thanks for your help. I will check it today. I should probly get the seems welded then.

 

when looking for leaks, use a short length of garden hose and put one end to your ear (but not on your ear). then run it up and down your pipe to see when the leak is. also, there should be carbon streaks on the pipes where there are leaks. where it starts is closest to the leak. you could also try removing the disc from a stethoscope and using that. good luck.