# Cell phone depopulating (ic's enclosure)



## byte-tech (Feb 19, 2015)

Good day!

I recently acquired some cell phone boards and i cant thing of a good way to remove those metallic enclosures on the boards. I tried a chisel but that is time consuming and there is 10kg of boards plus 100 more to disassemble . Do you have some ideas?
The rest of the boards are going to be depopulated by air gun or sand bath.


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## rickbb (Feb 19, 2015)

They are soldered on and the heat gun/sand bath will loosen them the same as other components.


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## Beirdo (Feb 19, 2015)

I've had great success at removing those with the hot air rework station running at 300C, same as removing components. You'll likely need to heat up an edge and pull it up with tweezers or needle nose pliers (I usually pry up with the tip of an xacto knife while heating). Of course, safety first, be sure to wear eye protection as flying metal shields can occur at times... once I have them off they go in my box of mixed metal which may some day be enough to take a scrap yard trip.

I think that on some cell boards these are soldered on using silver solder (and a lot of it) so it may be worth considering recovering the solder if you end up with enough quantity.

Edit: stupid phone automangled some words, sorry


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## byte-tech (Feb 20, 2015)

Thanks for the tips. 

i was planning to do the sand bath on Sunday but now I'm thinking....silver solder? sound like a time consuming work to recover the small balls of solder if you use an air gun, sand cant be that selective. Interesting? sure it is, worthwhile? don't know. I'm sure +-400 cell phone cards don't sound much for some of you, but for my "league" are a lot!  

Uresti

Edit: mispelled "can" ---> "can't"


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## g_axelsson (Feb 20, 2015)

Beirdo said:


> I think that on some cell boards these are soldered on using silver solder (and a lot of it) so it may be worth considering recovering the solder if you end up with enough quantity.


Beirdo, I think there is a misunderstanding or a slight error in your wording.

"Silver solder" usually means a hard brazing solder containing a large portion silver. Used for example in brazing copper tubes.

"Lead free solder" is a high tin solder with above 90% tin. These soft solders sometimes contains a few percent silver (usually around 3.5%) but not all do.

Lead free solder is used in all modern electronics built under the rules of ROHS (Europe 2003 - ) and similar environmental rule sets.

https://en.wikipedia.org/wiki/Solder

A high silver braze could be used in phones (and other electronics) but then it's inside components, for example silver palladium brazes used to fasten dies onto the lead frame in chips.

Göran


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## Beirdo (Feb 20, 2015)

I was specifically referring to solders that are around 93% tin and 7% silver, which I have heard commonly referred to as silver solder, although I suppose it's more properly silver-bearing solder. Thanks for helping clarify this. I definitely did not mean silver braze material.

Too easy to get confused, sorry.

As it is only 7% silver max, it would only be worth recovering if you had a decently large amount of it, I should think.


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## artart47 (Feb 20, 2015)

Hi there!
When I read your post I visualized a sand bath with some wires strumg accross it so you would have to slide the boards under the wires have a block of wood with a handle,( like a wood float I use for concrete work) But this one has harddrive magnets epoxyed on the bottom.
When the board is hot enough, tap the float on each board. the magnets should pull the metal shields and the wires should keep the boards in the sand. I believe the shields are iron.
Hope this helps! 
artart47


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## byte-tech (Feb 22, 2015)

artart47 said:


> Hi there!
> When I read your post I visualized a sand bath with some wires strumg accross it so you would have to slide the boards under the wires have a block of wood with a handle,( like a wood float I use for concrete work) But this one has harddrive magnets epoxyed on the bottom.
> When the board is hot enough, tap the float on each board. the magnets should pull the metal shields and the wires should keep the boards in the sand. I believe the shields are iron.
> Hope this helps!
> artart47



Thanks for the advice, but the things didn't went good enough. The shields came loose easily hitting the hot boards in the container, same as the IC's and most components like camera, connectors, etc. except the SMDs, more time in the sand and i ended with charred boards, less time and no single thing comes loose, less heat and takes too long and still the SMDs remains in the boards.
I will try some boards in diluted HCl, The first time i did that time ago and ended with a mess but was HCl 32%

Uresti.

Edit: Geo made things look easy: https://www.youtube.com/watch?v=Pn5LjwnmYFg


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## byte-tech (Mar 1, 2015)

I am ashamed, almost a year here and i have not learned the most important thing: patience. Today i tried again the sand bath, this time i changed the height and the quantity of sand, bingo! everything went good, not a single charred board and all components were striped, Too bad i can just do this on Sunday's mornings, going to take me at least 3 more weeks to finish all the boards, better late than never.  

Uresti.


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