Ferrofluid failure

Friday 5th August 2016

If you love a bit of schadenfreude then you'll enjoy this week's post where one of my projects goes completely wrong. I've been thinking a lot about the way we present ourselves to the world, and I decided it was important to show that my life has a lot of fails just like everyone else's. 

Making ferrofluid

I wanted to get hold of some ferrofluid, a beautiful magnetic liquid. It's quite pricey on eBay, about £10 for 20mL, so I found a tutorial that shows how to make it out of acetone and old tape cassettes.

So far so good.

I bought some acetone from eBay (£6.95) and found my last remaining ten cassettes, mostly mix tapes that I'd made during the 90s and couldn't bear to throw away. Making something awesome from their remains seemed like a fitting end.

The first step was to smash the cassettes up and place the tape in a kilner jar, then fill it with acetone and leave for a few days for the solvent to dissolve the tiny iron particles off the plastic tape.

I left it a week just to make sure, then poured the brown liquid into a bowl and let it settle. 

The settling process took quite a while because the particles were so fine, but I discovered that by putting a strong magnet on the outside of the jar I could speed the process up massively - it cleared in just a few minutes and produced some beautiful patterns, below. They moved ever so slowly, like magnetic urchins.

Once the iron particles had settled out, I poured the almost-clean acetone back in the bottle and left the brown goop outside so the rest of the acetone evaporated. It became quite hard and lumpy, like a metallic cat poo.

Once the actone had completely evaporated, I added a little vegetable oil and voila!

Oh. That's not what it's supposed to look like.

I did some more research and found out that the particles on magnetic tape are far too large to work as a ferrofluid.

They're around 500nm across, which is awfully small, but ferrofluid particles need to be 10nm - fifty times smaller. So the goop went in the bin and I bought some ferrofluid from eBay, which I'll write up shortly.


I've always joked that we need a separate version of Facebook called Failbook where everyone posts photos of their average days, talk about arguments with their partners and how they feel generally unsatisfied with life.

Obviously no-one has the life that they portray on social media but it's easy to forget that when you see their perfectly curated exhibitions and compare them to your own. I'm just as consumed with self-doubt, worry and paranoia as you are, and I don't think it helps to hide it.

In eighty posts for this site I've only ever mentioned failing twice, once when I nearly ruined our front door with a jigsaw and once when a batch of charcoal caught fire while it was cooling down. 

In reality, almost all of the posts I've ever written have involved some kind of failure, but I've omitted them without evening considering it.

When we made cola I pretty much wrecked our food processor with the plastic-eating essential oils. When I made salt from seawater I took the Teflon coating off an expensive frying pan because I was too impatient to wait for it to evaporate. When I learned to make lace I lost count of the number of times I had to unpick it and start again because I had trouble learning the motor skills, and I melted a set of plastic petri dishes for the licky experiment by trying to sterilise them in steam. 

My point is that it's completely normal to fail repeatedly, and you only need to succeed once to make it work.

So in future posts I'm going to be more honest about when it goes wrong!



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