Jon Elson wrote:

Without a heat
treat oven, is every weld repair going to end up producing another crack?

Did you drill the end of the crack? You should do this!
carefuly check that you drilled out the end of the crack (oil and chalk)
or it will certainly crack again.
Preheating by any means will reduce inner tension.


HTH,
Nick
--
Motormodelle / Engine Models
http://www.motor-manufaktur.de