A decapsulation apparatus has an etch plate, an off-center etch head having an opening, a cover sealing to the etch plate forming an etching chamber, a gasket surrounding the opening, a ram sealed through the cover, a pressure-controlled source of Nitrogen or inert gas continuously purging the etching chamber at a low gas pressure, a f toggle mechanism mounted to a metal plate t, an etchant supply subsystem comprising sources of etchant solutions, an etchant solution pump, supply passages and controls to select etchants and etchant ratios, and a heat exchanger heating or cooling the etchant solution, etchant waste passages f conducting used etchant away. Etchants are mixed in the passages to the reaction region, and turbulence in the reaction region is promoted by impinging etchant solution on the encapsulated device.