@Ifusaso I wasn't trying to undermine that first position but trying to give equal attention to both readings. What fallacy is evinced by the first point?

Also there are a couple of weapons with innate magical effects or which you would probably say have default special materials e.g. the Null Blade and, though not a melee weapon, the Id Rifle, both from the technology guide. Presumably you can pick those since even e.g. a default Null Blade has said properties and Null Blade is an entry on the weapon list in an equipment section and not, e.g., a magic item section.

@Pleasestopbeingevil Yeah, weapon size is a definite oversight in the spell description, and I don't really know what to do about it. I can say that I'm not sure there is a default weapon size like there is a default weapon material: "Every weapon has a size category. This designation indicates the size of the creature for which the weapon was designed." While the table only mentions Small and Medium, the narrative doesn't seem to adhere to, for instance, all weapons being designed for Medium or Small creatures by default.

@Pleasestopbeingevil We might have to disagree on the null blade; while it's on a weapons list, it's a magic weapon no matter if it's powered or unpowered—the null blade is a +1 construct–bane bastard sword and the Technology Guide lists it among the hybrid "[i]tems with both magical and technological components" (17). It even has a magical aura. And I don't how to speculate about the id rifle as it's a ranged weapon: it might not come with ammo in the same way that a GM that allows a shadow weapon bow (as an improvised weapon maybe?) likely wouldn't have such a bow come with arrows.

@HeyICanChan You can't get a ranged weapon with shadow weapon, the point is it's made of skymetal in the default description (unhelpfully doesn't specify which, but I think Adamantine is said to be the default there somewhere). But if the (implied) restriction to only mundane, non-modded, ?iron or wood? weapons is not based off of those being (most of) the default versions for weapons in the weapon tables, then there isn't a problem; you just couldn't pick a weapon that was skymetal by default or if you do it's iron instead or something.

@Pleasestopbeingevil So far as I can tell, the id rifle is unique in being mundane yet "made of burnished skymetal." But, while adamantine is the "most commonly known skymetal" there's no other mention in the Guide of which skymetal is the id rifle's burnished skymetal. I suspect that, absent such details, an id rifle's skymetal construction is just a nonmechanical detail and that the id rifle's actual hardness and hp remain the same as for any other metal two-handed ranged weapon. That would make it would be up to the GM if that still counted as a "special" material.

@Pleasestopbeingevil (Looking a little deeper, Tech Guide says, "Unless otherwise noted, skymetal has the same hardness and hit points as steel" (56). So an id rifle, as it isn't otherwise noted, would be made out of that skymetal.)

I think I figured it out! I also clicked move to chat before post so now I have to retype this comment. Basically Special Materials are not just less common they're actually different for you, which is why a bone club and a +1 club seem like the same thing here, because for you 'bone' and '+1' are both additions to club, rather than something that has to be there

That seems textually supported by the materialless weapon hp and hardness table stuff, but I've always thought those were just helpful references combining object size with 'probably made of iron' v.s. 'probably made of wood'

Hence the confusion on account of, for me, material not being something added to a weapon but something weapons always have to have, just it's usually iron, steel, or wood.

But I think the idea that it's not actually iron steel or wood, like, in the same way as Special Materials have properties, but instead only sometimes an actual thing and usually just a lack of material properties in the same way a weapon usually lacks magic, modifications, or other optional additional subsystems

*makes sense

That also means that the weird difference between the Wizard and Battle Host bonded object isn't a thing, because the Wizard class feature didn't need to say 'not made of special materials', which is relevant for a build I have. Woops.

For what it's worth, I believe the general rule of thumb is that "if a spell doesn't say that it allows you to Do The Thing, then it doesn't give you any special ability to Do The Thing". In this instance, it doesn't say that you're allowed to choose the material the weapon is made of, so you use the default material, which is steel and/or normal wood in most cases.

@Pleasestopbeingevil Curse chat for not alerting me to these comments! It sounds like you're agreeing with the answer's second reading? If so, I'm glad to've helped.