Removing resin from an embedded circuit

Discussion in 'General Electronics Chat' started by cmartinez, Dec 3, 2014.

  1. cmartinez

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    Does anyone know a quick and reliable method to remove hardened resin from a circuit that's been embedded in it?
    I have this part belonging to a valve in a high pressure pump that I'd like to inspect (or dissect... I'm pretty sure that it's some sort of coil) but the thing has been cast in hard resin, and I'm trying to avoid spending innumerable hours doing archeological work with a chisel and a hammer and a brush just to see what's inside... I'm even considering x-raying the thing, if it comes to that...
     
  2. #12

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    Modern potting compounds have defeated every solvent I know about, even soft, grey, flexible foam.
    I have been relieved of the belief that, "If a man can assemble it, I can take it apart".
     
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  3. cmartinez

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    I'm gonna translate your comment as "sorry dude... I suggest you brew yourself some coffee and start digging"... thanks for your honest answer, though... *sigh* :(
     
  4. #12

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    Wait a while. There are smarter people than me on this site.
     
  5. RichardO

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    I too am curious about ways of doing this.

    Heat might help. Some epoxies soften at high temperatures.
     
  6. nsaspook

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  7. RichardO

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    I once asked a chemist how to remove polyimide (Kapton) from the top of an IC die.

    He replied that he had actually done this in a previous job! He said that I could use hydrofluoric acid. I pointed out that I did not think the IC would the acid and I really did not want to work with such a strong acid anyway. So, I asked, is there any other chemical that would work. Well, he said, "hydrazine". I decided that I could live with the polyimide where it was. (Hydrazine is a toxic rocket fuel :eek:).
     
  8. #12

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  9. cmartinez

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    I was considering that too... until I read spook's document warning on the dangers of releasing harmful vapors when heating some resins... Guess the first step would be to cut some samples from the part and dip them in different chemicals... see how they behave...
     
  10. #12

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    How many of those chemicals do you have in stock???
     
  11. cmartinez

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    Hydrazine!!! your friend's definitely a risk taker! I was once told that just by being a witness to a hydrazine leak happening a hundred meters from where you were would almost guarantee health problems in the long run... besides... one would need a chemical that doesn't attack the electronic components too...
     
  12. GopherT

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    For the hobbiest, the options are dwindling in the US. Most good solvents are under lock-and-key by the EPA or the DEA.
    You might have more chances in Mexico (OP is in Mexico if nobody noticed).

    I will send a list tonight.
     
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  13. cmartinez

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    None... but I'd be willing to buy samples to make tests, if I have to...
     
  14. cmartinez

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    What's OP ???
     
  15. djsfantasi

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    Original Poster
     
  16. cmartinez

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    oh.... thanks for clarifying...
     
  17. #12

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    That term is left over from a previous website version. This one calls you a, "Thread Starter".
     
  18. nsaspook

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    BR-549, #12 and cmartinez like this.
  19. BReeves

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    Can't remember the name of the chemical, when I was working for Hughes Aircraft in the 60's we used what was at the time a common degreaser. We would just drop the potted module in a jar and in a few days the potting material would be laying on the bottom in small chunks. There was a big vat of the stuff in the circuit board fab shop for cleaning boards. Sure wished I could remember the name even though whatever it was is probably unubtanium now.

    Found it Trichloroethane
     
    Last edited: Dec 3, 2014
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  20. cmartinez

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    The most common degreaser is ammonia... I doubt that would work in modern resins, though... I just remembered that diesel fuel attacks silicon compounds... melting them and making them rubbery after a while. Also, some oils eat through some plastics and epoxys ... I wonder if this could work for me, though... On the other hand, I have nothing to lose by submerging that thing in those fluids for a few days...
     
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