Magnet set

[Simon P]

Hi All can anyone recommend a good magnet set for general use please?

Looking for something that’s good value and works well. Not looking to go magnet fishing!

Just after something that will retrieve dropped metallic items from the canal.

Theres a lot of choice and diffo Kgs ratings. Don’t know what is good or bad.

Many thanks

[Peugeot 106]

I’ve got a Sea Searcher. It’s pulled out windlass, mooring and nappy pins in it’s time and I’m happy with it.

[Simon P]

👍will Google that. Cheers 

[MtB]

The stronger the better. Remember, the attraction to the magnet falls with the square of the distance. So to actually grab something dropped into the cut, you'll have to drag the magnet past surprisingly close to the target object to get it.

 

My best advice though is don't drop stuff in the water in the first place. Especially not ropes. 

[David Mack]

Sea Searchers are expensive. I just bought a cheap magnet with a ring on  it from ebay  and it has proved fine at retrieving things like the steel end of my short shaft. Not much use on an aluminium Dunton Double though.☹️

[rusty69]

Sounds like a thread for @magnetman

[magnetman]

These days I would probably just go for a pot magnet maybe something with 50kg rating. If you get something too big it sticks to the boat and you end up pulling out mountains of scrap. 

 

Its been over ten yars since I dipped a magnet. 

 

 

[Jen-in-Wellies]

Sea Searchers were good value for what you got fifteen years ago. I have one. It gets used very very occasionally. There are now lots of cheaper 50 to 60kg force rare earth magnets around that will do the job of a Sea Searcher for a fraction of the price. I believe Sea Searcher are largely trading on their brand recognition these days to justify the marine markup.

[magnetman]

10 minutes ago, Jen-in-Wellies said:

Sea Searchers were good value for what you got fifteen years ago. I have one. It gets used very very occasionally. There are now lots of cheaper 50 to 60kg force rare earth magnets around that will do the job of a Sea Searcher for a fraction of the price. I believe Sea Searcher are largely trading on their brand recognition these days to justify the marine markup.

When I was making and selling the little Maxigrab magnets it was impressive how much stronger they were than the Sea Searcher. Ten times the power basically in size terms. 

 

This was about 15 yars ago and since then a lot of cheap and cheerful chinese products have turned up (all the magnets do come from china anyway). 

 

The bigger ones are so powerful they will actually completely demagnetise a Sea Searcher and render it completely useless. SS use Strontium Ferrite magnets which are crap compared with NIB magnets. 

 

The giveaway with Sea Searcher advertising is they show one lifting a 13kg calor gas bottle in a video. 

 

Why would you need a magnet to recover something which is floating ??

[Nightwatch]

I bought one off Amazon a few months ago. To see how strong it is I stuck it on the boat side. Honestly I couldn’t get the Bloomin thing off without a load of wrestling with it. I’ll try and find a link to the sale.

Couldn’t find the one I bought but just search ‘strong magnet’. Loads come up. The sea magnet seems popular.

[David Schweizer]

17 minutes ago, Nightwatch said:

I bought one off Amazon a few months ago. To see how strong it is I stuck it on the boat side. Honestly I couldn’t get the Bloomin thing off without a load of wrestling with it. I’ll try and find a link to the sale.

Couldn’t find the one I bought but just search ‘strong magnet’. Loads come up. The sea magnet seems popular.

The easiest way to avoid a sea searcher attaching itself to the side of the boat is to slip a thin plank of wood down the side of the hull before lowering the magnet into the water.

[IanD]

1 hour ago, Nightwatch said:

I bought one off Amazon a few months ago. To see how strong it is I stuck it on the boat side. Honestly I couldn’t get the Bloomin thing off without a load of wrestling with it. I’ll try and find a link to the sale.

Couldn’t find the one I bought but just search ‘strong magnet’. Loads come up. The sea magnet seems popular.

 

Seriously, some of the newer neodymium magnets off eBay are *ludicrously* powerful, watch out for your fingertips as well as getting them irremovably stuck to the hull...

Edited June 26, 2023 by IanD

[Nightwatch]

7 minutes ago, IanD said:

 

Seriously, some of the newer neodymium magnets off eBay are *ludicrously* powerful, watch out for your fingertips as well as getting them irremovably stuck to the hull...

True.

[Jen-in-Wellies]

9 minutes ago, IanD said:

 

Seriously, some of the newer neodymium magnets off eBay are *ludicrously* powerful, watch out for your fingertips as well as getting them irremovably stuck to the hull...

That's given me an idea. Neodymium based blacking. 😀

[magnetman]

15 minutes ago, IanD said:

 

Seriously, some of the newer neodymium magnets off eBay are *ludicrously* powerful, watch out for your fingertips as well as getting them irremovably stuck to the hull...

When I bought a 76mm Diameter x 50mm thick N52 neo disc magnet in 2007 the man on the phone did a lot of elfin safety warnings about it. Crushed hands etc. It was a magnet made for separators in food production lines rather than a consumer product. £180 for the magnet. 

 

It is still ridiculously strong. Got a heck of a lot of stuff out with that magnet. I put it in a cut down 76mm brass shell casing to protect the magnet and a big eye bolt. 

 

 

Neodymium magnets are mental. 

 

This was well before they became common. 

I did have a 5 inch diameter 2 inch thick disc but didn't fancy it so gave it away. The bloke I gave it to took it out of the box and offered it to a radiator. It clamped on and shattered. I think he remembers this incident. 

