small balls of each compound. The amount of compound you will need will vary with the size of the holes in your head, however, if each ball is the size if a small marble, it is too much.
You want the each of the balls to be the size of a pea. It doesn't matter if the balls aren't exactly the same size, close is enough.
Step 2: Finding an Appropriate Earbud
There are various types of earbuds out there, and it is important to find one that will work for your ear size.
I have happened to luck out with a good brand of earbuds called Comply in the Ear NR-1's. The sound quality is average, great for audiobooks, and ok for music, but the important thing with these earbuds is the fact that part of the construction includes a tube shaped appendage that holds onto the soft foam tips that insert into the ear. This particular model is great because it completely blocks out all exterior noise to make listening more enjoyable and at lower volumes.
Also on the plus side is that this model with a little work is completely rebuildable with a little know how. The headphone jack and earbud wires have long since frayed and shorted out, and with a little work I've been able to graft these earbuds with new hardware.
FYI, the best wires I've found so far are these :
The plugs will fail eventually, but the wires are strong, robust, don't tangle, and have a nice rubbery texture. Also, they don't harden over time which is a huge pet peeve of mine. The internal wires are high quality and will last much longer than dollar store headphones.
The main inspiration for the build is the fact that the soft foam gets gungy over time and loses it's elasticity.
To prep for the build, I removed the foam eartip, cut away the foam from the rubber core, and screwed the remaning bud (black in picture) back onto the tube.
Now the earbud is ready for the molding process.
Step 3: Mix and Go!
The silicone material has a 5 minute set time so you have to work fast.
Mold the two compounds together and shape into a cone shaped ball.
Work as much material as you can into your ear canal. Plug your nose and swallow and move your jaw to try to draw it into your ear
Don't worry, unless you screw up really bad you will not lose this material in your ear.
If you feel like you've screwed up and put it too far into your ear just wait 5 minutes for the material to set, then pull out the material and start again.
Whatever you do, DON'T push the material into your ear and while still soft wipe away the material outside of your ear leaving material just inside your ear. You need a flange of material outside of the ear canal to be able to grab onto to pull out.
If you don't have anything to grab onto, don't panic. The material is still reasonably soft so you can still hook it out with a sharp needle or dental tool if you should have one so handy.
While the material is still soft, push the earphone into the material and try to approximate a good tunnel path that you think that sound will follow.
As the material sets, keep pushing the earbud into your ear. You will hear the material curing and setting. Keep firm pressure on the earbud pushing into the material. If you don't push, the material will slowly push out of your ear. After about 5 minutes, you will find that the material has cured sufficiently. If you want to be 100% sure, just wait until you don't hear the curing anymore.
Step 4: You Will Make Many Mistakes
On my first try for this build you will see that you can see the black base of the earbud. This is bad, this means that the earbud is resting on the side of the ear canal and not in the middle of the material.
On subsequent tries, you will see that the earbud is centered perfectly in the middle of the earcanal and surrounded by silicone.
If you have a friend to help you as you lie on your side, they will be better able to insert at the right angle and location.
Step 5: Finishing of the Mold
Get yourself a drill with a drill bit and follow from the tip from the inside of your ear back to the outside where the earbud was inserted.
Make sure that where the drill bit tip intersects with the negative mold of the earbud is where the sound exits from the earbud and not the side. If you don't then the sound will not have a path to travel to the eardrum.
Make sure that you don't mess up the mold from the earbud when you are cleaning out the excess silicone material. You want a snug fit so that the earbud will not fall out inadvertently.
If you are having fitting problems, if you are finding that your new tip is falling out of your ear, you can wet it with a little saliva before you insert it, or you can clean your ears.
If that fails, you can take an emery board and lightly file some of the material off. Be sure to file more from the base and not from the tip. This will ensure that the sealing is still good and help pull the mold into the ear. If you sand the tip too much, what will happen is that the sealing will not be good and will also push the tip out
Step 6: Insert Into Ear
The rubbery texture of the silicone will hold the earbud in and if the cord is accidentally yanked the earbud will easily pop out saving your wires.
The earbuds will easily pop back in.
Over time the tip will get dirty. Lots of water will clean the material to 100% new.
If you've made a good set of tips, you will find that they completely seal the ear from outside noise and should be comfortable to wear for hours. I've even worn them for 24 hours with no problem. The material moves and bends with the movement in your ear canal but there is not pressure fatigue like there is with expanding earplugs or even the silicone flanges from some earbuds.
Once molded, the material will not shrink or change shape, but will still have a soft texture. Unlike a foam eartip, this tip will not need to be compressed to put into your ear. Simply wet it and slide directly into your ear. When they get dirty, simply rinse under water with soap if you wish.
The tips hold the earbuds snugly so that I can put on a helmet to ride my motorcycle without them falling off, and I can ride with music at a comfortable level.
Walking around the city they just look like any other earbud, except that that the sound clarity is great, and the noise from surrounding people, the bus and traffic is greatly reduced.