Shawn,
If you have any, standard 1.25" copper plumbing pipe is exactly the right
internal diameter to slip tightly over the cut ends of the VW coolant
pipes.  I had to cut down the steel coolant pipes in my 84 Westy for an
engine conversion, and like you, was concerned about leaving them without
some kind of flare or bead at the ends.  I cut a couple narrow rings of the
copper and slipped them on the steel lines with lots of JB Weld... forms a
good strong bead.  No leaks in 20K+ miles anyway.
best,
Robert H
84 Westy "Busaru" - about to go into winter hibernation
<www.people.cornell.edu/pages/rdh24/vw/index_vw.html>

>The steel coolant lines on my '82 diesel Westy had the typical rust in the
>last 18" of pipe, so I cut this out and replaced with marine coolant/exhaust
>hose, sized to fit over the steel pipe. For now, I have double clamped
>each joint, as they are prone to slipping, since there is no 'flare' on the
>pipe where it was cut. Now I have a friend facing the same issue no their
>'85.
>Ideas that have come up so far as: 1) welding a bead around the pipe to
>simulate the stock flare. 2) Buying the expensive tool to create the flare in
>the pipe (way too expensive!).
>
>Any other ideas? The drawback with welding is having to remove the
>whole length of pipe (and presumably the fuel tank as well). Unless I can
>bend a wire around the end of the pipe and just tack it in place in a few
>spots with the pipe installed...
>
>In both vans, the pipes appear pristine except for the rearmost 18", so
>replacing the whole lot seems overkill. But maybe 1.5" hose the whole
>way is a better choice long term? The marine hose I used is much larger
>(very thick), so I don't know if it will fit in some of the tight spots.
>
>Ideas welcome...
>
>Shawn Wright
>http://zuiko.sls.bc.ca/~swright
>'85 Jetta D
>'88 Westy 1.6TD 5 speed
>  (see progress at http://members.shaw.ca/vwdiesels)
>'82 Diesel Westy