A quick search with Google came up with:

1) Lord Fusor (DuPont I believe)
2) Duramix (3M)
3) SEM
4) Liquid Nails LN-203

I need to do rockers/door jams, cab corners and lower bed edges all due to rust. I just wanted to cut rust out. Put panels in. Putty up. Sand and put a chromed panel over. I got to do something with bed fenders they are bad.

 

3M is probably the most available. Any local auto paint supplier should have it. The caulking gun is expensive. I have been using the adhesive from Eastwood that comes in smaller, cheaper tubes and each tube comes with an adapter to use in a regular caulking gun.

 

Fusor has been around a long time and has been crash-tested. Norton also makes Speedgrip. The body shops I know of use those, but SEM should be fine too.