A method for forming a porous soot body that includes depositing soot on a release coating supported by a bait substrate. Characteristics of the release coating control the strength of attachment of the porous soot body to the bait substrate. Weak attachment of the porous soot body to the bait substrate facilitates separation of the porous soot body from the bait substrate without damaging the porous soot body. The release coating may be formed from a brittle material or a material that oxidizes or otherwise depletes during deposition of the soot that forms the porous soot body. The release coating may include carbon. The separated porous soot body may be consolidated to form a core cane or may function as a sleeve (porous cladding) in a cane-in-soot fiber preform manufacturing process.