I believe just this week I got a stern warning from my teach about people wanting their aluminum boats welded. His advice was this, in a nutshell...... "RUN", lol. Unless you REALLY like them, like they're you're dad, brother or best friend, and it's not about the money.
It isn't ever going to be clean, it won't be a small hole like they say, it's most likely going to have paint on the inside, they're going to want it in a hurry to go fishing now, and they're not going to want to pay you for all the hassle. (and they probably won't leave you alone while you're doing it either)
So I really chuckled at this post, because I just heard this no more than a day or two ago :)
FWIW
Jenn