I'm not sure you need to have any kind of 'mold' from foam.. I mean, it looks like you have 2 'flat' surfaces (they are the long ones that are flat on the ground and have the curves in them).. if you cut some MDF that's flat on the one side and has the curves to the other side (you would have 2, one for each 'face'), you should just be able to pull the glass tight over that curve while building it up.. I would think a staple or two to hold it tight while the first layer dried would be fine.. and that helps give you maximum volume.. *shrug*
That's just what it looks like to me...
(1) Alpine CDA 7892 HU ($214)
(2) 12" Pioneer Premier 1241DVCs in sealed MDF box (gonna glass them eventually) ($69 each)
->removing.. ->(2) 10" Pioneer Premier 1041DVC's in sealed MDF box (gonna glass them eventually) ($59 each)
(2) Lanzar Vibe248 1200 watt 2 chnl amps ($119 each)
It's bump'n GOOD!
You can lead a horse to water but you can't make a moron understand...