I tend to use Araldite it does take a wee while to cure 24 hrs but cures faster when warmer as most of the glues for sticking metal to metal are 2 part epoxy then most of those should do simple sticking metal to metal but not in an area where any load is applied
There are 3 companies producing metal bonding products for the autobody industry that Ive used.SEM,Lord fusor and 3m.At our shop we are currently using the SEM line.All are very strong.We actualy performed a rip test with the SEM vs. a welded tab..The weld failed first.
They are all 2 part products that require a special caulking gun for application.While the products themselves are reasonably priced,the caulking guns required are rediculously overpriced.
As someone mentioned, its high heat that will cause these products to fail.In the nieghborhood of 800degrees.So wouldnt recomend using them around the engine.As with any glue application is crytical.If you dont grind both sides of the metal,it will fail.
:newsmile100:
...and it comes in different colors, you could match you paint!
I've used JB Weld in a pinch on non critical parts. Trick is to clean the surfaces with alcohol or something similar before applying and letting it cure 24hrs. A part I've "glued" is holding together 2yrs later...your mileage may vary.