Any reason a buyer identifying brass would use a Gold silver Acid test to confirm

Hi I've been scrapping a couple times a month now for a couple of years. Recently I took some brass and copper items for scrap. Among the items were internal parts coming from the internals of either defense electronics or electronic testing and calibration units that had once been gone trough for the tubes and transistors. While taking much of this stuff apart I could not help but be amazed by the high degree of precision construction. If there were moving gears or rods they were usually made of machined brass and maybe use some stainless steel bearings.

One piece which was a Silver in color from surface and trough out its construction. It was rectangular housing for other moving rods and gears which measured approximately 6" long x 4" Width x 1 1/4" depth and having approximately a 1/4" thick walls. I simply wasn't sure what it was made of but the machining was immaculate and the weight of it was impressive. Over 3 lbs.

I held the item separate and it was the last thing I gave the buyer telling him, I am not sure what this is. So he takes the item over to the grinding wheel and grinds it. Just as I have seen and witnessed many buyers do to identify brass items. But in this case after he put it on the grinding wheel he kind of got a funny look on him and then walked over to his desk and performed a liquid acid test on it. Then he turned and said, Wow you got one heavy piece of brass here. I asked is that what it is because I was not sure, he stated yep its one heavy piece of brass. I got approximately $4.10 for it.

But I couldn't help notice the feeling in my gut, that the whole exchange just seemed odd. I have never seen a buyer go beyond using a grinder and need to take a potential piece of brass and perform an acid test on it to say it was brass.

Is there a brass used that is silver through and through? Would a acid test determine if something was brass? Would there be a reason that a experienced scrap metal buyer would need or want to use a acid test after a grinding wheel to identify something as being brass? Or if you were to grind silver or even platinum would it be fairly obvious and therefore create a need to perform an acid test on it to confirm an expert buyers suspicions. Is it possible that I gave away over 3 lbs of silver that would have been worth over $700? or even worse if by chance it would have been platinum?

I realize its to little to late and that I made a critical mistake in not having it tested or witnessing the testing of the piece. I am just curious to have some experienced scrappers give me their answers to my questions. Thanks!

Brass bubbles green with an acid test.

Many times, specially with sensitive military electronics, metal inside electronic devices is plated with some type of precious metals for the purpose of RF Shielding. If he realized that these were the internal metal structures inside an electrical device, specially if it was military in nature, he may have been using the acid test to see if they were plated or contained precious metals.

Metals commonly used for shielding are silver, gold, sometimes platinum but not very common.

The shielding is of the thickest type. This causes gold plated shielding to look dull, almost like butter, on the metal. Where thin gold plating is very shiny. Here is an example of a piece of Al that came out of military electronic equipment that had gold plated shielding:

https://www.dropbox.com/s/b5wx6mzzxy...26.39.jpg?dl=0

I would suggest learning and keeping an acid test kit handy if you come into contact with any material where the metal could possibly be plated in this way. It would be to your benefit as this type of thing is fairly common in certain electronics.

Scott

Should have went with your gut feeling.
Live and learn. Good luck. Thanks for the info, learn something new everyday here!

When taking apart electronic equipment, especially defense, computer, testing, aviation, medical and/or unique types of devices. Things to note and maybe research before you even start a tare down and scraping of such equipment. Is the manufacturers name, part number, serial number, revision notes and date of manufacturer, these will usually be on a "data plate". This data plate will be sometimes attached to back of a device, inside of case, and repeated in some way on each major component of the device. This type of equipment has regular maintenance and calibration cycles that require these data plates.

For you the data plate is where you start your research on what you have! With this you should be able to find user manuals, maintenance and possibly a IPC (ILLUSTRATED PARTS CATALOG). This is all part of what is called TECHNICAL DOCUMENTATION PROCEDURES and part of that procedure starts with a data plate on individual pieces of equipment. This is not just for "high end", unique instrument but just about all electrical and electronic equipment has a identifying method or standard. As the manufacturers, trade groups, organizations and governments require them. The data plate could be a actual metal plate or could be a sticker. glued on paper, and even engraved/etched onto the equipment.

Trust me it can be beneficial financially to take a little time before you tear it apart and into "buckets". The device could have been more valuable as is. Much more valuable than a piece of scrap metal, even silver or gold!

Quote:

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Originally Posted by supwitron

hey shred jumped up to 55 dollars a ton, nows your chance to take in a bunch of catalytic converters and still get a couple cents.

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troll

Here are some gold plated RF connectors and the circuit board they plug into, this board was made in 1978.http://i782.photobucket.com/albums/y...ps0c1900aa.jpg

I would not beat your self up of it .
The two most esteemed Japanese alloys are shakudo and shibuichi. Copper & silver but it's use seems as decorative
Copper and zinc are primarily brass I have had brass items that seemed very faint in color (more silver in color ) after grinding but hey it's brass .
I can't see any reason silver would be used pure . Nickel and Nickel alloys are used due to strength & pure nickel is ferris
True quality Stainless steel is non ferris and heavy , The yard guy might of wondered if it was a chunk of Stainless steel
Germain silver alloy is copper alloy with nickel and zinc. are consider decorative brass at the yards .

But PM use in electronics and RF shielding is what it's all about for the scrapper who organize those item types to sell at utmost true value
any brass alloy sold to yard is brass & I highly doubt the yard put it aside to sell as any thing more then brass.