Non-Chemical Removal and separation of bromine epoxy resin

[anotherbeginner]

First, I have to just put it out there that I am recently new to scrapping. I have been collecting mostly ram sticks with a few other assorted gold fingered and gold content items. I am still in the collection stage (amassing a good pile to work with) and have begun depopulating the the sticks of their IC's and MLCC's. During which I noticed on some of the ram, there are several gold contact points. I got curious and attempted to use my dremmel tool with a wire wheel attachment to scuff the green epoxy coating to see what was underneath. The wire wheel was just too well used and it didn't work very well so I tried again with the cutting disc attachment. Success! There is a blanket of gold under that green epoxy layer. So further searching took place and I found little to no information on a good method to get that epoxy removed. Until... I found this information... http://www.sciencedirect.com/science/article/pii/S0956053X15003712

I am hoping that one of the experts here can check this out and post a reply with thoughts about this method.

I am going to try to include a photo of the ram stick that I scratched up.

Any thoughts?

Thanks!

 

[Pantherlikher]

Hi anotherbeginnerand welcome to the forum which will give you the most valuable knowledge money will never be able to buy.

Here, you will processes and tricks to do things you never imagined...
As long as you read and research.

Most boards with that green covering only have copper under neath. Very few types of boards would hide gold under it but there are some.

In the google search box here in the forum...search fingers, gold fingers, green board, just about anything you might need to research.

First though we ask that you start at the welcome in group of posts.

Covers most stuff new people ask as well as how the forum is run and what's expected.
It will also guide you into the world of PMs(Precious Metals). Where to find, collecting, concentrating, and finally refining to get as pure a metal as possible.

The pile you have so far is a good start but to hold a finished piece of gold, silver, etc. in your hand, you will need to at least double or more of that pile. Concentration comes in and teaches you what, where and how to only save what pieces might have PMs.

Good luck
We all have started somewhere and ended up back to the beginning as it's the best way to learn and let things sink in, like learning patience which is most important of anything you could ever possibly learn.

B.S.

 

[g_axelsson]

That looks like copper to me. Do a search for "removing solder mask" and you will find a lot written here on the forum. The article you refer to talks about dissolving the plastic that holds the PCB together, not the solder mask.

A razor blade held slightly wedged but perpendicular to the surface is a good and fast version for testing what's below the solder mask.

Göran

 

[anotherbeginner]

Thanks for the welcome. Navigating this site seems a little challenging too as I seem to have completely missed the welcome section you refer to. Alas, I will go check that out.

 

[anotherbeginner]

That looks like copper to me. Do a search for "removing solder mask" and you will find a lot written here on the forum. The article you refer to talks about dissolving the plastic that holds the PCB together, not the solder mask.

A razor blade held slightly wedged but perpendicular to the surface is a good and fast version for testing what's below the solder mask.

Göran

You may be right about the copper. But I took the photo with my phone camera. It looks more like gold when looking at it in person though. I will look into this more. Thank you for your help and tips.

 

[bswartzwelder]

From the photo, there is an obvious color difference between the scraped surface and the gold plated finger contacts. This would tend to prove that it is not gold under the solder mask. It has been stated on the board many times that people will not plate with gold where it is not needed. Plating with gold and then covering it up with solder mask is an expensive process and actually serves no purpose.

Now that I've said that, there are many boards out there which do have a lot more gold than is necessary. The government is notorious for plating many area on circuit boards that will be used in the military. Boards on satellites may also have a lot of added plating on them as do many types of communications boards. Keep studying, grasshopper.

Good luck.

 

[nickviman]

this is a very useful abstract in regards to de-brominating epoxy

In the present study, an effective and benign process using sub- and supercritical water (sub/SCW) to simultaneously degrade brominated epoxy resin and recover metals from WPCBs was developed. Experiments were performed in a batch-type reactor with temperatures ranging from 200 to 400 °C, water adding amounts from 10 to 40 ml and holding times from 30 to 240 min. The results showed that brominated epoxy resins (BERs) could be quickly and efficiently decomposed under sub/SCW condition. The debromination rate was 97.8% by controlling the temperature, water adding amount and holding time at 400 °C, 40 ml and 120 min, respectively. Most of the bromine was changed into HBr and around 97.7% was enriched in water. Meanwhile, bromine-free oil was obtained of which the main compositions were phenol (58.5%) and 4-(1-methylethyl)-phenol (21.7%). After the sub/SCW treatments, the glass fibers and copper foils in the residue can be easily liberated and recovered respectively. The copper recovery rate reached 98.11% in the purities of 96.74% (grain size >2.0 mm) and 92.74% (0.147–2.0 mm).

reference http://www.sciencedirect.com/science/article/pii/S1385894713000041

I also heard that a hot lye solution will strip most solder masks through YouTube channel (moose scrapper)

the former method is something I will likely try in the near future as it is apparently extremely efficient and can keep my parents sane because the main reactant is water :mrgreen: