# E Scrap - Thanks for the help



## poet (Jan 29, 2011)

Thanks for the help.


*REMOVING/EDITING POSTS IN A MANNER THAT MINIMIZES OR DESTROYS A THREAD'S USEFULNESS TO THE FORUM IS UNACCEPTABLE. Doing so destroys the context and flow of the thread and sullies its value, in addition to hampering appropriate moderation. This type of behavior is to be avoided. ~~~Lou *


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## FrugalEE (Jan 29, 2011)

This is some kind of complex microwave/UHF transmitter, maybe for cell phone. The "Whatisit" is a UHF RF transistor. The white insulation may be Berillium oxide so be careful. There must have been a heat sink that made contact with the back that has been removed. Sorry I can't give you any yields, but I don't see how you can go wrong processing everything that has gold on it as this is obviously no cheap assembly. Hope you have fun with it.

FrugalEE


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## lazersteve (Jan 29, 2011)

The board plating looks thick, but it's ultra thin. After depopulating a quick bath in a wide flat Tupperware dish of Acid Peroxide with a tooth brush will leave you with a copper back in a few minutes. You won't see any signs of gold in the AP aside from some very fine black and dull gold colored specks from the gold plating. The gold is applied to the board using a technique that allows for very thin coatings. Get a normal pencil eraser and erase a small spot on the gold back, you'll see copper in one or two strokes.

The components will process nicely in the sulfuric stripping cell and should give you a fair yield.

It will be a lot of work, but you may get a fair sized BB out of 25 or more of these boards. All of that will come from the plated components.

Steve


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## poet (Jan 29, 2011)

Took a clean #2 pencil eraser and a clean square eraser (daughter apparently does no homework) and could not get copper. Took a screwdriver and scratched it up, still gold color. Took a razor and pealed a corner back. I can see the copper layer, but the gold is at least twice as thick. We'll see. When I get to that point I will do a few batches of a few boards each and compare averages.


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## lazersteve (Jan 29, 2011)

If you have access to an old toothbrush, a small amount of HCl, and some 3% peroxide you can confirm the plating thickness of the board quite easily. Nip off a 1/2" square of the corner where there are no components and process as I have described. If you don't see a consistent 1/2" x 1/2" loose foil floating freely in the AP solution, the plating is ultra thin. If you get a consistent 1/2" x 1/2" free floating foil in the solution you are right about the thickness. 

I've seen (and own) a wide variety of these types of boards with the gold backs. All of them are flash plated at best. From an engineering perspective it makes no sense to coat a layer of copper with a layer of gold twice as thick as the copper. 

Hopefully the boards you have are thickly plated. If they are, they'll be the first communications boards I seen that are.

Keep us posted.

Steve


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## kdaddy (Jan 30, 2011)

The 2nd post 2nd and 3rd pic are sweet little items. The white ceramic contains beryllium so don't crush. The caps are glued on so I
gently heat with a torch and it will slide off revealing lots of gold bonding wires. I scrape them off with an exacto or razor blade on to
a large peice of construction paper. It adds up quickly and its 99.99 gold, the rest is recovered in the cell along with the RF connectors. Do yourself a favor, cherry pick the good stuff, and sell the rest of the boards on ebay. I have tried the AP route on 25 boards and ended up with very little gold. , Keith


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## goldsilverpro (Jan 30, 2011)

poet said:


> The back of the board seeming has thick plating which I'm guessing is in the neighborhood of 100μ as it's as thick as a normal piece of paper.



In electronics history, there has never been 100 microns of gold plated on anything. Never, ever!!! It would not only be stupid, it would technically be very difficult to do, plus, it would have to stay in the plating tank for about 10 hours and the company would have wasted $54 worth of gold/sq.in. There is probably nothing with even 10 microns of gold on it. The most you will probably ever see is 2.5 microns, and that's rare, rare, rare. Most stuff, like fingers, pins, etc., runs about 0.5 to 0.75 microns. For the stuff you're talking about, think about 0.12 to 0.25 microns.


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## poet (Jan 30, 2011)

goldsilverpro said:


> poet said:
> 
> 
> > The back of the board seeming has thick plating which I'm guessing is in the neighborhood of 100μ as it's as thick as a normal piece of paper.
> ...



I should've been more specific. I did not mean microns, which is μm. I intended to say microinches, μin. Paper is around 50-100 microinches, which is also mentioned.


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## patnor1011 (Jan 31, 2011)

Now tell me one thing. How old are you? 
What was so offending that you decided to edit and remove your posts on this thread? You came here asking question and if you cant take other people advices or explanations just leave. Do not leave mess after yourself. 

I am for one thing - do not let members edit their posts for at least first couple of months. They tend to join, ask, ask, ask and then, if they are not happy with answers or for whatever strange reason intentionally destroy thread and damage valuability of informations provided to them FREE OF CHARGE!

*edited - First two posts in this thread were deleted and replaced with Thank you. In your other thread you removed pictures so you drastically reduced value of info provided. Now THANK YOU very much.


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## goldsilverpro (Jan 31, 2011)

> I should've been more specific. I did not mean microns, which is μm. I intended to say microinches, μin. Paper is around 50-100 microinches, which is also mentioned.



Even Zig-Zags aren't that thin. The thickness of common 20# copy paper is about .004", which is 4000 microinches.


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## Lou (Feb 2, 2011)

Not only is this thread in the wrong place, the fact that the original poster removed the pictures and information prompting the discussion has negated the value of this thread.


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## Harold_V (Feb 3, 2011)

Lou said:


> Not only is this thread in the wrong place, the fact that the original poster removed the pictures and information prompting the discussion has negated the value of this thread.


Indeed it has ----and you are far more polite than I intend to be with this individual. If he so much as says one word wrong, he's out of here. If readers intend to behave like mindless children and find fault with everyone but themselves, they came to the wrong place. I fully expect adult behavior from the readers of this board. 

Harold


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## kdaddy (Feb 3, 2011)

In an effort to salvage this thread, here are some pics of the type of boards that were deleted by poet.


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