Benjaminza
Active member
Can you guys plz tell me if it is possible to depopulate small boards especially with LEDs, resistors and mlcc's on with ap solution.
Can I use ap solution to depopulate
- Thread starter Benjaminza
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Yes, but that will also take the Copper.
HCl will take only the Tin.
Benjaminza
Active member
Can you recover the copper later on? Do you mean as in a dilute HCI solution? Is it not a good thing if the copper is put into solution so early in your chemical proses?
No ordinary full strength.
And yes or no depending on the board and components.
If there are Gold plating/fingers you want to depopulate and remove solder first and then do AP after to dissolve the Copper and release the foils.
Benjaminza
Active member
So best way to depopulate is either mechanically or heated?
Fastest at least, and most of the time most practical.
There are many ways to do it.
Benjaminza
Active member
Im an avid follower of omegageek64 on youtube and in one of his videos he mentioned the hazards of ashing your chips without feeding extra air into the chips. Something about carbon absorbing the gold. Can anybody explain that to me plzzzz.
If you don't incinerate integrated circuits completely, there will be carbon left from their plastic bodies. You need a lot of air to fully burn the carbon off completely.
When you dissolve your gold, any remaining carbon can adsorb and absorb gold. So, when you filter out the undissolved bits prior to dropping your gold, a bit of gold will remain with the carbon bits.
Dave
When you dissolve your gold, any remaining carbon can adsorb and absorb gold. So, when you filter out the undissolved bits prior to dropping your gold, a bit of gold will remain with the carbon bits.
Dave
Benjaminza
Active member
Ok so I then need a compressor too.
A compressor is always nice to have, but why do you need one in this discussion?
For bubbling air it is enough with an aquarium air pump, cheap and effective.
Proper ashing can be done also without the air compressor, and incineration is best done (in my opinion) without the burner, but with good power heatgun. I explained this few times here already.
Carbon start to burn at appreciable rate even at 450°C. Heatgun can go up to 650°C, and that is more than enough. If you spread the material in a way air can get through the layer, you can incinerate easily and conveniently. Stainless steel mesh or stainless mesh basket is the thing of choice.
But back to the main toppic - yes, you can conveniently de-populate boards with HCL itself. No need for AP. Drawback is - you will produce liquid waste containing at least tin and lead. And that need to be dealt with responsibly.
If you want to do this on larger scale, heated depopulators which melts the solder and knocks off the components are way to go. Nasty outgas tho... Also need to be considered and managed by some afterburner or similar thing.
Carbon start to burn at appreciable rate even at 450°C. Heatgun can go up to 650°C, and that is more than enough. If you spread the material in a way air can get through the layer, you can incinerate easily and conveniently. Stainless steel mesh or stainless mesh basket is the thing of choice.
But back to the main toppic - yes, you can conveniently de-populate boards with HCL itself. No need for AP. Drawback is - you will produce liquid waste containing at least tin and lead. And that need to be dealt with responsibly.
If you want to do this on larger scale, heated depopulators which melts the solder and knocks off the components are way to go. Nasty outgas tho... Also need to be considered and managed by some afterburner or similar thing.
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Agreed. I’m just a small time backyard guy so my experience comes from that. I’ve used straight ~32% HCl and also AP to depopulate. Straight HCl will loosen components quickly but you can’t leave it for long time or it will start dissolving copper also. You also can’t leave it for too short of a time. Or you’ll be removing some components, but not all because it takes a bit longer, in my experience, for the “through hole” components to loosen. It takes more time for those components than the surface mount devices. I tried to get all components, so in my situation I wound up working with the acids in my hands a lot more than I should have. You can wear all the gloves and all the masks that you want, and they are mandatory, but you’re still going to expose yourself to the acids and the fumes in a backyard scenario. And it makes waste so you must give thought to what to do with that next.
Using AP to depopulate just made a mess for me. I had foils mixed with SMD components mixed with circuit board mask pieces (AARGH!!) and it just made a mess. I also couldn’t tell inductors from tantalum capacitors because all markings were also removed. Ultimately a great deal of effort is made trying to sort the smalller components. I do not advise AP. I do recommend mechanical separation. I also recommend sorting while you are separating, because you’re going to spend the time anyway, sorting through piles of components. Being well organized and being able to sort while I was deppopulating saved me time overall.
Forgive me, but I make the assumption that you’re just starting on this recovery journey. My advice for anyone just starting out, is to only use acids when they are absolutely necessary, and use as few as possible.
Using AP to depopulate just made a mess for me. I had foils mixed with SMD components mixed with circuit board mask pieces (AARGH!!) and it just made a mess. I also couldn’t tell inductors from tantalum capacitors because all markings were also removed. Ultimately a great deal of effort is made trying to sort the smalller components. I do not advise AP. I do recommend mechanical separation. I also recommend sorting while you are separating, because you’re going to spend the time anyway, sorting through piles of components. Being well organized and being able to sort while I was deppopulating saved me time overall.
Forgive me, but I make the assumption that you’re just starting on this recovery journey. My advice for anyone just starting out, is to only use acids when they are absolutely necessary, and use as few as possible.
Benjaminza
Active member
Yes I am only starting now. I think I watched almost every video on youtube at least 5 times. Dud recovery in my mind probably 3 more times but to be honest was still soooo overwhelmed with my first attempts.
First time I got a positive stannous test I wanted to cry lol.
I do though have a fume hood and foundry furnace. I have been prepping for a few months.
I do appreciate any and all advice. Ill definitely be watching this post for any other tips.
Thanks guys
First time I got a positive stannous test I wanted to cry lol.
I do though have a fume hood and foundry furnace. I have been prepping for a few months.
I do appreciate any and all advice. Ill definitely be watching this post for any other tips.
Thanks guys
Benjaminza
Active member
I have a air bubbler. I meant a compressor for pumping air into the bottom of my crucible while incinerating my chips to avoid carbon.
coincard
Active member
If you are just depopulating the boards why not just place them on a hot plate for a few minutes ? I do it all the time, the soldier heats up and everything just pops off the board....
Benjaminza
Active member
Only heat source I have available is my foundry furnace and frosty t burner
mikeman001
Member
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- Jan 23, 2018
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- 12
I've been recovering and refining for about 6 years now. I can promise you that a decent percentage of the videos on you tube are either misleading, or steps are left out, or are not logical, as far as some are completely bs. Read hokes book, I'm sure you can find it on this forum with ease.
I hear you there..seems a lit are just click bait
