Methods of depopulating PCB's

mbflash

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Feb 21, 2011
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Maine
butcher said:
Remember the tin in solder will dissolve gold into it, making an almagam of tin and gold, even at temperatures as low as the melting point of the solder.

Free melted solder will also solder to other (unsoldered metals) before it will drip off.

So would i be better off cutting pins off than heating to unsolder them?
I would be using a cell for the pins.
Also Geo responded to a post by someone asking about treating pins with HCl pryer to going
to the cell he said something like not to bother.
Am i correct in assuming the small part of almagam (tin and gold) that part of gold would not be
recovered in the Sulfuric cell ?
 

kilo17

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Jan 11, 2013
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76
I use Steve's method with the AP. I save and reuse my AP several times and when I have accumulated to much from additions, I pour it off into a second bucket that I use to depopulate RAM boards etc... Here are a couple of pics from some I did this weekend.

image.jpg
image.jpg
 

total-resale

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Apr 20, 2013
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For the small timers, i found a medium size chisel is great but i dont use it as you would normally I place it beside them and twist my wrist, it is labor intensive but I do sets of components at a time so no sorting. IC's first, use edge of chisel to cut legs then use leverage from beneath, Caps and Res with the twist, can do a stick of ram in a minute and very little mess. Safety glasses as must (as should be normal) Had a tiny resistor fly up my nose and im not sure i ever found it =( now I wear a dust mask.
 

squarecoinman

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Feb 10, 2013
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140
danogarvin123 said:
Besides the obvious of de-populating PCB's for the IC's.......what other value is it? I only pull the IC's and pins off for future recovery...and then toss them into my pile for e-scrap. Am I missing some valuable recovery items?


Yes you are missing a few things, monolithic ceramic capacitors , tantalum

Use the search on the forum , it will be a good exercise for you and it will explain why you should keep the MCC and the Tantalum capacitors

scm
 

hatemelborai

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Mar 18, 2012
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The best method is to use fluoroboric acid and hydrogen peroxide to strip solder, the you can remove all components easily.
 

hatemelborai

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Mar 18, 2012
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patnor1011 said:
kazamir said:
hatemelborai said:
The best method is to use fluoroboric acid and hydrogen peroxide to strip solder, the you can remove all components easily.

Can you please elaborate on this process.

Better not to.

to strip solder, solution of fluoroboric acid 40% of 30-50 percent by volume and hydrogen peroxide 30% of 7-10 percent by volume and balance with water, heat the solution to 60 c. it will take about 4 hrs to remove the solder
 

Captobvious

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Aug 22, 2012
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208
Location
Omaha, NE
hatemelborai said:
patnor1011 said:
kazamir said:
hatemelborai said:
The best method is to use fluoroboric acid and hydrogen peroxide to strip solder, the you can remove all components easily.

Can you please elaborate on this process.

Better not to.

to strip solder, solution of fluoroboric acid 40% of 30-50 percent by volume and hydrogen peroxide 30% of 7-10 percent by volume and balance with water, heat the solution to 60 c. it will take about 4 hrs to remove the solder

Me thinks I'll just stick with my heat gun... much simpler... quicker too
 

patnor1011

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limerick
Yep, not to mention that above process just create additional waste stream needed to be dealt with. Heatgun allow you to collect solder which can be sold or used.
 

ldpolli

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Jan 9, 2015
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Very old subjetc, and i saw this in some website, is it possible working with pcb? Or ic's? Maybe dissolve epoxi?

Anyone knows anything about this? Already tryed?

http://www.ecycle.com.br/component/content/article/37/343-maquina-transforma-plastico-em-oleo-livre-de-co2.html
 

marlyn

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Aug 15, 2014
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Location
Sanmartin
Method 10: Thermal depolymerization

Does anybody have some experience with this process? I like the idea very much, but I'm not sure about economical part. Even in small scale production/own equipment. Not talking about 4MPa pressure and high temperature...
 

patnor1011

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May 22, 2008
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limerick
ldpolli said:
Very old subjetc, and i saw this in some website, is it possible working with pcb? Or ic's? Maybe dissolve epoxi?

Anyone knows anything about this? Already tryed?

http://www.ecycle.com.br/component/content/article/37/343-maquina-transforma-plastico-em-oleo-livre-de-co2.html


That kind of machine is nothing new. It is rather expensive and if you are going to buy it you will better stick to what it is designed for. It work with certain type of plastic only so I guess sticking printed circuit board in it will not be advisable and practical. I would compare that to ore crusher and coffee blender. Action look the same but you cant use one of them for both materials.
 

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