I've been trying to fully understand how Magic Item Creation works, specifically an item with multiple abilities, but there's still one thing that I don't understand: How do you determine that final Caster Level of the item (and thus the DC of the spellcaster check)?
This is what I've gathered so from the rules and online forums:
Creating an item requires 8 hours of work per 1,000 gp in the item's base price (or fraction thereof), with a minimum of at least 8 hours.
With base price being defined as how much the item is priced in the store, and not the discounted cost for crafting the item.
For example, Ring of Invisibility is priced at 20,000 gp, and the cost to craft it is 10,000 gp. A player wishing to craft the ring must spend 10,000 gp and 20 days/160 hours (since the base price is 20,000 gp) to craft the ring.
The DC to create a magic item is 5 + the caster level for the item
Items you can buy from the store usually have a CL listed.
For example, the Ring of Invisibility has a CL 3rd, so a player would need to take a DC 8 spellcaster check to successfully craft the item.
From what I can gather, the cost to craft a magical item with multiple abilities costs the full price for the most expensive bonus, then 1.5 times the price of each additional bonus. See http://paizo.com/threads/rzs2nge1?Question-about-creating-Ring-with-multiple
This goes along with adding additional abilities to an item
If the item is one that occupies a specific place on a character's body, the cost of adding any additional ability to that item increases by 50%. For example, if a character adds the power to confer invisibility to her ring of protection 2, the cost of adding this ability is the same as for creating a ring of invisibility multiplied by 1.5.
The base price to add Magic Aura as a continuos effect is
Use-activated or continuous = Spell level x caster level x 2,000 gp
With a note that
If a continuous item has an effect based on a spell with a duration measured in rounds, multiply the cost by 4. If the duration of the spell is 1 minute/level, multiply the cost by 2, and if the duration is 10 minutes/level, multiply the cost by 1.5. If the spell has a 24-hour duration or greater, divide the cost in half.
Since Magic Aura's duration is 1 day/level, the final price would be 1,000 gp (1 [spell level] x 1 [caster level] x 2000 gp / 2)
Which makes the final base price of the item 21,500 gp (20,000 gp + 1,000 gp * 1.5).
This means that the cost to craft this item would be 10,750 gp and 22 days.
Does adding the Magic Aura effect to the Ring of Invisibility increase the final Caster Level of the ring, and thus the DC spellcaster check? If so, by how much? Just 1 since I used Caster Level 1 to add the effect, making the ring a CL 4th with a DC 9 spellcaster check?
When you upgrade a magical item or add additional abilities to an existing magical item, do you take a DC spellcaster check at the end of the crafting time? The rules do not state this outright and I've not been able to find an answer.
- If you do, do you use the CL of the new ability for the check? With the example for adding Invisibility to a ring of protection, would the DC of the spellcaster check be that of the CL of the ring of Invisibility (3rd), or something else?
Does the CL of the item increase when upgrading an item? Bracers of Armor has a CL 7th regardless of the strength of the enchantment bonus. Would upgrading the bonus from +1 to +3, or +1 to +5, still use a DC 12 spellcaster check?