Determining Needed Magnet Strength

JQuacker

New Member
Hey folks - looking at an upcoming Mass Effect Shepard build, and I'd like to try to magnetically hold the guns on my back like Shep when not in use. I see K&J has some really strong neo ones, so how can I determine the best one to use for the weight? Say the gun weighs 5 lbs (yet to be determined, just starting somewhere to get an idea of how the math would work), would something like this work? Overkill? Not enough? How do I go about knowing the math so I can adjust appropriately?
 
Personally, I wouldn't go with anything that has a pull strength of more than double the weight of the object your wanting to mount. Bare in mind that with a pull strength of say 40 pounds (as seen in the link you posted) you will have to exert 40 pounds of force to break it free. I wouldn't want to have to lift a 40 pound weight off of my back over my shoulder...
 
Sounds too difficult.:wacko
Just use a hook to take the downward gravity and to cater for the sliding forces.
Then add a magnet or two to cater for any residual upwards sliding and pull-out forces.
Depends what you are going to do....run, walk...jump with guns on your back.:confused
Use trial magnets with makeshift trial gun weights attached and see which combination
of magnets and or hooks or other methods will work best for you.
Haven't done this with magnets before so I don't speak from experience. I have only used magnets for more static display
applications.
Maybe someone can chime in who has a better idea and knowledge on this stuff.:devil
 
Personally, I wouldn't go with anything that has a pull strength of more than double the weight of the object your wanting to mount. Bare in mind that with a pull strength of say 40 pounds (as seen in the link you posted) you will have to exert 40 pounds of force to break it free. I wouldn't want to have to lift a 40 pound weight off of my back over my shoulder...

Yeah, I'm trying to mentally account for shear/sliding force also. That example magnet would be 40lbs to directly "lift" it from the steel/etc, but sliding is much less.

Sounds too difficult.:wacko
Just use a hook to take the downward gravity and to cater for the sliding forces.
Then add a magnet or two to cater for any residual upwards sliding and pull-out forces.
Depends what you are going to do....run, walk...jump with guns on your back.:confused

I like this idea. Almost a cradle, but the magnet keeps it from falling over. The cradle keeps it from sliding down. Then when I reach over and pull up, the sliding will help detach.
 
I've a full N7 female armor and some weapons. Magnets depends on the thickness of your armor. They could work but as said a lot of pull strength. And will increase the weight nevertheless, the batteries on my helmet, made it a bit heavy. Have you considered, depending on how invisible you can make it, velcro? Just a thought.

Edit. As example, https://www.tapatalk.com/groups/starfleet1701st/rubies-tos-phaser-for-costuming-t1145.html. And if using leds, need to know if the battery and magnets will work fine.
 
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I wouldn't go with a single strong magnet, at least not without experimentation. I would try a series of smaller magnets adding them until you find the right balance. Don't forget that they will have a tendency to orient the gun too, so you will need room to move them around a bit, whether it is one magnet or multiple.

I didn't calculate anything, but to securely mount them, I think the 142 lb magnet is overkill for a 5 lb item, but the 64 pound one, might be close if you want to make sure it is secure.

Good luck. I like the idea. If it can't be done with magnets, it shouldn't be done at all!
 
How about an electromagnet powered by 9 volts where the magnets are activated by a microswitch? Unsure of how much time the weapon was to remain slung, the or battery life.

TazMan2000
 
Have you considered, depending on how invisible you can make it, velcro? Just a thought.
And if using leds, need to know if the battery and magnets will work fine.

That might work for smaller ones, but I don't see a Black Widow doing well that way. And good note on batteries/magnets. Will definitely pay attention to proximity.

I would try a series of smaller magnets adding them until you find the right balance.

Good luck. I like the idea. If it can't be done with magnets, it shouldn't be done at all!

That seems to be the wisdom I'm finding. The 405th has a few threads on it to attach the various Halo weapons.

How about an electromagnet powered by 9 volts where the magnets are activated by a microswitch? Unsure of how much time the weapon was to remain slung, the or battery life.

TazMan2000

I read one idea about using an electromagnet but where its non-powered state is magnetized, and then when you activate it, then it actually reverses polarity. So you could have a pressure switch on the gun that you activate when you grab it off your back, and at that point it repels the magnets. I need to research it a bit more but sounds like a fun idea.
 
Along with what others have said:

Use multiple magnets, in different orientations so that when you go to snap them back they self-align.

Magnets hold very well in one direction, but they do very little to prevent sliding. Adding some short pins or other small hook will prevent the prop from slipping down your back, but still allow for a quick release.

Do not allow the magnets to smack metal-on-metal. Rear-earth magnets are NOT solid metal objects like they look. They are nickel plated powder. If you break the nickel plating then the powder inside will come out and they will never work the same again. Adding a coating of rubber such as plastidip provides a small amount of cushion, and can even hold together a cracked magnet. They also help with the sliding friction. But be aware, if you put rubber on both sides, the rubber can fuse over time if you leave the magnets connected.

No matter how strong the magnets, they will not interfere with batteries, LED or other electronics. Unless your are planning on using 3.5" floppy disks, or a CRT monitor on your prop, you will be just fine.

Regarding releasing the magnets, look into electric door holders. They make models which use permanent magnets to hold, and electromagnets to release. However, most are just an electromagnet.
 
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