So a while back, I was detailing parts and I took these pics of my headlight bucket that I was trying to repair. I saw patch kits online but found this product called HTS-2000 http://www.aluminumrepair.com/ and it is sort of pricy for a pack of rods, but I figured it's cheaper than buy a new bucket.
You have to build a trough out of steel metal to hold the molten aluminum. It's very tricky but once you practice a bit, you can figure it out. And the metal melts down hill so it took me a few tries to get it right. It was only a crack I thought I could fix but after the heat, it turned to mush. So I built the trough and clamped it down. Heat it very slow and take your time. It's not like plumbing / soldering copper pipes which is easier than this.
This angle worked best. Flow it on.
Took the casting / trough off.
Cleaned up and drilled the hole. Stronger than the original. So they say.