# Formula To Calculate How Much Gold is in A Circuit Board



## peethom (Apr 18, 2013)

I am a newbie at this but I managed to get my hands on some computers and old cell phones so now i am presently doing some research to determine how much gold is in them. I'm hoping to get some advice for anyone to check out this scientific method used 

In order to calculate the amount of gold I was advised if i use the formula from http://www.finishing.com/269/90.shtmlm I should come up with a good estimate...

A typical PCI circuit board used today in a personal computer has gold edge connectors 
that are plated fifty millionths of an inch (0.000050")thick with gold. 

IN ORDER TO PUT MY NEWLY FOUND CALCULATION TO THE TEST I USE THE A CELL PHONE WHICH 
CAN BE SEEN AT http://farm9.staticflickr.com/8242/8660550413_72e3f1ebca_z.jpg

As you can see from the photo, this phone's circuit board comes in two sections ...The first section contains
six blocks of gold estimated to be 2.4sq in. And the keyboard gold connectors is estimated at 2.4sq in as well.

So, multiply the following conversions to get:

SECTION A = 2.4 sq in * .00005 in X 16.39 cu cm per cu in X 19.3 g per cu cm X .03222 troy oz per gram 
X $1,659.00 per tr oz = $1.71 for this particular section of gold on the phone.

SECTION B = The area of gold in the keyboard section is also estimated at a ballpark
figure of 2.4sq in (Give or Take)

Therefore SECTION A + SECTION B equals $3.42 worth of platted gold (not including the pins and other gold components.

The conversions used from the calculations are:

The density of gold is 19.3 grams per cubic centimeter 

There are 16.39 cubic centimeters in a cubic inch.

$1,659.00 per troy ounce is a crude estimate of the current price of gold.

.03222 troy ounces per gram is the inverse (upside down) 1 tr oz per 31.035 grams.


Can anyone out there tell me if this is a good ballpark figure. I am sure there are many variables that can throw this off like the thickness of the gold plate.


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## jimdoc (Apr 18, 2013)

peethom said:


> I am a newbie at this but I managed to get my hands on some computers and old cell phones so now i am presently doing some research to determine how much gold is in them. I'm hoping to get some advice for anyone to check out this scientific method used
> 
> In order to calculate the amount of gold I was advised if i use the formula from http://www.finishing.com/269/90.shtmlm I should come up with a good estimate...
> 
> ...



Calculating what amount of gold you should be able to recover, and what you are actually able to recover can vary greatly. I think the amount of gold you can actually recover from any item is more important than a guess of what you should.

Unless you have many boards of the same exact type, I feel you are wasting your time.

Jim


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## srlaulis (Apr 18, 2013)

I agree with Jim. Remove that which is easiest to refine and sell what's left, i.e. stripped motherboards, medium and low grade boards.


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## peethom (Apr 20, 2013)

OK, advice well taken. Thanks!


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## Marcel (Apr 20, 2013)

Cherry picking , that is what the large refiners hate about the hobbyists :lol:


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## peethom (Apr 22, 2013)

I think you may be missing to point a bit. Yes ...I am a beginner...And as a beginner, I need a few facts including approximately how many units do I need to hoard to meet my goal...or gold (Sorry...I couldn't resist that one :lol: )...But anyway...My main question, as well as many other fellow beginners is, How many computer boards or cell phones do i need to find before I can meet my profit target....I have spent weeks googling to find out that question and i still have not found a direct answer. I understand very well that the amount of goal in different CB's vary but I am not looking for exactness but a ball park, but people seem to avoid answering that question...Therefore my only hope was to at least calculate 10 or 20 different boards and come up with an average.


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## jimdoc (Apr 22, 2013)

peethom said:


> I think you may be missing to point a bit. Yes ...I am a beginner...And as a beginner, I need a few facts including approximately how many units do I need to hoard to meet my goal...or gold (Sorry...I couldn't resist that one :lol: )...But anyway...My main question, as well as many other fellow beginners is, How many computer boards or cell phones do i need to find before I can meet my profit target....I have spent weeks googling to find out that question and i still have not found a direct answer. I understand very well that the amount of goal in different CB's vary but I am not looking for exactness but a ball park, but people seem to avoid answering that question...Therefore my only hope was to at least calculate 10 or 20 different boards and come up with an average.



Look at what board buyers pay like;
http://boardsort.com/payout.php
http://thriftybits.com/

Try not to pay more than them. That would be a start.

Jim


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## resabed01 (Apr 22, 2013)

The reason you're not finding an answer is because there is no direct answer. The variables are too wide for circuit boards. Until you've refined the type of scrap you described and know your yields they would be only "guesses". Only then would you also know the costs involved with refining the above mentioned scrap.

I don't know what your profit target or goal is but I'm not sure you can approach E-scrap with the attitude that if you process X amount of circuit boards you will get $XX.XX back in profits.

Large refineries of E-scrap probably know the answers because they are experienced and properly setup to handle the volumes required to turn a profit.

If you want to narrow your focus onto certian types of E-scrap (CPUs, RAM, fingers, Black IC chips, etc) you'll find the yield numbers are more readly available. From that you'll find calculating your projected profits easier.


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## masonwebb (Apr 28, 2013)

jimdoc said:


> peethom said:
> 
> 
> > I think you may be missing to point a bit. Yes ...I am a beginner...And as a beginner, I need a few facts including approximately how many units do I need to hoard to meet my goal...or gold (Sorry...I couldn't resist that one :lol: )...But anyway...My main question, as well as many other fellow beginners is, How many computer boards or cell phones do i need to find before I can meet my profit target....I have spent weeks googling to find out that question and i still have not found a direct answer. I understand very well that the amount of goal in different CB's vary but I am not looking for exactness but a ball park, but people seem to avoid answering that question...Therefore my only hope was to at least calculate 10 or 20 different boards and come up with an average.
> ...



Wish I had that link when I started!


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## peethom (May 11, 2013)

Thanks for the valuable advice!


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