pipe clamps
wrap it at the top a bit, then clamp it tight, then continue to wrap it down the pipe - often a strategic twist means you can come back up another pipe and only have to cut once
i think it also helps to have the wrap a bit damp
on another note i'll be doing this to a set of extractors i managed to get for my excel!!! w00t
$120 for old, but unused, anodized mild steel 4-1 extractors....