Magnetic field paper - UK Vintage Radio Repair and Restoration Discussion Forum

ppppenguin · 23rd Mar 2011, 11:57 pm

This stuff looks rather nice: http://www.first4magnets.com/iron-po...paper-17-c.asp

It sounds a bit like the magnetic version of Teledeltos paper. This used to be used for plotting electric fields but is apparently no longer available.

mrmagnetophon · 24th Mar 2011, 2:01 am

yes i could use some too if anyone could find it.
-Chris

AVO_VCM163 · 24th Mar 2011, 8:28 am

Available both through eBay and Amazon. Search for "Field Paper"
Approx £10 for 50mm x50mm or £40 for 300 x 300 mm.
R

David G4EBT · 24th Mar 2011, 8:10 pm

You can achieve the same effect by placing a sheet of paper over glass, putting the magnet beneath the glass, then sprinkling iron filings onto the paper, whereupon the flings will reveal the lines of force of the magnet. To illustrate the point, I've attached some pics of two magnets - one of a 'U' shaped magnet - the other of a small neodymium magnet (just 6mm diam x 3mm thick), these being exceedingly powerful rare earth magnets.

The 'iron filings' are a bit coarse - they were just picked up with a magnet from the grindstone that I use to sharpen my woodturning tools. Finer filings would show the effect much better, but I hope the pics give a bit of an idea.

I should add that neodymium magnets must be handled with great caution.

A 20mm diam neodymium magnet typically has a 12lb (5.5kg) pull, and magnets larger than a few centimeters are strong enough to cause injuries to body parts pinched between two magnets, or between a magnet and a metal surface, even causing broken bones. Magnets allowed to get too near each other can strike each other with enough force to chip and shatter the brittle material, and the flying chips can cause injuries. There have even been cases where young children who have swallowed several magnets have had a fold of the digestive tract pinched between the magnets, causing injury or death. (They can also cause pacemakers to malfunction).

Another hazard - though not a danger to health (apart from losing ones's sanity!) is the risks to hard drives, credit card chips etc, if in close proximity to these magnets, causing data to be damaged or destroyed.

Hope that's of interest.

David

23rd Mar 2011, 11:57 pm	#1
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Magnetic field paper This stuff looks rather nice: http://www.first4magnets.com/iron-po...paper-17-c.asp It sounds a bit like the magnetic version of Teledeltos paper. This used to be used for plotting electric fields but is apparently no longer available.

24th Mar 2011, 2:01 am	#2
mrmagnetophon Retired Dormant Member Join Date: Sep 2010 Location: Ohio, USA. Posts: 757	Re: Magnetic field paper yes i could use some too if anyone could find it. -Chris

24th Mar 2011, 8:28 am	#3
AVO_VCM163 Retired Dormant Member Join Date: Mar 2008 Location: Hampshire, UK. Posts: 297	Re: Magnetic field paper Available both through eBay and Amazon. Search for "Field Paper" Approx £10 for 50mm x50mm or £40 for 300 x 300 mm. R

24th Mar 2011, 8:10 pm	#4
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,768	Re: Magnetic field paper You can achieve the same effect by placing a sheet of paper over glass, putting the magnet beneath the glass, then sprinkling iron filings onto the paper, whereupon the flings will reveal the lines of force of the magnet. To illustrate the point, I've attached some pics of two magnets - one of a 'U' shaped magnet - the other of a small neodymium magnet (just 6mm diam x 3mm thick), these being exceedingly powerful rare earth magnets. The 'iron filings' are a bit coarse - they were just picked up with a magnet from the grindstone that I use to sharpen my woodturning tools. Finer filings would show the effect much better, but I hope the pics give a bit of an idea. I should add that neodymium magnets must be handled with great caution. A 20mm diam neodymium magnet typically has a 12lb (5.5kg) pull, and magnets larger than a few centimeters are strong enough to cause injuries to body parts pinched between two magnets, or between a magnet and a metal surface, even causing broken bones. Magnets allowed to get too near each other can strike each other with enough force to chip and shatter the brittle material, and the flying chips can cause injuries. There have even been cases where young children who have swallowed several magnets have had a fold of the digestive tract pinched between the magnets, causing injury or death. (They can also cause pacemakers to malfunction). Another hazard - though not a danger to health (apart from losing ones's sanity!) is the risks to hard drives, credit card chips etc, if in close proximity to these magnets, causing data to be damaged or destroyed. Hope that's of interest. David Attached Thumbnails