Demagnetizer

[Don42]

Small hand tools like screwdrives and tweezers sometimes get magnetized. That can sometimes be useful, but other times a nuisance. I made a demagnetizer out of a soldering gun -- and the soldering gun can also be quickly restored to its original purpose.

I made a three-turn coil out of 6 gage solid copper ground wire, which is sold by the foot at Home Depot. I wound the wire around a 3/4" dia piece of cold roll to use as a mandrel. I made two nuts (7/16 x 14tpi) out of brass, with holes thru them. The holes are bigger than the original nuts; I made them 0.228" (#1 drill) to comfortably clear the .204" dia copper wire. I also made little washers to silver-braze on the ends of the coil so the nuts could hold the coil in the soldering gun.





That's all there is to it! Insert the tool (screwdriver, whatever) into the coil, pull the trigger on the soldering gun and slowly withdraw the tool. You'll notice that the coil's magnetic field exerts a fairly strong attraction to a ferromagnetic object within it. When the tool is well clear of the coil, release the trigger. Best not to hold it down too long because the coil will get quite hot fairly quickly. It can also re-magnitize tools. Insert tool into coil, pull trigger and release. Test for magnetism. The trigger must be released when the 60 Hz line voltage is near its peak. That's trial and error but it never takes more than a few tries.

I did some measurements. The current flowing thru that coil is 990 amps!

[DIYer]

Thanks Don42! We've added your Demagnetizer to our Electrical category,
as well as to your builder page: Don42's Homemade Tools. Your receipt:

Demagnetizer by Don42

tags: demagnetizer

[paulk]

Slick!! I need to magnetize a dipstick. This should work great. Paulk

[ranald]

Small hand tools like screwdrives and tweezers sometimes get magnetized. That can sometimes be useful, but other times a nuisance. I made a demagnetizer out of a soldering gun -- and the soldering gun can also be quickly restored to its original purpose.

I made a three-turn coil out of 6 gage solid copper ground wire, which is sold by the foot at Home Depot. I wound the wire around a 3/4" dia piece of cold roll to use as a mandrel. I made two nuts (7/16 x 14tpi) out of brass, with holes thru them. The holes are bigger than the original nuts; I made them 0.228" (#1 drill) to comfortably clear the .204" dia copper wire. I also made little washers to silver-braze on the ends of the coil so the nuts could hold the coil in the soldering gun.





That's all there is to it! Insert the tool (screwdriver, whatever) into the coil, pull the trigger on the soldering gun and slowly withdraw the tool. You'll notice that the coil's magnetic field exerts a fairly strong attraction to a ferromagnetic object within it. When the tool is well clear of the coil, release the trigger. Best not to hold it down too long because the coil will get quite hot fairly quickly. It can also re-magnitize tools. Insert tool into coil, pull trigger and release. Test for magnetism. The trigger must be released when the 60 Hz line voltage is near its peak. That's trial and error but it never takes more than a few tries.

I did some measurements. The current flowing thru that coil is 990 amps!

Very Interesting!

[11thhourfabrication]

Small hand tools like screwdrives and tweezers sometimes get magnetized. That can sometimes be useful, but other times a nuisance. I made a demagnetizer out of a soldering gun -- and the soldering gun can also be quickly restored to its original purpose.

I made a three-turn coil out of 6 gage solid copper ground wire, which is sold by the foot at Home Depot. I wound the wire around a 3/4" dia piece of cold roll to use as a mandrel. I made two nuts (7/16 x 14tpi) out of brass, with holes thru them. The holes are bigger than the original nuts; I made them 0.228" (#1 drill) to comfortably clear the .204" dia copper wire. I also made little washers to silver-braze on the ends of the coil so the nuts could hold the coil in the soldering gun.





That's all there is to it! Insert the tool (screwdriver, whatever) into the coil, pull the trigger on the soldering gun and slowly withdraw the tool. You'll notice that the coil's magnetic field exerts a fairly strong attraction to a ferromagnetic object within it. When the tool is well clear of the coil, release the trigger. Best not to hold it down too long because the coil will get quite hot fairly quickly. It can also re-magnitize tools. Insert tool into coil, pull trigger and release. Test for magnetism. The trigger must be released when the 60 Hz line voltage is near its peak. That's trial and error but it never takes more than a few tries.

I did some measurements. The current flowing thru that coil is 990 amps!

just for your information. You can get brake line tubing nuts that have a 7/16-14 thread.

[thevillageinn]

Thanks for the inspiration! I made a similar coil for my soldering gun which has taken care of the fine steel swarf from filing and grinding from hanging on my screwdrivers. I didn't have any copper as heavy as yours but I had some 12ga which I twisted together and bent to fit.

[Don42]

Thanks for the inspiration! I made a similar coil for my soldering gun which has taken care of the fine steel swarf from filing and grinding from hanging on my screwdrivers. I didn't have any copper as heavy as yours but I had some 12ga which I twisted together and bent to fit.

Glad it's working for you. Swarf on tools can be a real nuisance!

[mr_modify1]

Nice job great idea.