Wikia

Arcane Blast
Arcane Blast 30 yd range None cooldown 7% of base mana 2.5 sec cast Blasts the target with energy, dealing X Arcane damage. Each time you cast Arcane Blast, the damage of all Arcane spells is increased by 15% and mana cost of Arcane Blast is increased by 175%. Effect stacks up to 4 times and lasts 6 sec or until any Arcane damage spell except Arcane Blast is cast.
Usable by
Class	Mage
Properties
Type	Offensive
School	Arcane
Cooldown	None
Talents
Improvement talents	Arcane Subtlety, Arcane Focus, Arcane Impact, Arcane Instability, Spell Power, Playing with Fire, Molten Fury, Shatter, Precision
Other information
Ranks	4
Related debuff
Arcane Blast Arcane spell damage increased by 15% and mana cost of Arcane Blast increased by 175%. Duration: 6 seconds

Arcane Blast is a mage spell that deals direct arcane damage, with increasing damage levels and mana costs when cast in succession. With careful management, the mage can use this spell to trade off damage per mana versus damage per second.

Rank table

Rank	Damage	Level	Cost
1	842 - 978	64	6 30
2	897 - 1041	71	15
3	1017 - 1215	76	15
4	1185 - 1377	80	15

Each cast will apply a debuff "Arcane Blast" to the mage that increases damage done by arcane spells but increases Arcane Blast's mana cost. This debuff will stack up to four times, and lasts 6 seconds. The values are listed below:

# of Buffs	Reported in Buff Tooltip		Reported in Spell Tooltip
# of Buffs	Damage done	Mana Cost Increase	Mana Cost
0	-	-	7% of base mana
1	Base damage + 15%	Base cost + 175%	19% of base mana
2	Base damage + 30%	Base cost + 350%	32% of base mana
3	Base damage + 45%	Base cost + 525%	44% of base mana
4	Base damage + 60%	Base cost + 700%	56% of base mana

When the effect is active, the next arcane damage spell you cast will have its damage increased and consume the effect, making Arcane Blast a useful way to power up your spells.

Cataclysm table

Level	Damage
80	1888

Notes

This spell is available at level 64 (and therefore, only available to players with the Burning Crusade expansion).

The 3-second debuff duration is meant to make the spell interesting in a rotation along with Arcane Barrage. If both are rotated, the Arcane Mage can achieve high DPS while not having to deal with the debuff, as there won't be time to refresh it between Arcane Barrage-Arcane Blast cycles.

It had been reported that mana increasing modifiers such as arcane power or 2/5 mage T5 set bonus add to the % listed in the table above rather than multiply the mana cost listed in the last column, meaning they get more "relatively effective" as you stack the AB debuff higher. The practical result means that if you're going to spam AB with 3 debuffs stacked for some parts of the fight due to excessive mana supply, it's best to do it during arcane power uptime, as the relative increase in mana cost is, at that time, lower than the relative damage increase, compared to what you would get if you used arcane power and arcane blast spamming at different timeframes.

Improvements

Talents

Arcane

[Arcane Subtlety] reduces the threat generated by Arcane spells by 20/40%.
[Arcane Focus] increases the chance to hit by 1/2/3% and reduces the mana cost of Arcane spells by 1/2/3%.
[Arcane Concentration] gives you a 2/4/6/8/10% chance of entering a Clearcasting state after any damage spell hits a target. The Clearcasting state reduces the mana cost of your next damaging spell by 100%.
[Magic Attunement] increases the range of Arcane spells by 3/6 yards.
[Arcane Meditation] allows 17/33/50% of your mana regeneration to continue while casting.
[Torment the Weak] makes your Frostbolt, Fireball, Frostfire Bolt, Pyroblast, Arcane Missiles, Arcane Blast, and Arcane Barrage abilities deal 4/8/12% more damage to snared or slowed targets.
[Focus Magic] increases the target's chance to critically hit with all spells by 3%. When the target critically hits the caster's chance to critically hit with spells is increased by 3% for 10 sec. Cannot be cast on self.
[Presence of Mind] will, when activated, cause your next Mage spell with a casting time less than 10 sec to become an instant cast spell. Also required for Arcane Potency, Arcane Instability and Arcane Power (see below).
[Arcane Mind] increases your total Intellect by 3/6/9/12/15% (which boosts your critical strike chance and Mind Mastery, see below).
[Arcane Potency] increases the critical strike chance of your next damaging spell by 15/30% after gaining Clearcasting or Presence of Mind.
[Arcane Instability] increases your spell damage and critical strike chance by 1/2/3%
[Arcane Power] will, when active, cause your spells to deal 20% more damage while costing 20% more mana to cast. This effect lasts 15 sec.
[Arcane Empowerment] increases the damage of all party and raid members within 100 yds by 1/2/3% (among other effects).
[Mind Mastery] increases spell damage by up to 3/6/9/12/15% of your intellect.
[Netherwind Presence] increases your spell haste by 2/4/6%.
[Spell Power] increases critical strike damage bonus of all spells by 25/50%.

