If your aluminum rudder quadrant shatters, you might be tempted to simply have the pieces welded back together! This will work as a temporary solution, but it will never be as strong as the original.
Our rudder quadrant shattered, and we did just that! We paid a welder to "glue" it back together so we could keep sailing along. We knew we would need to replace it with a new one, but the further we sailed, the less we thought about replacing the quadrant.
Several months passed by, and securing a replacement went from a top priority to another item on the list should we happen to stumble upon it at a consignment shop.
Then we had a serious mishap occur and the rudder quadrant shattered again!
Looking at the cross section of the break, you can see that the welded aluminum has a different crystaline structure when compared to the cast portion. You can also see the depth of penetration of the weld. This means that only the outside of the quadrant was re-welded, and the inside merely sits approximated but not welded.
I don't weld, so I can't really judge on the quality of this weld, but I can state that this welder also fabricates stainless steel and aluminum towers and railings for boats. The quality of his other jobs gave me the confidence that this repair would be as best as he could do it.