[Amps] current threads about silver solder and resoldering

[Roger (K8RI)]

On 9/1/2012 2:26 PM, Manfred Mornhinweg wrote:
> Bill,
>
>> Most things are labeled the largest component to the smallest by weight,
>
> Yes, for example the list of chemicals in food is like that. But solder
> normally isn't. I think there is an ISO standard defining solder alloys,
> and it requires tin contents to be specified first. I would have to
> search for it to provide any evidence, though.
>
>> Such as eutectic alloy of 63% tin, 37% lead.
>> Oddly enough with that ratio by weight the number of atoms of each is
>> equal.
>> One atom of lead to one of tin.
>
> I strongly disagree. Tin has much lower atomic weight than lead. If
> there is far more tin, by weight, than lead, then the ratio of atoms of
> tin to atoms of lead is even larger. According to my calculation, 63/37
> solder has slightly more than 3 atoms of tin for each atom of lead.
>

Lead = 207.2
Tin 118.7

Figuring gram molecular weights

63% of 118.7 = 74.781grams/molecules
37% of 207.2 = 76.664grams/molecules

They are close but not exact or they just round off to the nearest % for 
simplicity.

I would think to be eutectic they would be the same, but due to 
measuring tolerances this is pretty close.

73

Roger (K8RI)

> Manfred
>
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