So, according to AoN you can use an Acid Flask as a Focus component when casting acid splash, for an additional +1 damage and liquids ice the same way but for Ray of frost. My question is what are the mechanics of doing so?
Normally focus components are drawn and replaced as a part of casting a spell, but I couldn't draw and store an Acid so ask as a part of a standard action normally. So which set of rules apply? The normal move to draw which provokes, and move to store which procokes. Or do the spellcasting rules take precedence.
Also, do you have to hold the flask or can it just be exposed in your person and you lay your hand on it or something like that?
Because I needed to search for the phrase "alchemical reagents" that was my problem.
As far as I can tell, you would treat the focus or material component part of it much like you would normal foci or material components. You would need a free hand to manipulate it while casting the spell. Normally you can manipulate the components in your pouch as part of the casting with your free hand. Foci, like divine foci, are often worn as a necklace or something similar. I would imagine if you have the flask available where you can freely manipulate it (like a bandoleer) you could do so without needing to spend an additional action.
If you had the components or foci somewhere not easily accessible, like a backpack or material components not held in a component pouch (or if that pouch were someplace inaccessible) then I would rule you would require additional actions (which would provoke) to cast it.
It uses the same action as drawing material components for other spells- as in, its part of the action of casting a spell.
It’s reasonable to require that material be easily accessible like normal for a spell component pouch- it could be in a pocket on the inside of a cloak but it can’t be inside a backpack or handy haversack, or otherwise stowed with the purpose of hiding it from others.