Welding cast iron is pretty iffy- you have to pre-heat it and use cast iron rod. It will cost a lot more than $30- worth doing to try to salvage an engine block, but not a griddle.

Slow set JB Weld would work but not sure if it would present a toxic condition contaminating the food or not. Might be worth the trouble to contact JB Weld, I'm sure they have a contact email/phone line at their web site.

Let us know what they say if you do contact them.

I've had success brazing cast iron with an
oxy-acetylene torch and brass rod.
Make sure the area to be welded is ground
down super clean.