Is this normal wear and tear or did I do something to cause this? I
will have to buy a new mandrel; I do not want to crack the new one.
You can repair it if you want to. You do need a large acetylene
torch for that. Sprinkle borax on the cracks, be generous. Warm
copper wire and deep in borax as well. Borax should adhere to the
wire. Braze cracks using copper wire as filler. Copper should reach
liquid phase. It may require some filling afterwards, but it will be
better than new.