How many computers for one ounce of gold?

A. Hi Clarence. Your inquiry is here, and we don't censor -- so anyone who wants to encourage you is welcome to. But gold recovery involves an awful lot more than muriatic acid; it's a complicated, multi-step, process.

And unless you have instrumentation and knowledge of how much gold you have, how will you even track at which step in the long process you might have washed any gold you had down the drain?

Anyone can suggest whatever they wish, but my suggestion is guitar playing, landscaping, or culinary arts rather than wasting time & money on gold recovery from electronics :-)

Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. I honestly do not know how many computer circuit boards you will need to strip to get one ounce of gold, but then again, I don't know how many fairies fit onto a pinhead. What I do know is that there is very little gold used on circuit boards and it is very difficult to recover. It will take you a lot of effort and leave you with a huge pile of worthless circuit boards that you will have to dispose of. Of course, you can scrape the gold off, but this will introduce other metals that will significantly devalue the gold. Once you have got your "gold" you will need to have it assayed before you can sell it. I would suggest you may be better off spending the time on studying your schoolwork and get prepared for an easier way of making your fortune.

I can, however, tell you about troy ounces and such. All precious metals and gems are handled in troy ounces and one troy ounce is 31.035g, compared with a "normal" ounce of 28.47g.

The troy system originated in the French town of Troyes, where they used a weights system based on 12 ounces to the pound, or 5,760 grains, or 0.3732kg.

A. 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. The finger area (measured and added up for both sides) equals almost exactly one square inch. So, multiply the following conversions to get:

1 sq. inch * .00005 inch * 16.39 cubic cm per cubic inch * 19.3 g per cubic cm * .03222 troy oz per gram * $400 per troy oz = $.20 per board

At this rate it will take a lot of circuit boards to get wealthy.

The conversions I used are:

The density of gold is 19.3 grams per cubic centimeter from the CRC Handbook of Chemistry & Physics [adv: on Amazon & AbeBooks & eBay affil links] .

There are 16.39 cubic centimeters in a cubic inch.

$400 per troy ounce is a crude estimate of the current price of gold.

.03222 troy ounces per gram is the inverse (upside down) fraction of the value our friend gave in the previous response, 1 troy oz. per 31.035 grams.

A. Here's another way to estimate gold plated value. You can do it in your head.

Divide the gold market price by 1000. At $400 gold: $400 divided by 1000 = $.40

This, 40 cents, is the approximate value of one square inch of gold plating, 100 microinches thick, at today's market price. This figure is used to calculate the value of items of known thickness.

About the thickest plating used today is on the all gold IC and CPU packages, which is about 40 to 60 microinches - let's say an average of 50, which is half of 100 or .5. On these parts, therefore, the value of the plating is about $.40 times .5 = $.20, or 20 cents per square inch.

Please forgive me, John, but, in my experience as a plater and a refiner, the average gold plating on fingers runs about 15 microinches thick, or a little less. This would make it worth about$.40 times .15 = 6 cents per square inch.

Thanks Chris. I was also thinking that John's thickness estimate seemed high, and when he noted that he was a retired plater I thought he might be retired for a few years now. I remember when the thickness was perhaps 100 microinches.

I serviced early generation electronic controllers for plating machines in the early seventies, and the lack of reliability of tin plated edge connectors made it relatively "cheap" to save service calls by gold plating them.

The idea of scraping the gold off sounds appealing at first, but when you run the numbers and need to scrape somewhere between 10,000 (for very old) and 100,000 (for new) fingers to get a 1-inch thickness, it gets less appealing.

A. Hi Kirk. Some of the info you seek is on threads 18889 "Removing gold from scrap electronics" and 29505 "Computer Metals Recycling". Good luck.

A. Three-fifths of a pound per ton of smartphones. Ten thousand phones weigh one ton.

A. Extracting gold from old desk top computers averaged .5 to 1.03 grams of gold. Gold has Bennett going up and down but at 1200 per ounce and 32 grams per ounce (31 something, I'm using simple math), it's about 37.00 bucks of gold; newer computers are about a 1/3 of a gram that's the RAM, board fingers, processors. And hard drives, this came out to about 10-12 bucks per computer.
SO: 10- 40 BUCKS OF GOLD PER COMPUTER

Hi. I'm sure it varies quite a bit, but the estimate I've heard, which sounds closer to believable to me, is one gram per pound.

Gold fever makes people who have not yet actually enjoyed any success ridiculously optimistic, talking as if they're already making big money, while at the same time it keeps those who have enjoyed even a smidgeon of success very untalkative. It's hard to get good numbers :-)

Luck & Regards,