I picked up this very cool 96-97 GT rage from Craigslist with the intention of restoration- a few rusty pinch bolts, spider eggs in the brake hoods, grinding bearings and pitted races, and all the good stuff that comes to a bike living outside for 5 years.
I was excited to get my first aluminum frame for the project as I knew it wouldn't be rusted like steel would have. (It spent a lot of time in the rain.) It wasn't for another day until I found hairline cracks forming under the seat post clamp and around the GT rear stamp. I suspect the clamp was over tightened at one point, but it was very normal when I got to it and the little slit cut into the back of the tube isn't squished or malformed which I've seen happen on steel frames that were over tightened.
How long will the frame actually last? It's a GT so it's got the triple triangle so I'm not worried about my seat stays coming loose or my seat post falling into the tube. Should I be? I know fatigue cracks in some places means it's time to trash the frame, but I'm not a pro racer and I ride pretty lightly. I'm interested in other people's experiences with aging aluminim and possibly hearing thoughts aside from putting it on the curb for trash day.
I can feel the cracks with my fingernail but they're too small to actually fit my nail inside.
I've read 7005 aluminim cannot be repaired since it requires heat treatment. I love this bike because I love 90s and GT (and its so hard to find tall frames that aren't 70s gas pipe builds) but I'm not sure it's worth being a money pit. Are there other repair options? Does drilling cracks actually work? Can I permanently install the seat tube?