Abstract: This invention pertains to heat transfer fluid conduit wrapping for vessels particularly as shown in U.S. Pat. Nos. 3,318,376 issued May 9, 1967 and 3,452,568 issued July 1, 1969. In those patents is shown wrapping which is specially contoured to provide outwardly extending flare edges on each side of a generally rounded, central portion. That wrapping is fabricated in determined lengths, and is made a fluid conducting passageway by welding its edges to a vessel wall and by welding one end to the adjacent end of a succeeding length. Welding of wrapping either at its edges or ends may be by one or more passes. The welding of one segmental wrapping length to the next length may, according to the present invention, include a specially shaped inner reinforcing member, and a transverse cut or an angled cut of twenty to forty-five degrees at the end of the wrapping may be made.