Ignis the Furnace Master

Ignis the Furnace Master is one of the encounters in Ulduar without two difficulty modes.

Encounter Details

Ignis the Furnace Master

Basics
HP: 19.5 million (Heroic) / ?? million (Normal)
Damage: 25k melee (Heroic)
Enrage: Unknown
Abilities
Flame Jets
Stomps the ground causing geysers of flame to errupt under all enemies. These geysers deal 8483 to 9517 Fire damage, knocking the targets into the air and interrupting any spells being cast for 8 sec. In addition, the targets take 2000 Fire damage per second for 8 sec.
Scorch
Fires a jet of flame, burning all enemies in front of the caster within 30 yards, dealing 3770 to 4230 Fire damage every half-second for 3 sec. Additionally, the ground is scorched by this effect causing it to catch on fire, dealing 7540 to 8460 Fire damage every second to all enemies within 13 yards. Iron Constructs within this radius will begin to heat up, eventually becoming molten.
Slag Pot
Charges and grabs a random enemy target, tossing them into the caster's slag pot. The target is unable to attack the caster and takes 7500 Fire damage every second for 10 sec. If the target survives, they are imbued with the magical slag, increasing their haste by 150% for 10 sec.
Strength of the Creator
Every time a construct spawns, Ignis' damage is increased by 20%.  This stacks up to 99 times.  Destroying a construct removes a stack.
Comments: Every minute or so Ignis will activate an Iron Construct.

Iron Construct

Basics
HP: 3.8 million (Heroic and Normal)
Mana: None
Enrage: Unknown
Tactics
The basic idea for dealing with the Iron Constructs is that you drag them through the ground effect left by Scorch.  This will cast Heat on the construct.
 
Once Heat stacks to 20, it turns into a Molten Construct and the next step begins.  Now drag the Molten Construct into the water nearby and freeze it, turning them Brittle.
 
After they've turned Brittle, you must deal 5000 or more damage to them in a single attack; this will shatter them, destroying the Construct and removing a stack of Strength of the Creator from Ignis.
Heat
Blasts all nearby Iron Constructs with intense heat, increasing their movement speed by 5 and haste by 5. This effect stacks up to 20 times. If this effect stacks to 20, the affected Iron Construct will become Molten.
Molten
Molten also increases haste by 100%.  Once a construct becomes Molten, drag them through the water.  Once in the water, the construct freezes up and they become Brittle, allowing you to shatter it.
Brittle
Stunned. Chance to receive critical hits increased by 50%. Shatters if dealt 5000 damage or more in a single attack. (Shatter)

Video

Now that you've read up on the encounter, take a moment and watch this video to see things in action.

Wretched of Cenarius-US