Sterling Silver ring won't gold plate?

Hi! I have been gold plating jewellery myself for a few months now and I recently bought a sterling silver ring and tried to gold plate it but it didn't react or change colour at all. Any ideas why this could be? I had something else in the gold plate solution at the same time and it coated perfectly but the ring didn't change.

Could the ring potentially have some sort of e-coating on it that is preventing it from being plated? I notice the jewellery company I bought it from have in their info that they plate their own jewellery then finish with a clear e-coating to protect it so if it is e-coated with a clear layer does that mean it won't be able to be gold plated?

Might be a stupid question but I've plated 925 sterling silver many times and this hasn't happened so not sure why. Any help would be appreciated!

I think you may have answered your question, my guess would be yes it is coated with something, most likely need to remove with a abrasive or pickle may remove it.

E-coating for silver jewellery. ... Silver plated items are generally coated with clear polyurethane electrophoretic lacquer which gives it very good tarnish resistance. Theoretically silver plating does qualify to be called e-coating but in actual practice e-coat refers to electrophoretic coating.

If you have more of these to do in the future, get some paint stripper to remove it. It's also possible that if you already have a paint solvent, or acetone, that would work. Dennis.