magnetic rock

[ashley]

Does anyone know how I can make a magnetic floating rock?

 

[redfishbluefish]

Buy neodymium magnets and drill holes in the rock using a masonry bit that will easily fit the magnet. Coat the magnet in epoxy and put it in the hole. Let cure. Us a second magnet on the outside of the tank per in-tank magnet. I'd coat that magnet in epoxy as well.