i was still leading some things in the body shop i work at but not every one was using it .when tined good the bond is 100% but for some guy that never used lead. a roof would not be the place to learn .i started to play with leading back over 30 years ago .i was leading things before i had a driver license. but i not a pro with it i can get 80% of the stick were it need s to be well now maybe alot less abit rusty .but the added heat can warp any thing you use it on. you have to know if it can take the heat like i said i did the nose of my chevy hood i knew the flex the filler may not hold well there. i knew i could not lead the mild part of the hood the heat would of turn it in to junk