[yorkie_chris]

Yes because they are subject to fatigue stress every time you let your missus pack and there is 300weight of crap bouncing around every time you hit a bump.
BUT it depends entirely on which joint in what sort of structure.

I reckon something from stainless tube would be better, or even mild steel powdercoated. You could do reasonable job with a £50 buzzbox welder if you went for mild.