Removal of plastic boards

[kjavanb123]

All,

Just curios, is there any acids like oxalic acid to remove or dissolve the plastic portion of board which everything is connected to it, therefore, releasing all the components such as ICs, PCI cards, etc. That way they get sorted out for separate processing methods?

I have tried to use torch to melt some of the tin alloy at the back of boards, it melts the tin and plastic together, but the component on the board comes off easily. Once the big components are removed, we are left with a board containing MCCs, resistors and black ICs. which can be crushed and processed.

I thought about somewhat use hot water to soften the plastic part of board to remove the board components.

Thanks and regards,
Kevin

 

[philddreamer]

Kev, I understand that some members place some of the boards &/or soldered components in HCl, thus dissolving the tin & separating the chips.

Phil

 

[maynman1751]

Kev, I understand that some members place some of the boards &/or soldered components in HCl, thus dissolving the tin & separating the chips.

Phil

Kevin, that is how I remove ram chips. Soak the boards in HCl + H20 plus heat. The chips and everything else will fall right off and are solder free. Then rinse, dry and separate. Hope that helps. John.

 

[kjavanb123]

Thanks guys,

Just to clarify, you meant dilute HCL by saying HCL and H2O?

Regards,
Kevin

 

[maynman1751]

Thanks guys,

Just to clarify, you meant dilute HCL by saying HCL and H2O?

Regards,
Kevin

That's right Kevin! 2to1 HCl/water. John.

 

[kjavanb123]

Hi maynman,

I tried 2:1 hcl: water heated up near boiling, then using a dropper, dropped few of solution onto the solders on the back of the board, and nothing happened, so I assume you meant to boil the whole board in that hcl solution? wouldn't it effect other components such as MCCs or PCI card holders?

I added some sulfuric to the mix, and it foamed up once dropped on solders, but not much dissolved. I try to cut the board into smaller parts, and boil the back where it has solders in hcl:water solutions.


Regards,
Kevin

 

[Geo]

no need to boil. just warm. less than 100 degrees C will work. what i do is put whole boards that will fit in a bucket and add dilute hcl to it and place it in direct sunlight. if the boards are too big to fit, i cut them in half. after a few minutes, you will see bubbles of hydrogen being evolved. the dilution can be as high as you can go and still get action on the solder. the more diluted, the longer it will take. also the more its diluted, the less of a chance of dissolving something into solution, like plastic or tantalum capacitors. it takes patience. you can dilute the hcl to any ratio with water and still get the same effect. normally to digest solder to clean boards, i mix a ratio of 3 parts water/ 1 part hcl. if i want 3 gallons of solution in a 5 gallon bucket, its 3 quarts hcl to 9 quarts water. that works in a days time pretty well if you put it in the sun. you can dilute it more and leave the boards in the solution longer, 2-3 days.

 

[maynman1751]

Hi maynman,

I tried 2:1 hcl: water heated up near boiling, then using a dropper, dropped few of solution onto the solders on the back of the board, and nothing happened, so I assume you meant to boil the whole board in that hcl solution? wouldn't it effect other components such as MCCs or PCI card holders?

I added some sulfuric to the mix, and it foamed up once dropped on solders, but not much dissolved. I try to cut the board into smaller parts, and boil the back where it has solders in hcl:water solutions.


Regards,
Kevin

Follow Geo's reply to you. He's spot on, as usual! Except for the dilution ratios, it's pretty much what I would have told you. I usually use the stronger ratio to hasten the process. John.

 

[kjavanb123]

Geo,

Thanks a lot, I just put a piece of board in 3:1 h20:hcl on a hot plate on medium heat, and after 30 mins most of the solders are gone.

Regards,
Kevin

 

[maynman1751]

Leave it 'cook' till it quits fizzing.