This is something that many people have asked, but only a couple have found the answer and refuse to share it. Today, I'm going to share with you what worked well for me in making my own ferrofluid display.
A glass jar with a screw-top lid, preferably any shape but cylindrical (Some glass has small impurities and the fluid will stick to the jar no matter what fluid you use, keep this in mind when picking the jar you want to use. The smoother the better.)
What you'll need:
$1.09 Distilled water (I used poland spring, but any brand should work)
$3.99 Sugar (100% cane sugar, or sucrose)
$15-$30 The ferrofluid itself (I used Ferotec EFH1)
$3 And a magnet to play with it
How to put it together:
First, if the jar has been used for anything else, clean it well with soap, water, and some elbow grease. For example, I made one out of an old olive oil jar, and there was TONS of residue from the oil still in the jar which would have interfered with the whole thing.
Second, you're going to want to scoop some sugar into the jar. I made an 8 oz display, and ended up using about 3 and a half spoonfuls of sugar (it sounds like allot, but trust me, it'll work!) If you're making a bigger display, the general rule is that you want to put as much sugar into the water as it will dissolve.
Now add the water, but leave a little bit of air at the top of the container. Put on the lid, and shake up the container until all the sugar is completely dissolved. If it seems like the sugar disappeared too quickly, feel free to add more. But if you add too much, dump out some of the solution and add more water. When you're done, there should be no little grains of sugar floating around in the water, and it should be completely clear.
Once the sugar is completely dissolved, add as much ferrofluid to the display as you want. In this scenario, less is more, but this is your display, I'm not the one making the decisions. It's best to keep your magnet handy, as a drop or so of the ferrofluid will float on the surface of the water until it's pulled down by the force of the magnet. Once you're happy with the amount of ferrofluid in the container, fill up the rest with water and screw on the lid as tight as you can.
Once your display is sealed off, it's ready for you to play with it! Like I said earlier, some fluid will almost inevitably get stuck to the side of the container, depending on its quality but to get most of it off you can simply run the magnet over the spot a couple times and the majority of it will drop back down to the bottom.
Links to the specific products I used:
Sugar - http://www.wegmans.com/webapp/wcs/stores/servlet/P... Any brand you can get will do just fine.
Water - http://www.wegmans.com/webapp/wcs/stores/servlet/P... Any brand you can get will do just fine.
Jar - http://packagingoptionsdirect.com/8-oz-french-squa... + http://packagingoptionsdirect.com/43-400-continuou... I also found that a glass jar I got with some syrup worked great.
In total, I spent 35 or 40 bucks for my display, including the ferrofluid. You could buy one from Vat19 with that money and not worry about the suspension fluid or the jar, but making your own not only is a great experience to just experiment with, you also get to make any size display with as much ferrofluid as you want with any shape jar to fit your preferences, let alone the joy of actually making something so awesome yourself.