Definitely the most creative use of ferrofluid I've seen for a long time. However I fear that long term you might have problems with the ferrofluid separating,

Definitely the most creative use of ferrofluid I've seen for a long time. However I fear that long term you might have problems with the ferrofluid separating, emulsifying or oxidizing. It would be interesting if we got updates on how it holds up after a few weeks or months of use.