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  • Removing solder mask in circuit board

    In one of the video's Ben asked if there is a way to remove the solder mask from the circuit boards to expose the underlaying metals and see if there might be gold.
    I was wondering the same and went looking on YT. Found someone on a BBQ with lye and I thought sure why not let's try that out.
    Of course I first had to translate and find out what lye was, found the fomula (NaOH or Soda) also found in "plunger, unbocker" or whatever you call it (here's a link to amazon for the product I used https://www.amazon.co.uk/Destop-Turb.../dp/B00EBAFOBA since I couldn't find another with English discription(sorry about that)).

    So I went ahead and followed partially what he did.
    I heated up some water (about 500ml) to boiling point, put in the product, about 250ml and let the RAM in there for about 25min, no aditional fire was added at that point.
    Nothing changed visually, what a disappointment.

    2nd attempt
    Same procedure with 250ml water 500ml Destop and 25min later no changing. So I added another 250ml boiling water and waited again 25min. Nope toothbrush didn't scrape a thing off the RAM.

    3rd attempt
    NO water 500ml Destop 1h later, I begin to see a light green shine in the produkt but that's it.
    I let it sit in there for 3 days and was finally happy to see that after 3 days I could scrape of the solder mask with just a piece of wood.

    Now I'm waiting for the produkt NaOH to arrive so I can test that out on another board.
    And hopefully in the near future i'll have some other type of board's that i can test out since i heard the blue solder mask should be harder to remove.

    I'll keep you posted when I have more info about that.

    Cheers and have fun

  • #2
    I think the main problem is there's not much gold under solder masks usually, normally it's gold flashing (ENIG) which is very light plating and very low yield to make it worth the time spent.
    But still worth knowing how to remove the mask if you do find a board with heavy plating.
    Buying eWaste link here


    • #3
      Ok, LYE is also known as caustic soda here in OZ. I have posted a link to a video showing how it's done, the presenter says that this works on the majority of boards but he also says that some boards have a mask that is resistant to this method. Also note that he keeps a constant flame under the bath for the entire process. Cheers, Merv. https://www.youtube.com/watch?v=gZEe9kKgncc