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TIP: Choose your Magnets and Clamps


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Clamps are pretty straight forward:  Plastic with the rotating clamp head doesn't pinch as hard as metal and spreads out the force.  So it's going to do less damage to the plastic (may still want to put some electrical tape over them though).

 

Magnets are a little more complicated.  Rare Earth Magnets (Neodymium) strength varies based on two things:  size and rating.  The higher the rating (N32 to N52), the more pull strength.  The larger the size, the more pull strength.  Great, so what does that tell you?  Nothing.  Higher rating magnets cost more money, so larger magnets (that still work for your project) are more cost efficient than buying higher rating magnets.  Placing two equal size magnets to one another produces approximately the same pull force as one magnet of equivalent size also.

 

Here is a calculator that can help you compare magnet strengths:  http://www.kjmagnetics.com/calculator.asp

 

You can also browse various magnet pull strengths here:  http://www.kjmagnetics.com/magnetsummary.asp#discs

 

Back to the calculator:  Make sure to enter in the distance between the magnets, because it makes a BIG difference!  I used 4mm distance as a baseline.  FYI, N52 5/16" by 1/18" measures about 0.46 lb thru 4mm.  N52 3/4" by 1/18" measures 2.5lb thru 4mm.

 

I'd aim for 15-17mm and 20-25mm wide magnets to fit the arm and leg coverstrips.  Then compare prices of various thicknesses & ratings, while obtaining the amount of force you want them to have.  Try searching ebay in millimeters, not inches, for the best prices.  Higher quantity is usually the best deal too.  I actually found that I could get 100 20x3mm magnets for 10% cheaper than 50 20x5mm magnets.  So you have the option of double-stacking magnets for double pull strength, which is actually stronger than a single 5mm anyway, at a lower cost.

 

Hope this helps someone because the cost of magnets add up fast!

Edited by Kilryth
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Greatly appreciate this Kevin.

 

I've actually been doing some light (initial) research into the magnets lately as they are my 2nd planned purchase(s) moving forward (first is my DoopyDoos kit next month).  I had already decided that I would need more than one would like to initially think, because I'd like to be able to do BOTH shins/thighs/forearms, etc. on any given day as opposed to one on Monday, the other on Tuesday and the more magnets you have, the faster you can build.

 

Thanks again!

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No problem!!  I'll try to help you out a bit further by explaining what I decided to buy, so that I could have more magnets for less money.. thus less waiting, like you said.

 

The best value for me was:

 

----------

 

and

 

-------------

 

50 of each size magnet, which is plenty... costing between $0.44 and $0.60 each.

 

I think you'll find this to be an outstanding price for the size & pull strength, if you took the time to compare to more expensive N52 magnets in a practical use (such as 4mm distance between magnets).  The 20mm magnets have 50% more pull strength, when stacked together, for half the cost of the N52 3/4" ones.  The 15mm magnets have 4x the pull strength, without stacking, for approximately the same cost as the N52 5/16" ones, which are half the size & only cover half the width of the cover strip.

 

It was just a little more to get 50 versus 30, so may as well have extra if you need them.  I figured the most I would need at a time would be 36 for the legs and 24 for the arms, because I can't see myself gluing more than 4 pieces of armor at a time.

 

If I spaced each magnet out 1.5x its width along the coverstrips, which is the smallest amount of space I've seen them spaced, then I would need 18 per thigh coverstrip and 18 per shin coverstrip.  I would also need 12 per forearm coverstrip and 8 per bicep coverstrip.  Keep in mind, this many is not necessarily needed... but it's about as close as you can get them together practically.

 

Keep in mind, that you can also stack magnets, small and big ones, for more pull strength.  I plan on stacking my 15mm magnets on top of the 20mm magnets when I'm not using them.

 

If I end up with WAY too many magnets, I'll post them up for sale.  I'm sure I can find a use for them somewhere though. :)

Edited by gmrhodes13
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If I end up with WAY too many magnets, I'll post them up for sale.  I'm sure I can find a use for them somewhere though. :)

 

Is there such a thing? ;)

 

Great info btw. Thanks for sharing. 

 

-Eric

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  • 6 months later...

Been a while since I've been to this post, but with my armor delivery finally around the corner, I've actually purchased some magnets, and did so based on what I learned here in Kevin's post. So, to pay it forward, I'm sharing the ones that I found on Amazon tonight.

 

Here's the link: -------------

 

Thanks again, Kevin!!

Edited by gmrhodes13
link not working, removed gmrhodes13 2020
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