I wouldnt say you cant. But it really depends on a lot of things.
quality of the FC wire being one. for example Using a good wire like hobart fabshield 21b will usually get you better results than generic FC self shielded wire or even lincoln nr211
JD uses a lot of .035" dual shield in the field but it requires shielding gas ..usually 75/25 ar/co2.
its less portable but worth it to him to carry the cylinder for the bit of extra heat and quality of welds.
I would definitely do some simple fillet weld tee joint break tests first.
hope this helps,