Besides ordering of the internet, where can I publicy/physically buy seam sealer? Have been to some not all Auto Parts stores to no avail. ?

Autopaint shops. 3M makes some that most NAPA stores can order if you give them the number. 08656 is 3M brushable seam sealer. You can also get sprayable, but you need the gun to spray it.

I like the caulking gun two part type. SEM makes some very exp but it also has pasivating agent
TCP web site has god product descriptions and good prices
http://www.tcpglobal.com/autobodydepot/

Look in phone book for Auto Body Supply (may be under the Business-to-Business yellow pages one. I think there's a big one in Santa Ana just south of downtown area, or used to be there any-hoo.

Also decide whether you will use it on top of good epoxy primer or on the bare metal before the primer, read up on it first, as Sean has linked to.

This is a place I use if I don't get what I need from my regular auto paint store. I will never give up trying to find a way to get a fleet discount on prices though.

http://www.autobodytoolmart.com/search/sea...rds=seam+sealer

Early cars had brush on and later cars had spray on. We used Wurth and a Schutz gun to emulate the original finish.

Like this one Eric?

gun