@Pigs this wire will get you in the ballpark you're wanting but will probably need 6 wraps for a 2.5id.
$4.02 (Free or Cheap Shipping) 316L Stainless Steel Tri-Core Heating Wire (316L SS(tri-core), 3*28/38 AWG, 10ft) at m.FastTech.com
$4.02 (Free or Cheap Shipping) 316L Stainless Steel Tri-Core Heating Wire (316L SS(tri-core), 3*28/38 AWG, 10ft) at m.FastTech.com