I have welded regular cast, but never aluminum cast. If you can find someone who has done it, go that route. If not, I'll give it a try, I'll just have to find the right kind of rod to use. Worse case scenario, you'll have some scrap aluminum.

If my people, who are called by my name, will humble themselves and pray and seek my face and turn from their wicked ways, then will I hear from heaven and will forgive their sin and will heal their land. 2 Chronicles 7:14