In Table 7 on page 15 of the Prometheum Exxet, there is an entry for "one whole day". I know that if I spend a week crafting each item, it takes an 8-hour period per day to do. How much, though, is "one whole day"?
The rules on forging state
"Keep in mind that a day of work is equal to 12 hours work in an adequately equipped workshop or smithy."
Arguing from that, one day of work would be 12 hours of mostly uninterrupted work, allowing for short breaks like eating and whatnot.