Epoxy coating of a Printed Circuit Board removal is a tedious process. I tried with various organic solvents but couldn't remove it. I think there is some relation between the polar and non-polar components. I need a clear picture.
Epoxy resigns are cured in various method. Dissolution of cross-linked epoxy-coating depends on solvent, temperature, curator, curing method, degree of cross-linking density etc. You may get an insight about the dissolution of epoxy coating from the following, which I get from the https://en.wikipedia.org/wiki/Talk%3AEpoxy.
"In the pipe coating industry, the applied epoxy coating (rejected during QA/QC) is removed by burn-off at a temperature of 700 to 750° F for about 6 hours in an air circulating oven. Another method of removing epoxy coatings from small aras is by soaking the area in a suitable solvent such as Methyl Ethyl Ketone (MEK) or Xylene. ~~ Penguine_s February 5, 2006
For larger areas, such as in decorative collector's displays of coins or other objects embedded in clear epoxy resins, one will find MEK, Xylene and most organic solvents completely ineffective in dissolution of epoxy.
Air temperature cured epoxy can be "melted" by applying heat. Michael
Crosslinked epoxies are not soluble in any solvent, they only swell depending on the solvent used. Amine-cured epoxies may be destroyed by acetic or formic acid, pure or diluted by a suitable solvent (dichloromethane e.g.). I don't exspect vinegar to be suitable for removing epoxy mixtures, because epoxy resins are insoluble in water. It only may dissolve amine hardeners by forming a salt with the amines. On the other hand, acetone dissolves epoxy resins but often forms insoluble compounds with amines... I recommend alcohols (ethanol, isopropanol). --FK1954 (talk) 15:16, 14 January 2009 (UTC)
Anecdotal testimony has a solution of triethanolamine in CHCl3 and I think it was N-MePyrrolidone being used by military contractors during the 60's to dissolve the potting around Soviet chips for reverse engineering. Please do not do this at home -chlorinated solvents may attack metal. I believe in a pressure vessel but temperatures were not (too) extreme.71.31.152.220 (talk) 20:21, 23 August 2012 (UTC)"
There are two major gropes of coatings. One is thermoplastic coatings which you can dissolve thier film by choosing an appropriate solvent. The other grope is thermosetting coatings which you can't dissolve them, not by any solvent. Since, these coating were cured and a dense network was generated during the film formation reaction. So, the whole film is considered as a single molecule which cannot be dissolved. At the best condition you just can make the epoxy file a little soft or swollen by highly polar solvents.
Of accessible solvents, chloroform works for me, but it takes time (>overnight), and some high-quality temperature-cured special epoxies may not dissolve. UV-cured NOA61 and NOA81 dissolve in chloroform