There is a tape made by 3M , it is some 1/2" wide has a sticky back & has the very jagged edge you are looking for. It is used by women to put in their hair when doing a perm I believe . It is a pink color , comes in a plastic roller like scotch tape & is some $4 a roll .3-4 rolls will do a fair size model . I put it on & then put some dope over before painting . I got it in the drug store , C.W.S. I think . I have used it for years , good stuff .