Sorry if this is a repost, I couldn't find anything on it after searching
After leveling my engineering, I was messing around with a Goblin Beam Welder and found that if you have yourself targeted when using it on a mechanical creature, you heal yourself for the 7200 instead. Normally this situation doesn't happen too often, but if you drop a Target Dummy you end up with a small heal you can use anywhere. You can also heal other people by having them targeted.
Although not a huge heal, this trick could come in handy for lower downtime on leveling or an extra heal in Battlegrounds (Especially if you learn it by 65).