MMC insulate the inner wings from the outer using a leather gasket - this is my sport in build last september
I find that amazing that leather, which is porous is used as a separating gasket. Surly high tec neoprene would be better, even old malthoid roofing salvaged from the chicken shed would do.
BTW that is an amazing picture, the gauge looks like it would fit the underground rail system at a pinch?
