I playing two characters in an adventure path and one of them it's the brawler that I have been asking about and the other is an alchemist. They are both 6th level now. My question is can an alchemist user their formula to create magic items other than potions? I know that they don't actually cast spells so I didn't know if they could or nor?
Alchemist have no Caster Level, and cannot take Craft (magic item) Feats, at all.
Based on this FAQ, you cannot even select magic item creation feats, let alone use your Extracts to qualify as the prerequisites.
Because of this, and the fact that Extracts "behave like spells in Potion form" it follows that Extracts do not count as the ability to cast a spell any more than a potion would.
However, you can still make magic items with Master Craftsman or a similar workaround.
Even without the ability to meet magic item creation prerequisites, such as casting a specific spell, you may create items by increasing the craft DC by 5 for each unmet prerequisite, such as an unknown spell. Alternately, you can hire another to expend the spell on your behalf, keeping the original DC but increasing the price mildly.
No, your formulae don't help you make magic items.
(Except potions, of course, as the alchemist has a class feature specifically to let them to that. But you already know that.)
First, the alchemist does not have a caster level, and thus can't normally acquire other item creation feats. The rules for the alchemist class mentions under alchemy:
The alchemist uses his level as the caster level to determine any effect based on caster level.
Similar phrases appear elsewhere in the class description, such as under Brew Potion. Such phrases do not appear in full spell-casting classes such as the wizard or sorcerer, so one could infer that the alchemist does not actually have a caster level. As such, alchemists cannot satisfy the caster level requisites for item creation feats, a fact affirmed in this FAQ.
There are ways around this limitation. You could multiclass into a spell-casting class to gain caster levels. Or you could acquire the Master Craftsman feat, which grants limited access to magic item crafting by letting your ranks in a Craft or Profession skill count as your caster level for acquiring certain item creation feats.
Suppose you were to gain access to an item creation feat as an alchemist. You could create items which do not require spells, such as +1 weapons or +1 armour. For many items, you can choose to ignore prerequisites in exchange for increasing the crafting DC by 5 per prerequisite, and this includes spells. If you were to get your hands on a wand or staff or other spell-trigger item with a spell on your formula list, or a friend who could cast the spell you wanted, you could use them to fulfil the spell prerequisite (alchemists can't use scrolls). Or you could find another way to cast a spell, such as via the Spell Knowledge discovery.
But can you use your formulae to satisfy the spell prerequisite for magic items?
As you have correctly identified from the class description,
the alchemist doesn’t actually cast spells,
instead the alchemist creates extracts. Regarding extracts:
In many ways, they behave like spells in potion form ...
An extract is “cast” by drinking it, as if imbibing a potion—the effects of an extract exactly duplicate the spell upon which its formula is based
So an extract, the alchemists' primary means of delivering spells, is almost identical to a potion. Let us now check what it takes to fulfil the spell requirements from crafting magic items:
A spell prerequisite may be provided by a character who has prepared the spell (or who knows the spell, in the case of a sorcerer or bard), or through the use of a spell completion or spell trigger magic item or a spell-like ability that produces the desired spell effect.
A potion is a use activated item, not a spell completion (e.g. scroll) or spell trigger (e.g. wand, staff) item, so does not qualify for providing a spell prerequisite. Since extracts are like potions, extracts also do not qualify for creating magic items.
However, while the alchemist is still fairly poor in their ability to make magic items, they are assisted by the Material Mastery discovery.
By expending an extract of the same school and level as a spell prerequisite when crafting a magic item, you take only a –2 penalty for ignoring that requirement, instead of –5.
However, note that you don't have to use the same spell as the one you need, just one of the same school and level, so your specific formulae don't help you in making magic items. You just need to have any formula of the same level and school, and even then you don't actually satisfy the spell prerequisite, only reduce the penalty for ignoring the prerequisite.
Update .... Yes they can directly but only if crafting constructs and you took the construct rider archetype. From the paizo book cohorts and companions.
**Yes they can help you craft magical items but Not usually by themselves and usually indirectly by lessening penalties for a requirement.**this will take some building
Your goal is to make magic items as an alchemist. Lets get you there.
From cohorts and companions.....take the spell knowledge discovery.......blah blah. you can prepare and cast this spell as an arcane spell....your caster lvl is equal to your alchemist lvl.....your considered to have this spell for purposes of prerequisites n spell completion /trigger items uses an extract slot one higher than typicall. Congrats you now are a bonified caster (not sla) complete with caster level. It may only be one spell ,but You now qualify for lots of item creation feats. Can take at level two. You will cast a cantrip as a 1st lvl slot and you can start crafting wonderous items at lvl 3.
However to make any cool items you need a full list of spells right right? Nope,take material mastery from cohorts and companions as a discovery. While you cant eliminate the penalty for not having the proper spells(-5) completely. this allows you to use an extract of the same lvl and school to make the penalty only -2. In a game where the gm forgets to include scrolls on a regular basis you might have a leg up on the wizard crafter. Also at this point you dont care whose spells list they are on you take only -2. Just remember spell completion or trigger items say you must have the exact spell in question.take at lvl 4.
Alternatively to spell knowledge. If all you want to craft is golems as your magic item of choice, then take promethean disciple from occult adventures. You still suffer penalties for missing spells but you can make them with craft alchemy instead of spell craft. Yah know,alchemy? the skill you already get 1/2 lvl bonus to? Get an extra half by going heart of the fields if your human.add 4 inteligence mod and skill focus for a +50 by 20th lvl. Just in time to make an adamantine golem at dc 60 with no spells. Remember to grab material mastery to get your extracts to help.
Like the other posts said master craftsman will allow you to make magical items for one craft skill you have 5 ranks in. However its very limiting on the kind of created items involved. If your looking to craft your own weapon or armor from exotic materials, make them magical , and youd really rather spend skill points and 1 feat instead of a discovery and two feats, well we all make choices. Granted master craftsman starts at lvl 5 and as an alchemist you can spell knowledge at 2nd(choose a 0 lvl spell cast as 1st) and craft wondrous at lvl 3 like every body else.
Your using craft checks to make magic items? Drink the extract crafters fortune for a +5 competence bonus. Ie ignore one construction requirement.
Happy crafting and show up that wizardy friend who always made fun of you for smelling funny.