> After cleaning, reaming, scaping, filing, expropriating, What Do You Do
> Next?  What kind of crud do you put in there?
> 

Add sandblasting, and etching.  Then apply a quality metal etching 
primer, PPG products my favorite, or a good epoxy primer, let cure, 
then fill with a quality automotive seam sealer, comes in caulk tube, 
there are many brands etc, 3M makes good stuff, others equal, just 
buy it at a good busy auto paint store who knows their stuff.  Will 
set you back a fair piece of change ($15/tube or so).  Then maybe 
reapply the epoxy primer, top coat etc.  If the rust is very severe, 
you will have to smooth the bumps out a bit with bondo before doing 
the origional seam.  Avoid the temptation to bondo the entire seam, 
it will not work or hold up.  Bondo the edges of the body carefully 
(after the first coat of primer if using PPG stuff), sand it nice and 
flat, prime again, then seam sealer, etc.

John
vwbus@netbiz.net