1 Tal Rune + 1 Thul Rune + 1 Perfect Topaz + Normal Body Armor = Socketed Body Armor of same type
Using this recipe in cube with any non magic, non rare, non unique armor or Eth armor will give it 1 to 4 sockets. The ETh armor are to be used on Merc only. The best you can expect to roll runewords are 4 sockets (Stone and Fortitude for very high values), eventually 3 soc (duress, enigma, treachery low value), 2 soc (prudence, for self use only)
But mainly the bug consists in re applying the ETh bonus of defence (50%) , meaning , the defence of the Eth armor is again x 1.5 in the cube.
Example: Sacred armor 600 def.
The Eth armor has 600 *1.5 = 900 def
The bugged socketed eth armor has 1350 def.
Of course, this is a maximum. To be worth bugging, your eth armor should have at least 670+ def to get 1000+ def.
1100+ bugged armors have good value in trading.
How to find "white" armor and eth armor: run with no magic find on a character (pits, or cows)
You can only bug ETHEREAL armor.
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