Need help with silicone for isolator on 5a reproducer.

[VanEpsFan1914]

Hey Martin, try using a razor blade or an X-Acto hobby knife to get the halves separated. Just run it round the edge of the thing.

I know this is about that fancy HMV gramophone, right? Nice score!

[Inigo]

In a couple of cases I had, I solved it by carefully cutting the front ring, to free the accumulated stress. This is because the back is put metal and has swelled a bit with the years. Once I cut the front ring, I put a piece of paper between the cut area and the back, reassembled it, and refilled the cut with two component metallic epoxy. The paper strip under the cut is to avoid the epoxy from adhering to the backplate.
Once hardened, you have a solid front ring, slightly larger in diameter, but it fits the soundbox backplate.
It's also beneficial to polish the backplate, especially in the border rim that fits into the front ring.
Because of the subtle enlargement, the soundbox outer protection will not fit so well with its for screws onto the front ring, but this can be forced somehow when reassembling.