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Magnet Fishing II

Our newest magnet fishing designs!

In our previous Magnet Fishing and Relic Hunting articles, we explored the popular hobby of Magnet Fishing. In those articles, we used some of our regular Mounting Magnets, tied off to a rope. Now, we have a brand new line of magnet fishing magnets! In this article, we'll highlight and test these new products. 

Quick overview - What's magnet fishing again?

Magnet fishing uses a strong magnet to try and grab ferrous objects that are at the bottom of lakes, rivers, ponds, etc. A strong magnet is tied off to a rope, thrown into the water, and pulled along the bottom to try and "catch" some hidden treasure. 

There are plenty of magnet fishing videos online, showing all sorts of treasures found - from lost phones and wallets to old war relics! The possibilities of what you might find are endless. See K&J's magnet fishing adventures here and here

New magnet fishing magnets!

We now have 6 awesome fishing magnets in stock, 2 different styles in 3 different sizes/strengths. Our FM1 style has a beefy eye bolt on the top, while the FM2 style has the same eye bolt on the side, to allow for a double-sided fishing magnet - they all come with lock washers, though it couldn't hurt to add some thread-lock as well. 

These 3 sizes have 3 different strengths, 230lb, 400lb and 500lb! The double sided fishing magnets have that amount of pull force per side. We designed these magnets to have a thicker steel cup compared to our normal mounting magnets, which provides an increase in strength and allows for the eye bolt to be threaded deeper into the cup.

How much weight can these pick up?

The answer varies. The pull force we list assumes the magnet is attracting to a large, flat, dry, steel plate. It is the force required to pull the magnet straight off the steel plate. Another way to look at it would be if you put the FM1-48 to an overhead I-Beam, you could hang 230lb straight down from it before it broke loose. 

The pull force you "get" from a magnet depends on the object it's attracting to, and how far apart the magnet and object are. The pull force would be less to a smaller ferrous object. The pull force would also be less if there was something between the magnet and the object, like a layer of mud. 


FM1-48 attracting to a steel wrench

Let's do some testing to see how the pull force numbers actually translate to a  real world application. In magnet fishing, you'll probably never be directly attracting to a nice large, flat, dry piece of steel, and pulling straight on the magnet. 

First, we'll do some pull force testing to three different objects, a wrench, steel rod, and a thin piece of sheet steel (think old license plate). Below are the results. 

MagnetListed PFSteel RodThin SteelWrench
FM1-48230 lb24.2 lb10.2 lb57.2 lb
FM1-60400 lb28.4 lb11.8 lb43.8 lb
FM1-75500 lb30.8 lb12.2 lb44.8 lb

Wait a second, the FM1-48 has a stronger pull force to the wrench than the other two magnets? It does seem strange, we were surprised to see this and triple-checked our numbers. However, magnetically, it is explainable. The field of these mounting magnets is extremely strong at the edges, more-so than the middle of the magnet. Since the FM1-48 is a bit smaller in diameter, more of the edge is on or close to the wrench, compared to the larger magnets. 

Magnetic field of a disc magnet compared to a Mounting Magnet.  Magnet shown in green.

How would these numbers decrease if there was a gap between the magnet and the object? Let's look at the FM1-48 attracting to the wrench. If the two were separated by a gap of 1/16", the pull force decreases to around 18 lb. Keep this in mind if the area you are fishing has a lot of muck and mud!

Next, let's test out the double-sided fishing magnets. Since they don't have a hook in a position that would allow you to pull straight away from the magnet face, how much force would it take to leverage them off of a steel plate? What about slide them along a steel plate?

MagnetListed PFLeverageSlide
FM2-48230 lb53.8 lb47.6 lb
FM2-60400 lb93.6 lb82.8 lb
FM2-75500 lb117 lb103.5 lb

A FM2-48 being leveraged off
Sliding the FM2-48 on a steel plate

Final Thoughts

There is some balance between wanting a very strong pull force and getting the best bang for your buck. We are often asked if we could supply a 1,000 lb fishing magnet. While it might be feasible, is it worth the extra money? Seeing how a smaller, less expensive magnet has similar pull forces when attracting to smaller ferrous objects, it might change your buying decision. Plus, if that 1,000 lb fishing magnet did get stuck to a sunken I-Beam, or an old boat, good luck getting it off!

Don't try this at home!

In an effort to showcase how strong these magnets are, here are some miscellaneous objects being picked up by our fishing magnets...imagine "catching" stuff like this in your local river!

A FM1-48 picking up a heavy steel cart!
Close-up of the FM1-48 on the cart
A FM1-60 picking up a full-size filing cabinet
Close-up of the FM1-60 on the filing cabinet

300lb worth of steel and chain
Hanging 300lb from the FM1-60!

500lb of K&J employees is no match for two FM1-75
Two FM1-75 securely holding 500lb of magnet nerds

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