Mercury substitute for old elec motor?

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wb2tdg Active Contributor Join Date: Jul 2007 Posts: 11	Mercury substitute for old elec motor? 10/29/2007 8:40 PM
	I mainly make model steam engines as a hobby but want to make a few old type motors that use mercury for the commutator. Since this will displayed at model shows I am looking for an inexpensive substitute for mercury. I don't care if if looks like mercury as long as its fairly safe to handle and will conduct well enough to run small 6-12 volt motors. An example of what I plan to make maybe seen at http://physics.kenyon.edu/EarlyApparatus/Electric_Motors/Rotation_of_Magnetic%20Pole/Rotation_of_Magnetic_Pole.html I have looked into liquid gallium but not sure if its available or how safe it is to use. I wondering if there is anything I could just add to plain water to make it conduct well enough for these simple motors Ken Brockway
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bob c Guru Join Date: Jul 2007 Location: Fort Lauderdale Florida Posts: 5708 Good Answers: 123	#1 Re: Mercury substitute for old elec motor? 10/30/2007 7:36 AM
	Two possibilities that comes to mind. 1) Fill the cavity with powdered aluminum and a light oil mixture. Perhaps powdered copper and oil. 2) If the cup that is supposed to hold the mercury is lined with a brass or copper ring on the bottom, you could let a braided copper brush drag across the bottom, and cover it with any liquid. __________________ Bob
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Electroman Guru Join Date: Jul 2006 Location: Dunstable, England Posts: 2821 Good Answers: 45	#2 Re: Mercury substitute for old elec motor? 10/30/2007 9:53 AM
	I would just use mercury, i've about a kilo of the stuff laying about in my workshop if you want some... John. __________________ A little knowledge is a dangerous thing - Googling is far worse!
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bob c Guru Join Date: Jul 2007 Location: Fort Lauderdale Florida Posts: 5708 Good Answers: 123	#3 In reply to #2 Re: Mercury substitute for old elec motor? 10/30/2007 10:13 PM
	Here in the U.S. they are so against mercury that Ford has stopped selling it's Mercury line of cars. __________________ Bob
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aurizon Guru Join Date: Jun 2006 Location: Toronto Posts: 3968 Good Answers: 120	#4 Re: Mercury substitute for old elec motor? 10/30/2007 11:19 PM
	http://www.google.ca/search?hl=en&q=gallium+alloys&btnG=Google+Search&meta= some are liquid at room temp __________________ Per Ardua Ad Astra
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BlueAussieBoy Power-User Join Date: Sep 2006 Posts: 451 Good Answers: 16	#5 Re: Mercury substitute for old elec motor? 10/31/2007 12:48 AM
	Why not use mercury and just put a bell jar (with an O ring seal) as a cover the top of the whole thing? This would be in keeping with the fashion of the era and prevent any mercury vapour being inhaled by the operator or the public. It would also protect from winds and dust and keep the whole thing looking nice and polished. __________________ Make it so.
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Electroman Guru Join Date: Jul 2006 Location: Dunstable, England Posts: 2821 Good Answers: 45	#6 In reply to #5 Re: Mercury substitute for old elec motor? 10/31/2007 8:22 AM
	Or better still just use mercury and put a light oil over the surface to trap any mercury vapour released... You will then be able to use it as originally designed. John. __________________ A little knowledge is a dangerous thing - Googling is far worse!
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Anonymous Poster	#7 Re: Mercury substitute for old elec motor? 10/31/2007 11:51 AM
	http://www.popsci.com/popsci/how20/b1c89aa138b84010vgnvcm1000004eecbccdrcrd.html
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sidevalveguru Power-User Join Date: Jan 2007 Location: The Capital City, Cow Hampshire, USA Posts: 476 Good Answers: 3	#8 Re: Mercury substitute for old elec motor? 10/31/2007 7:12 PM
	Perhaps a saturated salt/water solution ("brine") would offer the conductivity you require? Watch for corrosion afterward; wash after use. __________________ If you always do what you've always done, You'll always get what you've always had!
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Anonymous Poster (1); aurizon (1); BlueAussieBoy (1); bob c (2); Electroman (2); sidevalveguru (1)

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