Found in Gordon's locker, at the secret bunker.
This is a list showing which items are required to make a Flax cap-ice-i-tor, which is needed to repair the De-lore-ing device (incomplete), making it into a functional De-lore-ing device.
Will tell you to retrieve the following items:
Something to cap it all off (Hat)
Something to bind the pieces together (Flax)
Something to keep the device cool (Ice cubes)
Something Thor-ific (Hammer)
The knowledge to bring it all together (The Penguin Book of Gielinor)
Gordon's record of where he hid components to finish his de-lore-ing device