[fhhhstix]

I use rubber roofing it comes in different thickness. I am lucky and have a good friend that works for his brother that owns a large roofing company so I went and ask him for some and he cut me off a 4ft x 4ft piece the same thickness as the tamiya flaps at no charge. So I would suggest stopping by a local roofing company with a tamiya flap and ask them if they have any scraps that thick and tell them what it is for and I would bet they will be more than happy to get you a piece.