I'm new to this form. I've use this stuff called Aladdin 3in1 rod, you use it on aluminum to fill holes,cracks or what ever, it really works good. you need map gas not propane and a stainless steel wire brush. dermal a grove in the crack and then use the stainless steel brush and clean it really well . heat it up, and use the rod and touch the metal and melt the rod in to the aluminum. don't heat the rod under the flame you what to try to melt it in as if you're soldering it. youtube has lots of video on it . you can find it at a welding supply store, i went to air gas it cost around 25.00 if i remember . hope this helps.