A way to make a strong, light, insulated door for a custom application

How to laminate a quick and dirty R-3 stressed skin insulated panel door.

I needed a pair of carriage doors for a garage. They needed to be strong enough to create an airtight seal, be insulated, lightweight, inexpensive.

BTW I couldn't find any custom manufacturer of carriage doors anywhere at any price.
I also asked for expert advice just in case this had been done before:
http://www.greenbuildingadvisor.com/community/forum/green-building-techniques/28281/air-tight-garage-door

Видео A way to make a strong, light, insulated door for a custom application канала Kevin Dickson