Magnets as Connectors

[beamis]

So I was in Harbor Freight and saw some neodymium magnets cheap and figured I'd try to solder some leads to them and use them to charge D-cells in my C9000. The heat of the soldering iron destroyed the magentism. I've heard of people using magnets, but how?

 

[Mark620]

solder a piece of steel to the lead and then the magnet will hold to the wire and battery.

Unless you have the right type of welder.

 

[T0RN4D0]

If you are fast enough and dont overheat the magnet you won't destroy it. also stick the magnet to a piece of iron so it will heat up less, prepare your wire, keep everything clean and just pop it on the magnet, you should be done in less than a second :]

I did this to a neo magnet the other day; soldered a resistor to it just for test, first day the resistor line broke when i tested if it holds... But the next day the joint just fell off. The magnet wasn't properly cleand tho, but really it surprised me how well it held the first day and then just bam and its off.

I'm waiting for 100 magnets now so i can make some holders.

 

[65535]

Keep in mind a lot of magnets are nickel plated (I believe) at any rate the plating is pretty weak, and solder doesn't stick to the core of the magnet, but it does stick to nickel.

So don't be surprised if the weak plating tears off.

 

[Apollo Cree]

Aren't there fire and toxicity concerns with neodymium?

 

[65535]

Aren't there fire and toxicity concerns with neodymium?

Pure Neodymium yes, but the magnets are only a Nd containing compound. They do not have the burning issues that pure Nd does.

 

[qwertyydude]

You need a very hot iron and a drop of flux doesn't hurt either, I use a dual power on 30 watts with a 120 watt turbo mode. I use the turbo to heat a blob of solder on the iron really hot and put a drop of flux on the magnet and all you have to do is touch hot solder to the magnet with flux and it instantly tins the magnet in less than half a second, too quick to transfer enough heat to demagnetize it. Then let it cool completely and just simply stick the wire and solder it quickly and you'll get it done.

 

[SnowplowTortoise]

Samarium Cobalt (SmCo) magnets can withstand high temperatures much better than Neodymium, but they are more expensive and more brittle. If you find that you are demagnetizing the Nd magnets, maybe give them a try.

Personally, I'm no soldering pro, but I've had good results soldering to Nd magnets. I sand off the shiny coating, stick them to an anvil (actually, it's a scrap of a train track), and use a 300 watt soldering gun to get the job done quickly. The hardest part is pulling the tip of the soldering gun away from the magnet. Those suckers are strong!

Also, I think the size of magnet is an important factor here. It seems to me, the bigger the magnet, the less likely you are to demagnetize it by heating up one surface. The magnets I have used are 0.375" DIA x 0.25" THK, which makes them much stronger than necessary for the job of holding a wire to a battery (in fact, it can be a little annoying to try to pry them apart). Good luck!

 

[T0RN4D0]

The bigger the magnet, more time you need to overheat it. Small ones get hot in seconds... I will try to solder to 8mm dia 1mm thin magnets for my holders... then i'm just gonna put two or three together probably and shrink wrap them.

 

[1 what]

My experience has been in line with 65535's.
A lot of the time the plating tears off with a bit of use.
I sometimes use thin Cu tape with a lead soldered to the tape and the tape between the magnet and the Fe metal but most of the time (these days) I try to avoid using magnets in this way.

 

[BoarHunter]

Just use standard soldering eylets for M3 screws for ex. http://www2.schukat.com/schukat/sch...11&refDoc=CMS3CFF44758E296298C125708500343CFA

Solder the wire to it.
Smear your small magnet (8 to 10 in diam) with cyano glue and glue it to the eyelet. If necessary scrap the glue that passed to the other side which will be the contact.
Despite the eyelet thickness, the holding force will be plenty enough.

 

[ubetit]

A hot iron, steady hand, flux and lead-free silver bead solder (non-rosin core) works very well.

 

[cy]

yup magnet tipped leads will work for charging ... but why bother when one can construct a proven/cheap charging clamp for under $10.

charge clamps are MUCH more versatile... multiple batteries clamped under light compression have no contact/resistance issues.

for instructions follow link in my sig.. note date of posting... this is a proven and inexpensive design.

I get requests to build this charging clamp for sale regularly... flat don't have time. sure wish someone would build a few of these for re-sale.

 

[eebowler]

I use 1/2 inch cylinder magnets. The charger connectors are alligator clips which stick readily to the magnets. No soldering... I've charged at 5A without any problems.

If you can get hold of small ring magnets, I've soldered the wire lead to the pointy end of a metal thumb tack and put a ring magnet over the wire and onto the tack. Its attraction keeps the tack firmly attached to the battery.