Non-Chemical Question on Depopulation of boards MASS style

[drlonzo]

First and foremost I want to thank everyone that has posted in this forum with their valuable knowledge and unique problems. It makes for some great reading. I'm new at this new age PM mining, however i've managed to find most of what I wanted and needed to know by reading HOKE and on the forum. I've now started to actually start removing some of the components from the boards that i've amassed over the last little while. So far i've been primarily been using the mechanical and heat methods by pulling loose what i can and using a heat gun to melt solder etc. I'm wondering if anyone has or is using HCI by itself to remove components after removal of the caps and major metal connectors. I'm sure it takes time without heat but does anyone use it to any degree :?:

 

[chlaurite]

I recently tried it on a batch of mixed boards (a few MBs, some PCI, some RAM, even a single CPU to see if I could get its pins to drop off a bit easier).

At first, it looked simply beautiful - Chips popped right off, quite a few of the MLCCs dissolved except for the one part we want, the end caps (ie, "good"). Everything looked like "why doesn't everyone do this to every board they get?"

Then I started cleaning up...
Decant acid: Check.
Rinse boards: Check.
Soak boards for a while to remove any stray acid so I don't hurt myself later: Why does my soak-water look like milk???

Basically, using HCl to depopulate boards amount to removing mostly lead, some tin, and a few other highly reactive metals (magnesium, zinc, aluminum, etc). That means you end up with lead soup, more-or-less (or tin soup for newer ROHS boards). Lead, funnily enough, makes a complete mess out of just about everything we do. Good to get rid of, bad to actually get rid of.

I would only use this approach again with small, densely-packable boards, like RAM. With mixed boards, the sheer volume of fluid involved just leaves too much waste liquid to properly handle. I currently have a five gallon bucket 2/3rds full of "milk" that probably won't evaporate down to something manageable before winter.

As an aside - Although the rest of the concept worked great, the CPU part of this experiment didn't work at all. Its pins stayed firmly attached, and in fact the gold on them ended up "hidden" by a light grey coating of unknown crap-metal.

 

[niteliteone]

Generally I use an old cast iron skillet with an inch of sand in it and place this on a propane stove outside. When the sand warms up. place your board on it and with-in a minute, with pliers I grab the board and tap it on edge against something solid and all the parts fall off.
With older through hole components you can actually pull them of while the board is still on the hot sand bed.
I know this is manual labor but for me it is faster and cheaper with a lot less waste to dispose of.

Hope this helps.

 

[chlaurite]

Out of curiosity, with the skillet method, don't you still need to deal with all the solder that comes off with the components? For all its shortcomings (time, labor, dulled utility knives), at least purely mechanical depopulation has the advantage of leaving virtually all of the solder attached to the motherboard.

Though I suppose it takes a lot less effort to snip legs off of an already-removed part than it does to get the part off the board in the first place, so still sounds like a net gain. I'll try your method this weekend!

 

[rickbb]

The only boards I bother to de-populate are older cell phone boards that have gold plate everywhere. (Old BlackBerry's are the mother load.)

I use the heat gun approach, clamp one corner of the board in a bench vise, get the heat gun going on it until the parts start to fall off, then scrape it with a wide blade putty knife. Works well.

Then soak in just Hcl to remove tin, lead etc. Then it's ready for AP.

Other boards I sell as is and let someone who's more set up for them make a few bucks.

 

[niteliteone]

Out of curiosity, with the skillet method, don't you still need to deal with all the solder that comes off with the components? For all its shortcomings (time, labor, dulled utility knives), at least purely mechanical depopulation has the advantage of leaving virtually all of the solder attached to the motherboard.

Though I suppose it takes a lot less effort to snip legs off of an already-removed part than it does to get the part off the board in the first place, so still sounds like a net gain. I'll try your method this weekend!

You are somewhat correct, as the solder is in both places (the board and the components) but is makes for a much simpler form of scrap to run through the various processes and allows for a much easier way to recover more values overall with less waste to deal with.
IC's, capacitors, resisters and all the base metals are easily separated from each other and can easily be dealt with using simpler processes that work best with each type of scrap, thus saving time and waste by-products that require more time and money to dispose of.

 

[NobleMetalWorks]

You can also shear the components off boards using a press.

Place two pieces of case hardened steel close together, spaced about the distance of an average PC board thickness.

Build a table above it, with a slot cut the length, and the width wide enough to accept a PC board with components.

Design the table so that it holds the metal at a distance under the table top with the slit in it, with enough room so the components can fall off the sides of the metal

Buy a cheap press from Harbor Freight, or get one somewhere else, used, new whatever works.

