Chemical for circuit boards

[Tredsaw12]

Does anyone know of a chemical that will dissolve the green film that basically covers the whole circuit board, (besides the gold fingers)? I have a box of boards that have no copper. Under the green film, all of the traces are gold. If I can get that film off, these could be some valuable boards.

 

[Anonymous]

I do not know about chemicals, but, a rasp in hand drill works real good and has the benefit of making the pieces small so they process faster.

 

[Rag and Bone]

What if you cut the boards into strips and soak them in AP?

 

[Palladium]

:arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?t=30&postdays=0&postorder=asc&start=30

 

[Tredsaw12]

Hey "Palladium" thanks for that link. That's a very long and informative thread. After reading that, and doing a little research I think I have the answer - Methylene Chloride-Based Paint Stripper. Should be able to buy it at any hardware store.

 

[banjags]

methylene chloride is very toxic... It is not widely used anymore because of that. If you find a product that contains a large quantity of this chemical please post it.

Sodium hydroxide works well but needs and overnight soak. and is much easier to dispose of.

 

[Harold_V]

I may be mistaken, but I seem to recall that carburetor cleaner is (or was) a source of the solution, but as you alluded, it has largely been removed from the market, as have many of the other useful but hazardous chemicals. One of them that I miss the most is 1,1,1 trichloroethane.

Harold

 

[Rag and Bone]

Using chemicals to remove solder seems like using a sledge hammer to open a peanut. There must be a good mechanical method. Has anyone tried?

 

[Anonymous]

I would just take a sharp blade and score through the solder mask numerous times it will make the metal available to the acid.

 

[Harold_V]

Using chemicals to remove solder seems like using a sledge hammer to open a peanut. There must be a good mechanical method. Has anyone tried?

They're talking about removing the solder mask, not the solder, and, fact is, there is a solution, and it's dead simple. Incineration. No one seems to find it a viable option, in spite of the fact that it is customary to process e scrap by that method.

Harold

 

[Tredsaw12]

OK, I went to Lowes today, bought some paint/varnish stripper. It says main ingredient is methylene chloride. I will try it out tomorrow and let you know how it works. I'm pretty confident this will do the job.

 

[Rag and Bone]

Have fun with the by-product.

 

[pilotdan]

Does anyone know of a chemical that will dissolve the green film that basically covers the whole circuit board, (besides the gold fingers)? I have a box of boards that have no copper. Under the green film, all of the traces are gold. If I can get that film off, these could be some valuable boards.

Do a search for ULTIMATE GOLD RECOVERY PROCESS on eBay. I bought that ebook and although I have not tried it yet, I would say it sounds like it will work. I plan to get around to trying it soon.

 

[lazersteve]

The traces are only gold plated. They are copper underneath.

Sodium Hydroxide will remove the film after a few soak and rinse cycles. The soak cycle should be overnight.

Steve

 

[banjags]

In my experience just one soak overnight with a strong sodium hydroxide mix should do it... but the are some boards that seem to be totally resistant to sodium hydroxide. One type of old sound card I have ran thru a sodium hydroxide wash 2 times and it remains completely untouched.
Interested to see how the methylene chloride works...

 

[junkelly]

Soaking with sodium hydroxide:

Does the solder mask stay relatively solid (flakes maybe)? Turn gummy? Can it be filtered / decanted so the lye is able to be used again?

Thanks for your help,
-junkelly

 

[Tredsaw12]

Well, I tried the paint/varnish stripper w/ methylene chloride and it didn't do a damned thing. Although, something didn't seem right. I even put it on an old piece of wood that had been varnished and it didn't touch that either. Also, it didn't smell at all. Maybe it was bad, old and expired. The can even says use within 6 months.

Will return it and try again.

 

[banjags]

Soaking with sodium hydroxide:

Does the solder mask stay relatively solid (flakes maybe)? Turn gummy? Can it be filtered / decanted so the lye is able to be used again?

Thanks for your help,
-junkelly

Some chunks and flakes... some seems to be partially dissolved but I would think that you should be able to filter it through several coffee filters... not sure if it would continue to work for a second round as it seems to loose its punch by the next morning in my experience.

 

[Joe]

I've tried the methylene chloride. It didn't work for me either.

 

[Tredsaw12]

Well, I've tried every chemical I can think of and nothing worked. I even tried Fedron which has some nasty chemicals in it, used to clean and recondition rubber but would destroy most plastics.

There is a guy on ebay that's selling information on "how to remove the solder mask". I wonder if anyone here has tried that.