What are the effects of the elements on 3D printed objects made with "infused" PLA I came across a new Steel infused PLA from Colorfabb. On the store page someone had asked, what happens if it was exposed to water, would it rust. I am actually, not sure what would happen. I am interested what the effects of leaving in the elements a 3D printed object made of the 2 most common type of fused materials. 


Wood Infill
Metal Infill (not stainless steel)


Would it be preserved by the PLA coating it, or would, over time, rust and dissolve? Would the wood last forever, or will the print get discolored and become mulch?
If you use filaments filled with metal particles, some particles will be exposed to the environment. Depending on the corrosion resistance of those metals, yes the environmental conditions will weather the print object. So if it contains iron (and does not contain elements that prevent oxidation like used in stainless steel) and it is subjected to water and oxides, the print will rust. 

This is e.g. also valid for copper filled filament, which you can polish to get a gold shine surface (removing the copper oxides), or bronze filled filament, that if correctly subjected to weathering environments, will give the looks of a very old statue. In both cases this implies that the metal particles have undergone a(n) (de-)oxidation process.