 

Too much power there..

[IanD]

1 minute ago, magnetman said:

When I bought a 76mm Diameter x 50mm thick N52 neo disc magnet in 2007 the man on the phone did a lot of elfin safety warnings about it. Crushed hands etc. It was a magnet made for separators in food production lines rather than a consumer product. £180 for the magnet. 

 

It is still ridiculously strong. Got a heck of a lot of stuff out with that magnet. I put it in a cut down 76mm brass shell casing to protect the magnet and a big eye bolt. 

 

 

Neodymium magnets are mental. 

 

This was well before they became common. 

 

The magnets intended for eyebolt fixing to metal surfaces (and often sold for magnet fishing) usually have a steel return yoke around the neo magnet core to bring both poles to one surface, this magnifies the pull by many time compared to a bare disc magnet with the two poles on opposite faces. This means less (expensive) neo is needed, but makes them even more dangerous of something like a finger gets trapped in a closing gap... 😞

 

Not just being elf'n'safety paranoid here, but anyone waving one around near a big steel thing is just asking for trouble, especially if when it swings towards the hull you do the instinctive thing of trying to grab it to stop it locking on. Take care... 😉

 

(when I did a lot of electronics assembly you could always tell the experienced solderers from the newbies by the different reaction if a soldering iron got knocked off a bench -- both hands up in the air = experienced...)

[TheBiscuits]

9 minutes ago, IanD said:

(when I did a lot of electronics assembly you could always tell the experienced solderers from the newbies by the different reaction if a soldering iron got knocked off a bench -- both hands up in the air = experienced...)

 

 

Remember this one?

 

[magnetman]

23 minutes ago, IanD said:

 

The magnets intended for eyebolt fixing to metal surfaces (and often sold for magnet fishing) usually have a steel return yoke around the neo magnet core to bring both poles to one surface, this magnifies the pull by many time compared to a bare disc magnet with the two poles on opposite faces. 

This is okay if you want to pick up light objects but having done experiments I found that if you want to pick up heavy things (like the pickaxe lifted from the pointed end) you do actually want to have thickness of magnet. For clamping purposes on clean material a steel encased magnet is good but for getting random old rusty objects out sometimes buried in mud there is no substitute for thickness.

 

The penetration is better with a thicker magnet. 

 

 

 

Air gap penetration is important here. 

Your 76mm diameter thin disc in a steel pot won't have the same air gap penetration performance as my 76mm x 50mm disc in a brass casing. 

 

 

 

It may have a higher clamping force on a flat steel surface but this is a useless measure because things one drops in very rarely have flat clean surfaces. 

[IanD]

21 minutes ago, TheBiscuits said:

 

 

Remember this one?

 

Yeah... 😞

[magnetman]

My 76mm disc magnet has a central hole so I secured it to the shell casing with a coachbolt which provides a protrusion and makes it impossible for it to clamp onto a flat surface such as the side of the boat. Other end of coachbolt has an eyenut screwed onto it with loctite. 

 

 

[IanD]

12 minutes ago, magnetman said:

This is okay if you want to pick up light objects but having done experiments I found that if you want to pick up heavy things (like the pickaxe lifted from the pointed end) you do actually want to have thickness of magnet. For clamping purposes on clean material a steel encased magnet is good but for getting random old rusty objects out sometimes buried in mud there is no substitute for thickness.

 

The penetration is better with a thicker magnet. 

 

Air gap penetration is important here. 

Your 76mm diameter thin disc in a steel pot won't have the same air gap penetration performance as my 76mm x 50mm disc in a brass casing. 

 

That's true, the pot gives more field close to the gap but less further away.

 

I wasn't saying that the enclosed ones were *better* for magnet fishing, just that this is how most are sold because they can claim a high kg rating with much less neo. And the massive close-in field means they're even worse for snipping off fingertips than an "open" one like yours...

 

Here's another tip learned the hard way through building PA speakers -- before doing anything with these magnets, take your wallet with any credit cards in it out of your trouser pocket and place on a shelf. DAMHIK... 😞

Edited June 26, 2023 by IanD

[magnetman]

It is just pot magnets they use for hanging supermarket adverts from the rafters being sold as recovery magnets. 

 

Yes they are dangerous. When I was selling magnets I specifically steered clear of that type.

 

 

 

 

  

   

[cuthound]

3 hours ago, Nightwatch said:

I bought one off Amazon a few months ago. To see how strong it is I stuck it on the boat side. Honestly I couldn’t get the Bloomin thing off without a load of wrestling with it. I’ll try and find a link to the sale.

Couldn’t find the one I bought but just search ‘strong magnet’. Loads come up. The sea magnet seems popular.

 

The first magnet I had found me.

 

I was on my first shareboat and as I entered the lock the boat started making a clanging sound in time to the engine.

 

I bowhauled the boat out and found a load of blue rope wrapped around the prop. The end seemed to be stuck so I pulled harder and nearly did a backward somersault onto the towpath as the magnet freed itself from the bottom of my boat.

[rusty69]

Just now, cuthound said:

 

The first magnet I had found me.

Love at frst sight? A mutual attraction!

[cuthound]

1 hour ago, Jen-in-Wellies said:

That's given me an idea. Neodymium based blacking. 😀

 

Nah, the boat wouldn't be powerful enough to break the attraction to the piling... 😅