Shoretrooper undershirt

[Teepeethewelder]

Hey guys. As I am on a pretty tight budget, I am currently trying to do as much of my shoretrooper squad leader on my own as possible. Regarding the undershirt: I have located the correct material, and I have experience with sewing. However, I was curious about the ribbing on the undershirt. In pictures, the ribbing looks thick or puffy. My question is: can anybody tell me how many layers of fabric are typically sewn together to make the ribbing, and also whether or not there is another type of material (thin foam, etc) between the fabric to thicken the ribbing?