Making Spoilers

How do you guys make your own spoilers? I have this clear plexi plastic stuff thats perfect for it, but I'm stumped as in how to do it....any ideas?

i use .05 plastic sheets for spoilers apply little heat and they bend like magic.

okay well i've tried i just dont know "how" they are suposed to look or what else i should do.........ack do you have pics of spoilers uve made?

what i find useful is to find something that resembles the curvature of the bends and use those as a starting point. i found it easiest to cut the areas that i desire from the host part and add plastic sheet to my taste or per any references. one thing i've learned is not to use putty unless it is for pinholes. my experience is that putties tend not to sand as evenly as plastics and would result in some undesirable wavy areas.