I'm not sure, but don't ask Brodie.
Funnily enough, the 4047 (AlSi12) filler didn't work at all. It instantly crystalized and even if I did get it to work, well just look at the last picture. 5356 (AlMg5) was used and wetted out nicely and uniformly.
Not really working that much with alloy welding, but isnt most japanese castings magnesium alloyed aluminium?