Making pattern for mould

[Mr Gazza]

The under seat tray is already a great material to take a mould off. It'll be polypropylene based which releases really well.
I've recently taken a mould off a number plate mount and it pops off a treat with just release wax.

Easy composites do a range of excellent mould making products. https://www.easycomposites.co.uk/mould-making

There's polypropylene sheet in there which is great for flat surfaces and single plane curves.
A hot glue gun is handy for sticking it together, especially if you're trying to extend a mould from something you want to keep afterwards, as it just peels off.

There's sheet wax, plasticine, soft wax for filleting and all sorts.

I favour using rigid foams, preferably the yellow stuff in the middle of Cellotex, with the ally foil peeled off. I sculpt this and then sheath it with a thin layer of 18gm woven glass cloth in resin. (epoxy or poly.) I've also used water based polyurethane varnish which works well if you're painting the object, but no good for a mould.
I'll then coat the sheathed foam with gel or epoxy and rub it back to a dead smooth finish for polishing and waxing for release. The woven rovings and resin sheathing are great to unify the surface if you've used several different porous materials like foam, MDF and ply for instance, or just stick to polypropylene, plasticine and wax which always release.

I think East Coast Plastics also sell the same products. https://www.ecfibreglasssupplies.co....Khsx8-BseLL2Mw