Fire

[Incineration] increases the critical strike chance of your Fire Blast, Scorch, Cone of Cold and Arcane Blast spells by 2/4/6%.
[Impact] gives your damaging spells a 4/7/10% chance to cause the next Fire Blast you cast to stun the target for 2 sec.
[Master of Elements] causes your spell criticals to refund 10/20/30% of their base mana cost.
[Improved Scorch] increases your chance to critically hit with Scorch, Fireball and Frostfire Bolt and your damaging Scorch spells have a 33/66/100% chance to cause your target to be vulnerable to spell damage, increasing spell critical strike chance against that target by 5% and lasts 30 sec.
[Playing with Fire] increases all spell damage caused by 1/2/3% and all spell damage taken by 1/2/3%.
[Pyromaniac] increases chance to critically hit by 1/2/3% and allows 17/33/50% of your mana regeneration to continue while casting.
[Molten Fury] increases damage of all spells against targets with less than 35% health by 6/12%.
[Burnout] increases your spell critical damage bonus with all Fire spells by 10/20/30/40/50% but your spell criticals cost an additional 1/2/3/4/5% of the spell's cost.

Frost

[Precision] reduces the mana cost of your spells by 1/2/3% and increases your hit rating by 1/2/3%.
[Shatter] increases the critical strike chance of all your spells against frozen targets by 17/34/50%.
[Frost Channeling] reduces the mana cost of all spells by 4/7/10% and the threat caused by your Frost spells by 4/7/10%.
[Winter's Chill] increases your chance to critically hit with Frostbolt by an additional 1/2/3% and gives your Frost damage spells a 33/66/100% chance to apply the Winter's Chill effect, which increases the chance spells will critically hit the target by 1% for 15 sec. Stacks up to 5 times.
[Fingers of Frost] gives your Chill effects a 7/15% chance to grant you the Fingers of Frost effect, which treats your next spells cast as if the target were Frozen (used together with Shatter, see above). Lasts 15 sec.

Glyphs

[Glyph of Arcane Blast] increases the damage from your Arcane Blast buff by 3%.

Equipment

Equipment Sets

Tirisfal Regalia - 2/5 will increase the damage and mana cost of Arcane Blast by 20%.
Valorous Kirin Tor Garb - 2/5 will give your Arcane Blast, Frostbolt, Frostfire Bolt, and Fireball spells to have a chance of granting you 350 spell power for 15 sec.
Conqueror's Kirin Tor Garb - same as above.
Conqueror's Khadgar's Regalia - 4/5 increases the critical strike chance of your Fireball, Frostbolt, Frostfire Bolt, and Arcane Blast spells by 5%.
Triumphant Khadgar's Regalia - same as above.
Triumphant Khadgar's Regalia (heroic) - same as above.
Conqueror's Sunstrider's Regalia - same as above.
Triumphant Sunstrider's Regalia - same as above.
Triumphant Sunstrider's Regalia (heroic) - same as above.

Tips and tactics

The mana cost increase will run you out of mana VERY quickly. While debuffless Arcane Blast is fairly efficient in terms of DPM, a single-debuff stack will already triple the mana cost for a very disproportionate DPM imbalance. Spamming this spell is very inefficient and virtually unsustainable even in the presence of such elements as Innervate and Replenishment.

As of patch 3.0.8, Arcane Blast has been reworked. The debuff it applies increases the damage of the next arcane damage spell you cast. Arcane Blast will add another stack, while all others will consume the effect. This makes Arcane Blast a good way for arcane mages to power up their spells and increase their damage.

An arcane mage's main nuke, therefore, should consist of alternating Arcane Blast with Arcane Barrage. This way the blast provides efficient damage while the barrage consumes and receives bonus damage from the power-up.

For shorter fights you might decide to build more than one stack of power before releasing it with another arcane spell. However, for longer fights this probably won't be a very wise use of mana.

Watch and listen for Missile Barrage. Casting Arcane Blast before firing Arcane Missiles will increase the talent's effectiveness.

Also watch for Clearcasting. If this procs when you already have a stack of power, your next blast will get all of the extra damage and none of the extra cost.

Arcane Blast is like Scorch (and unlike Fireball, Frost Bolt, and Arcane Missiles) in that it doesn't have a projectile animation. This makes the mage a bit less obvious in PvP combat as Arcane Blast won't leave a brilliant pointer back to the caster. Also, it's pretty hard to keep the debuff going as you'll hardly have time to sit around spamming 2.5 second casts (luckily for you).

Patch changes

Patch 3.2.2 (2009-09-22): The buff from using this ability now stacks up to 4 times instead of 3, and each application increases mana cost by 175% instead of 200%. In addition, the duration of the buff has been reduced to 6 seconds.
Patch 3.2.0 (04-Aug-2009): Mana cost reduced by 12%.
Patch 3.1.0 (14-Apr-2009): Stacking effect is no longer considered a Magic effect and will not be dispelled.
Formerly it was considered a harmful magical effect and would be dispelled by friendly casters, sometimes by accident, other times because of other magic debuffs.
Patch 3.0.8 (2009-01-20): This ability has been significantly changed. Arcane Blast now increases the damage of the next Arcane spell by 15%. However, using Arcane Blast itself does not consume the charge itself. Each time you cast Arcane Blast, the damage of Arcane spells is increased by 15% and the mana cost of Arcane Blast is increased by 200%. This effect stacks up to 3 times and lasts 10 seconds or until any Arcane damage spell except Arcane Blast is cast.
/ Patch 3.0.2 (14-Oct-2008): The debuff was changed from a cast time reduction to a pure damage increase, and the mana cost penalty was massively increased. Debuff duration changed from 8 to 3 seconds.
Patch 2.1.0 (22-May-2007): The Arcane Blast debuff can no longer be dispelled.
Patch 2.1.0 (22-May-2007): A data error was fixed that was causing Arcane Blast to generate more threat than intended.