I fixed the cracks in my aluminum window frames by using my AC TIG welder. Wasn't hard to do and came out nice. Try finding a precision metal fabricating shop to get this kind of work done. The pricing of getting new bronze frames cast seems quite fair. I don't think getting them cast in aluminum will save you much money, and the bronze looks very nice on the boat. The way to go is to find someone whose is parting out a Triton and get the bronze frames from them.