The item you're repairing matters, but the most important thing is.... Break Count.
Newly crafted stuff is easy to repair. Encounter guns are hard to repair. They have multiple break counts.
Every time you repair, you add a break count, unless the item is broken completely and you repair it fully.
Use the Search, there should be a few topics on this.
So, an Armorer 3, with 180% repair, should be able to repair most things with a tool, and almost everything with a super tool kit. 200% repair plus a tool or super tool kit should be plenty for any repairs you need.