I've used it with some success, doesn't work as good for seams.  You
really need to get it clean first.  Did the nose of my '70 bus with it.
kept the rust away until I sold it.  Haven't seen it since, that was 5
years ago.  I've got some now and plan to use it on the steel pipes in
the engine compartment of my camper.  They're not real rusty yet, but
getting those 1.9L pipes are getting tough.  Apparently VW does think
they rust out, or that that cooling system changed in 86 so their aren't
many left.  Because you can't get them from VW.  Especially the pipe
that runs over the top of the engine. Boy are they wrong, lots of 1.9L's
left.  So I'm hoping the POR-15 will keep it lasting a bit longer.
--
                             -Jim DiGennaro
     '84 Green Westfalia 'The Turtle Van',  '90 Jetta (Brides car)
                  '92 Scamp Trailer 'The Turtle's Egg'
                              ICQ# 5534528
                       LiMBO LINE: (413) 743-1814
                     URL: http://www.bcn.net/~limbo