# My First Batch, Touchpads



## cvillan (Jun 3, 2012)

So, I've been lurking on the forum for quite a few months, learning as much as I can. I've read and reread Hoke and have finally started on my first batch. I get a pretty steady supply of computers from my job and have been cherry picking the parts I think would be the easiest and most fun to work with.

I decided to start with a small batch of touchpads because A: I don't want to mess up a large batch and B: there's gold everywhere! TI started with 17 touchpads with the tops pealed off weighing in at 172 grams. After a soak in in goofoff and stripping the components off the back they totaled 111 grams. Then after a quick re-watch of lazersteve's video of solder mask removal and suiting up in safety gear I stripped off the solder mask. Weight now at 109 grams.

I was getting ready to soak them to remove the last of the solder but ripped a glove after the solder mask removal so that'll be on hold till tomorrow. After this batch is done I'll be getting started on LCD boards.

Thanks to everyone! Without the knowledge I've gotten on this board I would never have been able to do this. If you have any pointers or tips, let me know!

Heres how they look now.


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## Smack (Jun 3, 2012)

Seems like you've got it covered pretty good so far. You going to let us know what you get in foils? I've never done any touch pads before, they've always went in the gaylord box.


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## cvillan (Jun 3, 2012)

Will do. I made time tomorrow to pick up gloves and hopefully I can find a scale that does better than whole grams.


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## gold4mike (Jun 4, 2012)

I bought one of fleabay a week or two ago that weighs in grams to two decimal places. It was about $17.00 delivered.


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## Marcel (Jun 4, 2012)

I did some touchpads a while ago, just like you did. Some have a very thin gold layer, but some others had layers thick just like the memory goldfingers, so yield was good after all.
I think those from elder notebooks are the ones that have the thicker plated gold on them.


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## cvillan (Jun 4, 2012)

I should be out of work here in an hour or so. Picked up some SMB at the homebrew store at lunch and stopping on the way home for new gloves. The fun continues tonight!

gold4mike: Good idea, just ordered one that should arive Thursday. Saved me a trip to the head shop and I try to avoid that part of town.

Marcel: Most of these came out of Pentium 2-4s but the one in the top left of the picture came from an old 486. It stood out because it has a solid sheet unlike the others and the solder mask on it was a nightmare to get off. Also, it has a deffinate matte finish to it unlike the rest. My problem is I'm partialy color blind and have a bit more trouble telling gold from copper than most. Hopefully it has some nice thick plating on it. I also got a rather interesting processor board out of that laptop I need to get a few pictures of.


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## cvillan (Jun 5, 2012)

Got home a little early last night and started soaking the touchpads to remove the solder. All the solder was removed in just a few hours so I started in the AP Solution. This morning the color I can only describe as a half full bottle mellow yellow someone had been using as an ashtray for a few months. But there was gold floating on top! A little swish brought many more off the touchpads to the top. To bad I was running late and didnt have time to inspect it more. Tonight hopefully I'll have time for pictures.


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## Lobby (Jun 5, 2012)

I like the way you're being methodical and analytical about this experiment.


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## cvillan (Jun 6, 2012)

Thank you Lobby. I figured I need to keep track of every step of the process, 
A: so I can know my estimated yield on future runs and
B: if I have a huge difference in my numbers on another batch I'll know I messed up and hopefully can use the information to figure out where.
Also if I have the info I'm going to share it here because without this forum I wouldnt even be doing this.

So last night after work I checked in and thar be gold in me bucket! I did notice some are stripping off faster than others. I had warped the touchpads before throwing them in the AP solution so they wouldnt lay flat on each other but apparently a few flattened back out and they were sticking to eachother. Does anyone know if the chemical reactions going on may have caused that? Or maybe I just need to bend them up a bit more next time. I moved them around a bit to expose the areas that had been covered. 

Also there is a little bit of dark sludge accumulating at the bottom. It looks to me like dark brown or black. I'm going to ask a friend whos eyes have the whole color thing down to check it for me. If I read correctly this should have gold and I need to treat it together with the foils?

But over all I think its looking wonderful.


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## lazersteve (Jun 7, 2012)

The solution looks very light yellow green to me. Have you tested it with stannous chloride yet?

