3
$\begingroup$

I'm trying to reclaim the metals on circuit boards and the vast majority is underneath the plastic coating. It is a brittle plastic that chips off in small flakes when etched but that process will lose to much of the precious metal.

$\endgroup$
2
$\begingroup$

This seems to be a popular question judging from some Google queries.

Printed circuit boards are made of a variety of materials, and from what I understand, the specifics may vary somewhat based on the specific needs of the product and the manufacturer. For example, in some cases, I know the PCBs are coated with special anti-static coatings to prevent delicate RAM and CPU chips from being damaged (e.g., this article found via Google among others).

So I doubt there's a definite solution - more likely you'll need to try several different things.

That said, there's a recent article that looks very interesting about separating parts by dissolving and swelling the plastic resins with DMSO: "Dissolution of Brominated Epoxy Resins by Dimethyl Sulfoxide To Separate Waste Printed Circuit Boards" Environ. Sci. Technol., 2013, 47 (6), pp 2654–2660.

Certainly DMSO is considered a near-universal solvent and will swell many polymers. So I'd probably try that first.

$\endgroup$
  • 3
    $\begingroup$ The usual precautions for DMSO apply. It quickly penetrates the skin barrier, as does everything that's dissolved in it. $\endgroup$ – Abel Friedman Oct 13 '14 at 16:08
  • $\begingroup$ @AbelFriedman Yes, very good point. Since it's a universal solvent, it's tricky to work with safely. DMSO will penetrate latex or nitrile gloves quickly. I usually recommend double gloves, which gives you sufficient time to remove the gloves before the DMSO contacts your skin. $\endgroup$ – Geoff Hutchison Oct 13 '14 at 16:18
  • 1
    $\begingroup$ I've not tried with solder mask, but DMSO or N-Methyl-2-pyrrolidone work great for stripping most photoresists. The trick is, you generally need to heat them. If you keep it under ~80 °C, it's safer because it's under the flash points of the solvents, but something like 130 °C works quite well. $\endgroup$ – Michael DM Dryden Oct 13 '14 at 18:22
-1
$\begingroup$

You might try Citristrip, which actually strips paint, but mine tipped over and spilled on a rather thick plastic packaging piece, and melted it over the course of a weekend. Benefit: Non-toxic.

$\endgroup$
  • 1
    $\begingroup$ Welcome to chemistry.SE! If you had any questions about the policies of our community, please ‎visit the help center. Could you be more elaborate about what this "Citristrip" is? This is considered a low quality answer in our community. $\endgroup$ – M.A.R. Jul 1 '15 at 23:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.