you can use hide glue, but it's water soluable. some use super glue. that's pretty much what most commercial fletching glues are. Or, you can just tie the feathers tight at the back, leave a little extra quill sticking out, tie the front where you want it, the use the extra quill to pull the feather tight to the shaft. secure what ever you use to tie it with (sinew, dental floss, thread, or whatever) with a few drops of glue and it will be stronger.