[TheForge] Re: Induction Forge?

[James Binnion]

The field strength falls off by the square of the distance, so unless  
you managed to get your torso into the coil or held the coil right  
next to the chest you would no get any significant energy into bone  
pins or leads of pacemakers. This is nothing like a MRI unit in field  
strength.

This rapid decrease in field strength is one of the main drawbacks of  
the induction heating of stock. The heating efficiency falls off  
dramatically with distance so that you need to make your coils come  
as close as possible to the item you want to heat with out touching  
it (you don't want to short out the coil) if you want to couple much  
power into the work.

I saw this unit at Seattle and it is definitely on my wish list. At  
$3800 it is about 10 times less expensive than the ones I have seen  
before.

Jim

On Aug 19, 2006, at 3:49 AM, Steve Smith wrote:

> Good point Mike.
>
> Steve
> who will get this project far enough to see some results in about  
> eight years
>
> Mike Spencer wrote:
>
>> sos> Apart from exploding tooth fillings there are a couple of less
>> sos> obvious hazards.
>> How about steel pins in the bones and epicardial pacemaker leads? [1]
>> I had a chance to take part in pour of several pounds of aluminum at
>> MIT, a demo for visiting high school students from Roxbury.  They  
>> were
>> to use an induction outfit that would do the melt in, IIRC, a few
>> seconds.  I opted to leave the building because no one had a clue
>> about the effect of large high frequency magnetic fields on the
>> pacemaker lead. [2]
>> - Mike
>> [1] Not to mention that the tiny, metal corkscrew tips of epicardial
>>     leads typically break off after a few years and migrate within  
>> the
>>     body, usually doing no harm.  But having it yanked hither and yon
>>     or heated to red would be a whole 'nother story.
>> [2] No pacemaker, just the lead, for reasons too off topic to get  
>> into
>>     here.
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James Binnion
jbin at well.com