Here is a front head for one of the motors that we are doing in this batch. It is a really nice head, all five tabs have never been broken, the insert doesn't leak, and the exhaust port has never been cracked. However there are some fins missing. uh oh.
Here are the fins that I made up. When I first started to do fin repair, I would make each one fit perfectly. This did not work well all of the time.
Here you can see that the new fins are a little taller and longer than the intact original fins. I do this on purpose, so that after a little bit of grinding everything lines up and be parallel and perpendicular.