As an alternative, why not avoid damage altogether...?
Hugh of Flambeau's axe (named Troll's Wife) in MoH p.51 has an effect that makes the wooden parts borderline indestructible. I'm sure I have seen similar examples on other items before, especially peoples talismans. There should be an equivalent Te effect..?
In that case it repairs itself twice a day, at sunrise and sunset. You'll need infinite uses, and even then duration is an issue, since permanent restoration is a ritual effect that requires Vis and can't be enchanted that easily.
I'll use the CrTe guideline at 15, which refers in the text to metals, but what if we transferred it to animal products or herbam products. Generally terram guidelines are the same but with 2 magnitudes added to up it from dirt to metal. So could we infer that the guidelines for repairing plant or animal products would be base 5?
Toa - I'd think that the repairing effect would be done in an instant like rego craft magic. Therefore upping the duration would create a continuous effect, i.e. it will keep repairing for the duration, if you do the sun/environmental trigger/2 uses a day, the item should keep repairing continuously.
In the 5th edition republish of the Covenant of Calebais there is a sword and armor or shield with a constant effect (Sun, 2 effect day, environmental trigger) that constantly repairs the item. I believe it was a base 15, R: Personal D: Sun T: Ind
Hugh of Flambeau uses a MuHe with a Terram requisite to make his wooden talisman staf unbreakable (Wood that Breaks no More).
Finally in Societates under the Flambeau spells there is a Mute spell Hardness of Adamantine that strengthens metal so that it both increases damae (which stacks also with Edge of the razor, but they still would need to Penetrate) and also increases the Soak of armor. Any combination of these can likely get what you need for physical force, fire or other things would probably still affect it.
"True", seamless constant effect is Sun duration, +3 linked trigger, +1 for 2 uses per day. But this is a construction, it's one single effect, not one that is actually recast twice per day (Callen had this quote from david chart confirming this, although I wasn't able to find the original post).
An effect with D: Conc, item maintains concentration, cast twice per day with an environmental trigger is similar in most aspects, but would fizzle at Sunrise/Sunset unless the user maintained concentration. This is actually cast twice per day.
I think that if you hit the armor with unraveling the fabric of animal, every bit of damage that has ever been done to the armor reappears until the item starts up again (which may be at the next sunrise sunset but I'll stay out of the continuous duration discussion for the moment). I've no books here but rather than stealing from the craft magic guidelines you could look at the guidelines for healing a wound on an animal (perhaps moderate) then adjust for how easy it is to create a living critter versus a treated animal product. In any case the some judgement is probably required. Just eyeballing it, level 9 seems low, I realize that range personal target individual makes things easy but this feels like level 14 or 19 to me.
An alternative to doing a direct magical patch up would be to actually use the craft magic rules and have the armor cannibalize some some extraneous straps and such to repair itself after every time that it is damaged.
What you've written in the description sounds a lot like an animal version of "Shadow of Springtimes Departed" from Magi of Hermes in the Ranulf chapter. This is a Cr(Mu)He spell creo to restore the materials innate ability to heal itself and muto to heal in the form of the enchanted object rather than the tree (or in the case of your armor cow) that it originally was.
A ReFo constant effect on the armor. When ever its damaged it would reassemble itself. Its a natural change too, even if one that would be difficult for most craftsmen. The materials used are whatever just broke off.
You run into weirdness with range then. If the missing piece falls off on to the ground you can't use range personal or touch, you can use range voice if the armor makes noise. I think that you want to use range special.
No, the blood is a cosmetic effect. The real effect is to "heal" the armor, and the armor is Animal, so an animal effect is what you need here, not an aquam one. Additionally, blood is Corpus or Animal, not aquam.
Ah, I see. The original post indicates that it is a thick liquid that is LIKE blood, not that it is blood. Which, as you've pointed out, changes what the requirement might be (if one were inclined to add a req to the effect).
Hmm... maybe not constant then, but with overlapping durations. Anyway, if a piece of the armour falls off it doesn't suddenly leave the spell. If you turn a rock into gold with a muto effect, breaking the gold into two doesn't mean one piece reverts to rock. Same thing here. If a piece gets knocked off its still under the effect of the spell. It could be reincorporated.
At least I think that's how an individual target works? I know group works like that. Leave the group and the spell effect remains.
This may be just me still learning the system, but...
If you broke off a piece of this armor, would that piece then try to "repair" itself by creating a whole new set of armor around it? It's still enchanted with the same magic, so what's to say that it wouldn't see itself as damaged and needing repairs?
What I wouldn't be so sure about is if a constant effect would continuously react to new damage. As it is Creo magic, the extended duration relates to how long the repair remains; it doesn't imply new repairs would be made throughout the day. After all, using a healing spell does not protect you from later wounds. I'd say twice each day, it'd patch itself up. Any damage taken until the next time the spell fires again isn't removed until the next healing wave.
I'd think there would also be a limit to how much damage it could heal. If it can just seal up slices and nicks, that's one thing - the equivalent of healing a Light Wound. If it can restore itself after being totally shredded by a pack of magic wolves, then that's something more potent by far. Also, if you are literally lopping pieces off, you are destroying the item and thus breaking the enchantment. You might be able to put the actual effect into a medallion or something else that could be considered a discrete item to avoid that problem but then you'd need Touch range.
that works, I was thinking about an effect that activated after the armor was damaged rather than one that was constantly active. I guess my aversion to items that could conceivably warp themselves over time (from a player perspective, I love them as a story guide) made me immediately think about the reactive option instead of the always active option.
It seems to me that, for these, unless your SG wants to pick on you, this is the occasion to negotiate all kind of special SFX that'd make your item cooler and more fantastical, such as an armor that gets glowing verditius runes, or a book that sprouts leaves.