On the head of the press, use some type of rubber material so as not to crush the PC board, place the press so that it is directly above the slit in the table, and the two pieces of case hardened steel under the table top.

Load your PC board with the components into the slot in the table top so that it rests on the metal underneath

Lower the press onto the edge of the PC board, as you do you will find some resistance, keep pushing through the resistance and the components will start to be sheared off the board.

Once you have a little over half the board cleared, flip it over and start from the other side.

The components will fall into your 55 gallon trash can, and you can put the board aside to be processed for it's values.

This works fairly quick, is efficient, you don't have to worry about fumes, fires, acids, etc.

Scott

 

[chlaurite]

I like the shear idea, but wonder - Do you get the SMCs (like MLCCs) also cleanly removed, or do they just end up crushed to dust?

It sounds almost too good to work. Still, worth a try - Now to find a suitable press!

 

[gold4mike]

There is an old post with a picture of a board scraper. Do a search for "Franken" and you'll find the Franken-Scraper.

 

[justme2]

Has any one ever tried a Plane ?

 

[kurtak]

Has any one ever tried a Plane ?

:shock: :shock: :shock:

I assume you are talking about an electric planer used for planning a piece of wood

I hope not - you are going to have sharp shards of metal & plastic flying everywhere (stand back - it sounds bloody to me) & you are going to ruin the planer blades in a heart beat :!: :!: :!:

Kurt

 

[Geo]

Theres too much beryllium copper involved to create that amount of airborne particles. Once beryllium gets airborne, it can travel to your lungs where it causes the most damage. Look up beryllium hazards.

 

[sharkhook]

I have started using a 3 inch wide, heavy duty paint scraper with a handle made for tapping with a hammer. I line it up, and hammer at it with a soft plastic mallet. Pretty quick, at least quicker than the flush cutting side cutters I used to use. Cut a hole in one end of the lid on a large plastic container propped on an angle, insert the board, go to work on it. Not the best, but an improvement over my old way, one piece at a time.

 

[nebiconezer]

The only boards I bother to de-populate are older cell phone boards that have gold plate everywhere. (Old BlackBerry's are the mother load.)

I use the heat gun approach, clamp one corner of the board in a bench vise, get the heat gun going on it until the parts start to fall off, then scrape it with a wide blade putty knife. Works well.

Then soak in just Hcl to remove tin, lead etc. Then it's ready for AP.

Other boards I sell as is and let someone who's more set up for them make a few bucks.

hello, I'm new here and am drinking in all the info I can...this will seem silly I know, but when you say "ready for AP" what does that mean?

 

[FrugalRefiner]

AP = A/P, Acid Peroxide, Copper II Chloride, CuCl₂.

It is a combination of hydrochloric acid and hydrogen peroxide typically used to remove copper base metals from gold plated items. You can search some of the terms above for more information.

Dave

 

[richoc]

Use heat gun on back side until the solder is flowinig smack it against a brick in a large metal
Cooking sheet back side down.
Do not burn the broad too hot, you need to do this to learn it.
This will collect most of your solder.
Now re heat smack in to second set up component side down and they will all fly off.
Repeat until you have collected all the solder you can.

Not going to help you learn you need to do.
East gloves a eye protection.

 

[Ashaman]

You can also shear the components off boards using a press.

Place two pieces of case hardened steel close together, spaced about the distance of an average PC board thickness.

Build a table above it, with a slot cut the length, and the width wide enough to accept a PC board with components.

Design the table so that it holds the metal at a distance under the table top with the slit in it, with enough room so the components can fall off the sides of the metal

Buy a cheap press from Harbor Freight, or get one somewhere else, used, new whatever works.

On the head of the press, use some type of rubber material so as not to crush the PC board, place the press so that it is directly above the slit in the table, and the two pieces of case hardened steel under the table top.

Load your PC board with the components into the slot in the table top so that it rests on the metal underneath

Lower the press onto the edge of the PC board, as you do you will find some resistance, keep pushing through the resistance and the components will start to be sheared off the board.

Once you have a little over half the board cleared, flip it over and start from the other side.

The components will fall into your 55 gallon trash can, and you can put the board aside to be processed for it's values.

This works fairly quick, is efficient, you don't have to worry about fumes, fires, acids, etc.

Scott

I know this thread is quite old - but I would like to see a pic of this setup if you have one please?

 

[Geo]

I don't think he has been on the board since Dec.25, 2013.

 

[hatemelborai]

I don't think he has been on the board since Dec.25, 2013.

Attached file explains how to remove all PCB's components

 

[g_axelsson]

Attached file explains how to remove all PCB's components

There's a patent to go with that. Maybe it gives some more details.
http://www.google.com/patents/US6641712

Göran