You may sacrifice three artifacts rather than pay this spell's mana cost.
Exile three artifact cards from your graveyard: Return Salvage Titan from your graveyard to your hand.
The only difference between a colored artifact and a colorless artifact is, obviously, its color. Unlike most artifacts, a colored artifact requires colored mana to cast. Also unlike most artifacts, a colored artifact has a color in all zones. It will interact with cards that care about color. Other than that, a colored artifact behaves just like any other artifact. It will interact as normal with any card that cares about artifacts, such as Shatter or Arcbound Ravager.
Casting Salvage Titan by paying its alternative cost doesn’t change when you can cast it. You can cast it only at the normal time you could cast a creature spell.
You may activate the second ability only if Salvage Titan is in your graveyard. To pay this ability’s cost, you may exile any three artifact cards in your graveyard — including Salvage Titan itself. If you exile it to pay the cost, however, it won’t be returned to your hand when the ability resolves.