1970 emissions fuel tank
 

I bought this tank and was removing the old hoses and the vent tube broke at the solder joint I think. Is this an easy repair or did I ruin the tank? I put it back in the hole and it's tight doesn't move. I didn't realize it's so fragile.

I would think a radiator repair shop could fix you right up, provided there's one still around.

If its just a normal solder joint you should be able to re-sweat the solder in the joint like home water pipes using MAP gas. I had a leaky trans cooler fitting on a factory radiator I did that to and it sealed up fine and was leak free for 15+ years until I sold the car still leak free.

Soldering or brazing it back on should be pretty easy.