I am making an urn to hold the cremains (ashes) of a client's husband. Shape and size has been determined as well as the glaze. Client wants the ashes to be "hermetically" sealed. As you know, when glazing, the two pieces would be fired not touching and probably having rims of both the urn and the top with no glaze where they would fit together
Question: If I hand dipped each piece as well as the inside rim of the urn but not where the ashes would rest, then poured the ashes in the urn, placed the two pieces together (remember, no resist being used), and fired it so the urn itself and the top would fuse together into one - Would the whole thing blow up at some point because of built up pressure during firing? If it didn't blow up at that point, could the vessel have a higher than normal pressure when it cools down and therefore be more prone to fracture or blow up later? Lastly, after researching the cremation process I discovered the temperature used to render a human body to ashes is about 1650 F. I use cone 6 when firing, about 2355 F. What would happen to the ashes? Remain the same, coalesce into a lump, melt?
Any past experiences would be appreciated,