I've used acrylic sheeting to make mine. It should insulate better than any type of metal- check out the site in my sig for pics.

David

Mondeo ST24 Information Site

yr 2000 silver Mondeo ST24 V6 MTX
mods: Custom alloy air intake using K&N RC-3250 air filter; Koni Sports shocks; rear 20mm Selbys sway bar; THF; EBC Greenstuff front pads, custom exhaust.