On Fri, 09 Oct 2020 20:52:26 +0100, Brian Gaff \(Sofa\) wrote:

I don't think this is a new idea though, but the equipment may be. When
back in the 70s we had this house rewired they cut the edges round using
some kind of hammer tool and then just gunged out the middle. That was a
technical term used by the elecctrician.. grin.
Brian


I've done it quite successfully by hand with a cold chisel and hammer.