RE: Looking for a Source for Coroplast Sheets
I don't know about 6mm as i have not seen or used it, but your local sign shop may be able to provide you with 2 mm and 4mm which is more commonly used for SPAD aircraft. Another cheap (FREE) source of 4mm is the political signs strewn about our landscape before most every election. I ask the supporting body of the candidate before removing them after the election, and they usually welcome your help in cleaning up the trash . Sometimes there is a common collection point (like our civic center) that helps in the recycling of the signs. You can sometimes pick the color(s) of your choice. Good luck.