DIY magnetic sweeper? Grade and size of magnets

[visor_down]

Hi all
I'm after a magnetic sweeper, surprised by the price of them, so considering making one.
Anyone made one before? Any knowledge of what grade and strength of magnets are needed?
Need it to sweep gravel so it's not just going to be a flat floor and will need it to be good couple of feet wide or more.
Maybe the cost of magnets explains their relatively high cost for what is a magnet on wheels but thought it worth exploring
Cheers

 

[anjum]

I wonder why it would not use electromagnets?
So many advantages.

 

[JEZGUZ]

Golf trolley and some scrapped door magnets. Pretty sure they use low voltage to activate, no doubt someone with better knowledge will correct me if I've got it wrong.

 

[DAPPH]

Buy one of these 80 kg magnets each day so the order is kept small so as to not attract customs duties on them .
Three should allow you to work the gravel in strips if you mark the lanes out with a thin cord put the magnets on a simple axle with plastic pipe as spacers to keep them apart on the axle .

eBay item number:
283853658118
or look at this one as there are dimensions given
eBay item number:
264631054474

 

[Tom O]

I have a 18” one with 3/4” clearance that comes with a quick release they work great!
Mine came from Princess Auto.