Don't add any more oxidizer to the solution and it should saturate with copper on it's own cementing any dissolved gold back out.

Steve


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## cvillan (Jun 8, 2012)

lazersteve: I thought the color was off. I'll definitely test it tomorrow after work. Your videos have been invaluable in my learning. Without them I'd just be drooling over circuit boards.


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## cvillan (Jun 8, 2012)

Today there was a little dark muddy stuff at the bottom. Tested with stannous chloride. Definitely gold in my solution. The touchpads are just blank PCBs now. No gold or copper left on them at all. My preliminary plan is let is sit for a day for more gold to fall. Should it still test positive I'll drop in a piece of copper. But before any of that, its time to read, watch videos, scour the forums, and watch Prometheus, just to make sure I'm not messing anything up any more. Sometimes when I have a problem thats confusing and frustrating I just need to walk a way for a bit and clear my mind before coming back to it.


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## cvillan (Jun 11, 2012)

Sorry for the lack up updates, but my internet time has been taken up lining up a place to move at the end of summer. Heres what I've been up to the past few days.
I let the AP solution sit for another day. It tested with negative with stannous chloride. I filtered the AP solution and got mostly dark mud but a few pretty gold specks in it. So small I couldn't even see the shapes, just a glint of light. Washed 3 times in HCL and dissolved in HCL/CL. Letting it evaporate and tomorrow I should have an answer. I'm guessing a small fraction of a gram. Maybe 0.2. Its so little I'm planning on weighing a filter dry and after precipitating and filtering the gold off letting the filter dry and weighing it again. But any gold is still more than I had and now that I know I can do this I'm starting my LCD Controllers(just over 700 grams). I'll make a separate post of weights throughout the process for an accurate yield. Eeee! I cant wait for tomorrow for a final total! *excited*


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## ericrm (Jun 21, 2012)

is it ok to ask you how it ended up?


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## Marcel (Jun 21, 2012)

I cannot answer you how his run ended, but with touchpads one should roughly calculate that 1g gold can be plated over a maxium of 1 square meter.
1 touchpad is around 7 x 5 cm = 0,35 sqm. That means, about 30 pieces should yield around 1 gram. (theoretically, minus losses in the process).
He used 17 touchpads, so one should not expect a bit less than 0,5g if everything went perfect. My guess is around 0,3g.


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## ericrm (Jun 21, 2012)

Marcel
to your knowledge ,does touch pad plating fall in the same categorie than other full gold (under the mask) plated riser board?


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## patnor1011 (Jun 21, 2012)

I tought that 1 g of gold can be hammered to 1 square meter, I do think that when plated electronically then 1 g of gold will be sufficient to much more than 1 square meter.


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## Geo (Jun 21, 2012)

http://en.wikipedia.org/wiki/File:Small_gold_nugget_5mm_dia_and_corresponding_foil_surface_of_half_sq_meter.jpg


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## cvillan (Jun 22, 2012)

Sorry for the delayed response guys. Lifes been hectic but I did manage to save my house from forclosure!

Total yield was .08 grams. I did notice in the whole process that the touchpads I pulled from pentium 2 to core2duo laptops came off as a near powder. The gold from one from an older systems touchpad came off in large flakes but they broke up easily when agitating the batch.


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## Smack (Jun 22, 2012)

Just the difference in thickness.


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## g_axelsson (Jan 5, 2013)

Marcel said:


> I cannot answer you how his run ended, but with touchpads one should roughly calculate that 1g gold can be plated over a maxium of 1 square meter.
> 1 touchpad is around 7 x 5 cm = 0,35 sqm. That means, about 30 pieces should yield around 1 gram. (theoretically, minus losses in the process).
> He used 17 touchpads, so one should not expect a bit less than 0,5g if everything went perfect. My guess is around 0,3g.


I'm not saying anything about the area one gram of gold could plate, but the number of touchpads per square meter is off.
7x5 cm = 0.07x0.05 m = 0.0035 m2 which gives 1/0.0035 = 286 touchpads per square meter.
If gold plate covers both sides then it becomes 143 touchpads for a square meter of gold plate.

Göran


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