I've been welding schedule80 pipe in preparation for a 2" XXS pipe test. Regardless of how many roots I run I continue to have a problem with tying-in to my tacks. Each tie-in has what resembles a 'fish-eye' or a dimple that is pretty obvious when reviewing the finished root. I have been able to tie-in a few times with no problems with the fish-eye but even then I am unsure as to how I achieved that. Does anyone have advice for tying into a tack with the root looking seamless?