Basics of Fusion: Anything beyond Iron costs way too much Energy to be created. And Iron itself doesn't generate Energy, only the Atoms below Iron do. I don't know if your Recipes follow that Rule, but they should if you didn't do that.
You could create heavier atoms by a so called r-process, a thermonuclear explosion would be enough to created very heavy elements like einsteinium and fermium. You don´t need much stuff to create a thermonuclear bomb, but controlling the explosion could be a bit... difficult.