have you tried quite steel?My dad used that stuff to put a motorcyle block back together.It held in back and forth traffic for 2 years and after that he sold it and it still run.I've repaired exaust leaks with it.Good stuff I think its 3 bucks at any autozone.heres a link to thier website in case you don't have them in oz.
AutoZone.com - Get in the Zone!