Posted 09.22.2009 at 4:47 pm
15 Comments
Ferrofluid: Andrew Magill
There are many commercial applications for ferrofluids--speakers and hard drives being the most common. The oily fluid prevents debris from entering hard drives when a small amount is placed between the magnets and shaft. In the case of speakers ferrofluids remove heat from the voice coils and help dampen the cone movement. My own interest in the black ooze is a desire to create custom cases for electronics. And even more fun can be had making dynamic molds by pouring a hardening agent over the fluids.
If you are still wondering what ferrofluids are take a look at this video:
DIY Option 1: Magnetic Ink Developer
Ricoh 410 MICR Developer: prank via Instructables
DIY Option 2: Ferric Chloride
NYC Resistor Converting Ferric Chloride: Makerbot/Flickr
The ferric chloride conversion is clever. Electronics enthusiasts often keep ferric chloride at home to eat away copper which makes a reasonable DIY circuit board. The chemistry involved seems easy enough.
- mix ferric chloride with water
- add steel wool - stir until bright green
- use a coffee filter as a strainer
- add more ferric chloride
- add ammonia
- heat for a hour at boiling (in a well ventilated space)
- let solution cool
- add kerosene
- pour off kerosene discard water
DIY Option 3: Recycling Audio Cassettes
Cassette tapes ready for acetone: Zujus via Instructables
Finally, we have what looks like the most DIY approach--acetone to extract the iron particles from old casette tapes. Obtaining tapes and using acetone is labor intensive, but commendable.
Controlling the shape of ferrofluids and then "freezing" them in place could be another tool for inexpensive desktop fabrication. Combining two unusual uses of magnetic fluids invites further empowerment for the maker. This French nail polish has magnetic particles that can be triggered into elegant patterns after being applied and before setting up. And Martin Frey has a dynamically controlled ferrofluid art piece titled SnOil that offers 144 pixels that is a low-res display.
SnOil ferrofluid digital art: Martin Frey
I plan to try the chemical ferric chloride approach used in DIY option 2 substituting the kerosene for biodiesel and the oleic acid for citric acid. In order to get a freeze effect I will begin with pouring epoxy resin over the ferrofluid. Then observe the fluid's behavior. Can it hold a shape long enough for the resin to setup? That, we shall see.
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I spent the summer making milligram quantities of nanowires (5-25 micrometers long) for magnetorheological fluids (MRF)which is the more technical term. The lab I worked at invented MRFs with wires and spheres that stay suspended for much longer than homogenous MRFs and can be used for more sensitive applications than normal MRFs.
MRFs can be used in shock absorbers to make them an active system that can adapt to their environment. The army has done tests with humvees equipped with MRF shocks and normal shocks and the MRF equipped ones could go 20 miles an hour faster over very rough terrain with much less jarring.
i actually want to use this as a possible heat sink for my computer case.
A liquid magnet or ferrofluid is a colloidal mixture of magnetic particles (~10 nm in diameter) in a liquid carrier. The carrier contains a surfactant to prevent the particles from sticking together. Ferrofluids can be suspended in water or in an organic fluid. A typical ferrofluid is about 5% magnetic solids, 10% surfactant, and 85% carrier, by volume. One type of ferrofluid you can make uses magnetite for the magnetic particles, oleic acid as the surfactant, and kerosene as the carrier fluid to suspend the particles.
Ferrofluid is very strongly attracted to magnets, so maintain a barrier between the liquid and the magnet (e.g., sheet of glass). Avoid splashing the liquid. Both kerosene and iron are toxic, so do not ingest the ferrofluid or allow skin contact (don't stir it with a finger or play with it).
Here are some ideas for activities involving your liquid magnet ferrofluid. You can:
* Use a strong magnet to float a penny on top of the ferrofluid.
* Use magnets to drag the ferrofluid up the sides of a container.
* Bring a magnet close to the ferrofluid to see spikes form, following the lines of the magnetic field.
Explore the shapes you can form using a magnet and the ferrofluid. Store your liquid magnet away from heat and flame. If you need to dispose of your ferrofluid at some point, dispose of it the way you would dispose of kerosene. Have fun! To read more: http://personalmoneystore.com/Payday-Loans/instant-Payday-Loans/instant-...
This is so cool that it's making me salivate!
I wonder how this would act in zero gravity. Maybe we could get NASA to attempt this?
Wow that is like the coolest thing I have EVER seen!
Jess
www.online-privacy.us.tc
could you dye it other colors? say, white, or possibly get a chrome finish on it?
So this stuff should keep for virtually ever, right?
I was looking into making some a while ago, but seems a little too dangerous for my tastes. I know it's not overly risky, but the risks there are just more that I'd like to handle. I'm kind of a klutz, and it's not hard for me to see myself spilling magnetic ink developer or ferric chloride all over myself or house, and that would be very bad indeed.
Dose no one purge cancerous spam from these comments? SusanW is stealing from http://www.chem4all.vn/forums/showthread.php?t=4703 and trying to trap you in foulness.
I have had the luxury of working with ferrofluids for over 25 years. They are fascinating materials. I will say there is tremendous differences between types of ferrofluids and vendors. Ferrofluid selection requires careful consideration of the application. One other comment since someone above mentioned NASA. This material came out of NASA-funded development efforts.
BDM
Question 1: doesn't the Ferrari 599 gtb Fiorano have something like this in its active suspensions as well?
Question 2: It's cool that we can with little effort make some of this substance in the comfort of our home, but for what purpose? the appliances that need some already have it,so besides bragging rights(?) what can it be used for?
moving sculptures maybe?
Seriously, I wonder.
Thanks
from Chula Vista, CA
I am just wondering what are all of the uses this stuff has?
-Your Friend Zunigadragon
"Following the magnetic lines" suggests the question (no, duufi, not "begs"; that refers to circular reasoning. YCLIU), "Why does a magnetic field have lines?" That would seem to require/imply self-attractive particles, otherwise it would be a magnetic sheet, undifferentiated. Maybe it is until particles get involved. How would you know?
SHINEY!!!!!!
This stuff sells for $165 a liter!!! I wonder how much I can make in a week.