Don't silicone! Resoldering is definitely in order, but with an extra ounce of prevention. Metal has a tendency to expand and contract with changes in weather conditions. Thoroughly clean the area down to bare metal. Drill 1/8-inch diameter holes every six inches along the seam where the pieces overlap each other. Purchase a pop-rivet kit from your local hardware store (about $15) and install a pop-rivet in each hole. Finally, resolder along the old seam and at each pop-rivet.

Remember: Rust, paint, oil and other debris will prevent a proper connection. The key here is to use a torch-heated soldering iron. Heat from direct flame could be dangerous.