[TheForge] Re: magnets as latches

[GHS]

Also, and perhaps more to the point, will the fire codes allow them?

Mike Graf

Roger Olsen wrote:
> Let me try asking the question this way________do any of you have actual
> experience using magnets for a closing system on firedoors?  I am not asking
> those of you who have guesses or assumptions or opinions, only those of you who
> have actually used them and what you found______did the doors latch the same
> two years from day one or did they loose a lot if not all of their magnetic
> qualities.
> 
> Thanks,
> R Olsen
> __________________________
> 
> Steve Smith wrote:
> 
> 
>>I don't have a clue, Roger. I did find a list of Curie point
>>temperatures for different materials. Here are a few (in degrees
>>Kelvin--subtract 273 and you have Centigrade):
>>Iron 1043
>>Cobalt 1388
>>Nickle 627
>>source: http://www.nationmaster.com/encyclopedia/ferromagnetism
>>
>>etc. So your question is good, how soon do you see effects? It also
>>looks like you have a huge effect in the actual temp by what alloy
>>you're magnet is made of. I don't think this helps, just more info.
>>
>>Steve Smith
>>
>>Roger Olsen wrote:
>>
>>
>>>So I assume the higher the heat the faster the magnetic loss but when does
>>>the affect kick in?  100 degrees________300 degrees_________500
>>>degrees________700 degress?
>>>
>>>Does anyone know the answer to this?
>>>
>>>R. Olsen
>>>_______________________
>>>
>>>Bruce Freeman wrote:
>>>
>>>
>>>
>>>>Clearly, when steel goes non-magnetic, if the steel WERE a magnet it
>>>>wouldn't be afterwards.
>>>>
>>>>However, any heating or hammering will reduce or destroy the magnetic
>>>>properties of a steel magnet.
>>>>
>>>>If using a magnet as part of a door latch:
>>>>
>>>>First, be aware that those rare earth magnets can be VERY strong.
>>>>Think pinch-points when using them in a design.
>>>>
>>>>Second, you may want to move the magnet itself away from the heat.
>>>>Imagine, for example, using a horseshoe magnet as the handle on a hot
>>>>door.  The cooler handle will be less likely to lose its magnetic
>>>>properties.  But if constructed correctly, this remote handle could be
>>>>an effective latch for the door, since the magnetic forces will follow
>>>>the path of the steel.  (Constructed incorrectly, there would be no
>>>>magnetism to latch the door, however.   Avoid a complete loop.  Think:
>>>>"horseshoe" shape.)
>>>>
>>>>Bruce
>>>>NJ
>>>>
>>>>
>>>>
>>>>>>>erik at methow.com 5/13/2004 12:22:50 PM >>>
>>>>
>>>>Hey Andy,
>>>>
>>>>Ask your friend one other thing about magnets.  I wonder about heat, at
>>>>what
>>>>point does it drain a magnet of its magic affects?   I have never used
>>>>them on
>>>>fire doors but I know many have.  I have considered using them in the
>>>>past and
>>>>I am sure I will again in the future.
>>>>
>>>>If I did I would use the 'Rare Earth Magnets' sold by Lee Valley and
>>>>others as
>>>>well.  They seem to be about 10 times stronger than the radio shack
>>>>type
>>>>magnets.
>>>>
>>>>Roger Olsen
>>>>__________________________________
>>>>
>>>>Gladish Family wrote:
>>>>
>>>>
>>>>
>>>>>>1. I have a number of assorted magnets used for set-ups, mock ups
>>>>
>>>>and
>>>>
>>>>
>>>>>>the like...should they be stored separately, carefully aligned
>>>>>>north/south, to retain max  pull ( suck?) or is it not a problem
>>>>
>>>>just to
>>>>
>>>>
>>>>>>toss them in a box with their friends?
>>>>>
>>>>>My understanding is that magnets are manufactured by applying
>>>>
>>>>overwhelming
>>>>
>>>>
>>>>>magnetic fields (i.e. really really huge!) to a previously neutral
>>>>
>>>>chunk of
>>>>
>>>>
>>>>>metal, and that heat or overwhelming magnetic force are the only ways
>>>>
>>>>that
>>>>
>>>>
>>>>>magnets lose their pull, other than physical deterioration.
>>>>>I have a friend who sells magnets for a living- I'll ask him.
>>>>>Andy G.
>>>>>
>>>>>_______________________________________________
>>>>>Manage membership or unsubscribe at:
>>>>>http://mailman.qth.net/mailman/listinfo/theforge
>>>>>theforge mail list group photo site is
>>>>>http://www.photoaccess.com
>>>>>Login:  blacksmithblacksmith at hotmail.com
>>>>>password:  anvil
>>>>>___________
>>>>
>>>>_______________________________________________
>>>>Manage membership or unsubscribe at:
>>>>http://mailman.qth.net/mailman/listinfo/theforge
>>>>theforge mail list group photo site is
>>>>http://www.photoaccess.com
>>>>Login:  blacksmithblacksmith at hotmail.com
>>>>password:  anvil
>>>>___________
>>>>
>>>>_______________________________________________
>>>>Manage membership or unsubscribe at:
>>>>http://mailman.qth.net/mailman/listinfo/theforge
>>>>theforge mail list group photo site is
>>>>http://www.photoaccess.com
>>>>Login:  blacksmithblacksmith at hotmail.com
>>>>password:  anvil
>>>>___________
>>>
>>>
>>>_______________________________________________
>>>Manage membership or unsubscribe at:
>>>http://mailman.qth.net/mailman/listinfo/theforge
>>>theforge mail list group photo site is
>>>http://www.photoaccess.com
>>>Login:  blacksmithblacksmith at hotmail.com
>>>password:  anvil
>>>___________
>>>
>>>
>>>
>>
>>_______________________________________________
>>Manage membership or unsubscribe at:
>>http://mailman.qth.net/mailman/listinfo/theforge
>>theforge mail list group photo site is
>>http://www.photoaccess.com
>>Login:  blacksmithblacksmith at hotmail.com
>>password:  anvil
>>___________
> 
> 
> _______________________________________________
> Manage membership or unsubscribe at:
> http://mailman.qth.net/mailman/listinfo/theforge
> theforge mail list group photo site is
> http://www.photoaccess.com
> Login:  blacksmithblacksmith at hotmail.com
> password:  anvil
> ___________
> 
> 
> 
> 
> _____________________________________________________
> This message scanned for viruses by CoreComm
> 
> 

-- 
  Please visit us at http://www.gaudeteforge.com/