Can the reinforce spell be used on an armor jacket to increase its armor rating?

Not in my game!

Although one could just rule that “It’s magic� i would rule that reinforce does just that – it makes the material more rigid and harder as it is a manipulation spell that alters the material.

End result would be that the new armour rating would count against your body and possible give dicepool reduction.

The same would apply to vehicles as their handling would suffer (but not gunnery, sensor operations and the like.

So, with those tiny restrictions I would allow it.

Thanks, someone in a game I just started wanted to use it and I thought I'd get a consensus. I like the idea you give about using the new armor rating against body. Makes Armor worth the extra drain without making reinforce useless.

yes, but it also makes the material less flexible. Think wearing boards as armor.