8 mana + Crumble VS Harshforge Plate + rune

[Santar]

Hi Mages!

We have 8 mana and use full action to Crumble Dwarfs Harshforge Plate with +1 armor rune. Will we sucsess?

I think yes! Because we pay 8 mana to cast, then we recolve effects:
1) Gain 2 mana.
2) Destroy armor, and while we destroing it we must pay 2 mana for rune. And we have it from step 1.

Am I right?

[Obsidian Soul]

I think so.

[DaveW]

Your gaining of two mana will increase your available mana to 10. Since the Crumble does not have to pay the additional cost from the Harshforge Plate itself (spell does not target the Mage), you then have enough mana to destroy the armor with the rune on it.

[Zuberi]

You are completely correct. During the Pay Cost step, you only pay 8 mana. Then during the Resolve Spell step, you resolve the effects in the order they appear on the card. So you first gain 2 mana, and then you destroy the equipment. When you go to destroy the equipment (after having gained the two mana) you must pay 2 mana due to the Rune in order to succeed at the destruction.

So, yeah, you've got it 100% right.