I'm having a small amount of luck wet mounting my paper to alu-panel (composite board made from two aluminium sheets sandwiching some kind of plastic)

I mount them to help with registration.

I soak the paper, let it drip a while, spray the back with gum arabic, then lay it on the board. I tape the edges with watercolour gum tape.

Stays put for about 3 or so layers.

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