(OOC):
Some questions to take stock of abilities and such:
- Is it just metal armor or armor in general that conflicts with spellcasting?
- Can the difficulty with mechanical items be partially worked around by enchanting a specific component (such as a spring or wheel) and than adding it in afterwards?
- Are temporary enchantments (lasting a few hours to a day) reasonably doable if you have the time to prepare them?
1. Armor comes in 3/4 types:
-Cloth (ie. Not armor), which provides no real bonus to DR while at the same time doesn't hinder spellcasting or anything else that might take a negative modifier from armor.
-Light (leather, hide, poorly made chain mail, etc.), which provides a small bonus to DR but also slightly hinders spellcasting as well as providing a slight penalty to some checks.
-Medium (chain mail, scale male, half plate, etc.), which provides a moderate bonus to DR but hinders spellcasting and provides a moderate penalty to some checks.
-Heavy (full plate and the like), which provides a rather decent bonus to DR but several hinders spellcasting and provides a rather hefty penalty to certain checks.
Light, Medium, and Heavy armor also increase the base backfire chance of a spell, depending on what type of armor it is. Generally light raises it 5%, medium 10%, and heavy 15%. For each round spent casting a spell or performing a ritual, the backfire chance also gradually goes up- meaning that the lengthier spells are inherently more dangerous.
Gnomes get a nice little bonus to item creation rolls as a racial talent, but this is balanced out by another racial talent which causes the backfire chance of spells to rise at a more rapid pace.
2. The current rules as written for engineering states that any attempt to upgrade or modify an item mechanically will disrupt the enchanting placed on any or all parts of the item, with a chance to backfire for each spell used in the enchantment. On a flavor-scale, this is because the way magic works is that it encompasses the whole of the effected thing rather than just parts. Or at least, from a flavor standpoint, that's how
enchanting works. From a mechanical stand-point, it's to prevent a 3rd level knowledge character from making some amazing magical rifle that can, like, fire sunlight or something (though that would be pretty cool!). However, you just gave me an idea for a talent to beef up the Engineering/Magic tree with...so the answer is yes, but you need to be particularly skilled in both the art of engineering and the art of enchanting.
3. These enchantments would be less enchantments, and instead regular spells that provide buffs. So yes. I should point out that while wizards certainly
can cast buff spells, you'd have access to more spells like 3.5 D&D's "Bull's Strength" as one of the Devotion path's spell casters (Priest, Shaman, Witch Doctor, or Druid). Wizards get nifty utility stuff, instead. That doesn't mean your plans to be able to enchant and buff yourself and allies are for naught, though, you'll have your fair share of buffs and pseudo-enchantments.