The rarity of the Workbench defines the maximum rarity of the Frost Tools you can craft there.
For example, if you have an Epic Workbench you can craft Common, Uncommon, Rare and Epic Frost Tools (assuming you have the corresponding FROSTprints and other crafting ingredients) but nothing rarer.
If you wish to upgrade a FROSTprint to the next rarity, the Workbench must be at least as high as that rarity.
(If you are a Big Time player, Frost Workbench are similar to Time Wardens)
Upgrading Frost Workbenches
You can upgrade a Frost Workbenches to the next rarity up to Transcendent. It requires:
2 Frost Workbenches of the same rarity.
Upgrade Points - this increases with rarity
Cryo / FROST
The 2 Frost Workbenches used to make the new one go back into the global pool for recirculation.
Rarity
Frost Workbenches
CRYO (10k)
Upgrade Points
Time (hours)
Uncommon
x2 Common
5
40
3
Rare
x2 Uncommon
12
90
6
Epic
x2 Rare
30
80
12
Legendary
x2 Epic
84
150
24
Mythic
x2 Legendary
168
225
48
Exalted
x2 Mythic
336
300
96
Exotic
x2 Exalted
672
600
192
Transcendent
x2 Exotic
1344
800
384
Note - Numbers may change
How do I obtain a Workbench?
In Mystery Boxes
Buy or Rent from the Open Loot Marketplace
In-game rewards and rare loot drops
Max Issuance
Image
Rarity
Max Supply
Common
64,000
Uncommon
32,000
Rare
16,000
Epic
8,000
Legendary
4,000
Mythic
2000
Exalted
1000
Exotic
500
Transcendent
250
Mythic, Exalted, Exotic and Transcendent have to be made through upgrading.