The mountain bike that I use for commuting is broken and I don't know if it's terminal or not. It's an aluminum frame and the right side chain stay, beside the chain, is cracked loose from the bottom bracket housing at the joint. Can that be repaired / should it be repaired, or is it finished?
It's a decent quality bike, but older and I've gotten a lot of mileage out of it.
If it were steel, or even titanium, I'd say a definite yes. Aluminum? Not so much. I've heard of people doing a kind of composite wrap over aluminum, which might do the trick, but aluminum frames are kind of throw-away items (unfortunately).
Time for new one. And don't ride it anymore either.
You can find some cheap frames out there. I bought a frame off ebay that is probably off the same line as the low end Raleigh MTB's with some other sticker set on it. Got it new for $10 plus shipping. I've been using it as my baby trailer puller. It's actually much nicer then what you'd expect for a $10 frame.
I've purchased a couple frames from these guys over the years for beater bikes. They usually have a couple you could go with.