Hi there,
I am thinking of getting some Coroplast (called Correx in the UK) for an undertray. Instead of buying the pricey 4mm stuff from a signmaker I think I'm going to use 2 layers of 2mm black material like builders put down instead of ply these days.
It's around £4 - £5 a sheet (2.4m by 1.2m) from a local builder's merchant.
Trademate by Travis Perkins
(No association - other builder's merchants are available who may stock correx sheets)
I had to sign up for a cash account card (free) to buy it, but no fuss otherwise. I recon a whole undertray can be made for £20ish.
I will post a separate thread of the undertray / belly pan build when the time comes.