You need to be at least level one in Craftsmanship.
Fortunately, if it's not part of your build there is another way to get it quickly. (see Extreme difficulty below)
Don't waste any level points on craftsmanship in the early parts of the game. Science should be first, get that to level 3 and then work on Vigor with actual points from leveling up.
There's a piece of armour that seems to drop every now and then from enemies on the streets on New Sèrenè and San Matheus.
"Thick Blacksmith's Gloves" are what you are looking for. They unlock an extra level in craftsmanship when you are wearing them. Giving you access to fairly low level upgrades on Weapons and armour. Wear them at a crafting table and craft the upgrades.
Companion armour counts too, mine unlocked after kitting out Petrus.