Hi All,
The easiest way to think of this is not the use of a complicated formula,
but the simple application of percentage.

In the example below, the total weight of tin plus lead is 1500 pounds,
61.9% of which is tin. Hence there are 928.5 pounds of tin.
Add 45 pounds of tin, the total weight is now 1545 pounds of which, 973.5
pounds is tin. Work out the new percentage of the new total weight and you
get 63%.
Ahah, I hear you ask, how do you get to 45 pounds in the first place? Well,
just plug a few numbers into the percentage calculations and see which
direction it takes you.
The main thing to remember is that you add the tin addition to the total
weight as well as the tin content when working out the new percentage.
Hope this helps
Regards
Eric Dawson

> -----Original Message-----
> From: Stephen R. Gregory [SMTP:[log in to unmask]]
> Sent: Wednesday, October 24, 2001 4:19 PM
> To:   [log in to unmask]
> Subject:      Re: [TN] Adjusting the alloy composition in the solderpot
>
> Hi Daan!
>
> I had that happen to me back in May of this year. Our analysis came back
> and we were at 61.9%. On my analysis sheet, it was recommended to add
> 3-lbs of pure tin for every 100-lbs of solder to bring the pot back back
> to a nominal 63%...
>
> I'm no metallurgist, nor am I a good mathematician (I think everybody on
> the TechNet knows that...hehehe). But we have a 1500-lb pot, and I put
> 45-lbs. of pure tin in as recommended, the next sample after that we were
> dead-on 63%...
>
> Maybe somebody better at math than me can decipher a formula from that...
>
> -Steve Gregory-

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