Elemental Magic: Transforming Air

Changing air to metal is different than changing it to a finished project. From A&A pg 25:

This could be another way to skin the cat as a CrTe would create a perfect suit of armor. Could MuAu(Te) do the same? I would think it would need a lot of finesse if allowed. I would say not but you could turn a volume of fog/wind/rain into a big block of metal.

You can turn a person's mind into a bird via Muto. It has the category of bird, but it still has an essential nature of a human mind, which is why its body could be attacked with Mentem.

You can turn air into stone stairs, stone bridges, etc. Stairs, bridges, etc. are finished products, not merely blocks of stone. Complex shapes require higher Finesse rolls.

Why can air not become armor? It has the category of armor and the essential nature of air, so it could be destroyed via direct PeAu, while normal armor could not be, for example. Yes, armor can be pretty complex so there would probably be a somewhat significant Finesse roll required. Perhaps extra magnitudes for complexity?

A MuAu(Te) to turn the Air unto metal with a Re prereq to manipulate the metal via craft magic. Making a mail shirt would be average work that normally takes a month (12+3) for a finesse roll of 15

So my guess would be base 5 R: Touch, D: Con, T: Part Te and Re requ MuAu(ReTe)30 with a finesse roll of 15+
vs
base 5 R:Voice D: con, T ind CrTe 20

It would work and would be another way to skin a cat.

I don't see the need for the Rego requisite. Magnitudes for complexity, sure. But other spells don't seem to use a Rego requisite that way.

Which other spells create something without creo into a finished product?

Well, there is the very spell used in the OP to design these: Conjure from the Mist. And there are more, like Remake the Tailor's Craft. We're looking for Muto spells, of course, since you want non-Creo and the point is not needing Rego. I don't have time to search lots of books, though.

I see turning simple and undifferentiated air into simple and undifferentiated stone as relatively easy; into roughly worked stone a bit harder, and into carved statues harder yet. Air into worked metal armor is quite a few steps.

Switching one form to another should include a degree of flexibility in the final shape, as this is the declared purpose of the spell. As long as the spell is creating a specific object or thing. Air to a plant is fine and declaring the type and shape of the plant is reasonable at base.
Then modifying for complexity in shape seems appropriate.
I see the complexity as quasi- geometric shapes (+0 mags) like lines, cubes, boxes, or walls. Exploiting a feature of the new material should be free too - like using a plant to create a natural shelter.
The allowing sub-shapes in the main shape (1) like windows, basic stairs, spikes. Then almost any other ordinary detail (2). Then finally very ornate details as (3) like artwork, .
Having the additional mags should allow forgiveness in the Finesse church but not remove a basic "fit for purpose" check.
So a basic sword is +1, and a full suit of armour might be +2.
Then add mags for flexibility in choice of form when casting. Like making a dagger, knife, and sword which is serviceable chosen at cast time.

I remember that when Silvery Scales of the Knight was brought to 5th Ed, it was pointed out that the armour had to be made and then put on. That the finesse rolls to have it appear on you were way too high. The SSofK description in HoH:TL p37 mentions putting it on - which to me, means that it appears in front of you, not on you.

There was a discussion on the forum a while back which I think applies to this project.

https://forum.atlas-games.com/t/magic-tools-in-the-laboratory/8469/1

Creating armour with Creo doesn't need much in the way of finesse. Using muto to change air into armour would require a good finesse or you would just end up with pieces of oddly shaped metal.

I think the discussion about if air itself, without air phenomena around, is still a valid target is missing a Criamon magi, who probably would start talking about Empedocles:

I sounds to me that Empedocles developed among others the Art of Auram, and having proved that air is something, he probably made sure this art could affect it even when there aren't mists or lightnings around.